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17926a79 DH |
1 | /* RxRPC point-to-point transport session 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> | |
5a0e3ad6 | 15 | #include <linux/slab.h> |
17926a79 DH |
16 | #include <net/sock.h> |
17 | #include <net/af_rxrpc.h> | |
18 | #include "ar-internal.h" | |
19 | ||
20 | static void rxrpc_transport_reaper(struct work_struct *work); | |
21 | ||
22 | static LIST_HEAD(rxrpc_transports); | |
23 | static DEFINE_RWLOCK(rxrpc_transport_lock); | |
24 | static unsigned long rxrpc_transport_timeout = 3600 * 24; | |
25 | static DECLARE_DELAYED_WORK(rxrpc_transport_reap, rxrpc_transport_reaper); | |
26 | ||
27 | /* | |
28 | * allocate a new transport session manager | |
29 | */ | |
30 | static struct rxrpc_transport *rxrpc_alloc_transport(struct rxrpc_local *local, | |
31 | struct rxrpc_peer *peer, | |
32 | gfp_t gfp) | |
33 | { | |
34 | struct rxrpc_transport *trans; | |
35 | ||
36 | _enter(""); | |
37 | ||
38 | trans = kzalloc(sizeof(struct rxrpc_transport), gfp); | |
39 | if (trans) { | |
40 | trans->local = local; | |
41 | trans->peer = peer; | |
42 | INIT_LIST_HEAD(&trans->link); | |
43 | trans->bundles = RB_ROOT; | |
44 | trans->client_conns = RB_ROOT; | |
45 | trans->server_conns = RB_ROOT; | |
46 | skb_queue_head_init(&trans->error_queue); | |
47 | spin_lock_init(&trans->client_lock); | |
48 | rwlock_init(&trans->conn_lock); | |
49 | atomic_set(&trans->usage, 1); | |
50 | trans->debug_id = atomic_inc_return(&rxrpc_debug_id); | |
51 | ||
52 | if (peer->srx.transport.family == AF_INET) { | |
53 | switch (peer->srx.transport_type) { | |
54 | case SOCK_DGRAM: | |
55 | INIT_WORK(&trans->error_handler, | |
56 | rxrpc_UDP_error_handler); | |
57 | break; | |
58 | default: | |
59 | BUG(); | |
60 | break; | |
61 | } | |
62 | } else { | |
63 | BUG(); | |
64 | } | |
65 | } | |
66 | ||
67 | _leave(" = %p", trans); | |
68 | return trans; | |
69 | } | |
70 | ||
71 | /* | |
72 | * obtain a transport session for the nominated endpoints | |
73 | */ | |
74 | struct rxrpc_transport *rxrpc_get_transport(struct rxrpc_local *local, | |
75 | struct rxrpc_peer *peer, | |
76 | gfp_t gfp) | |
77 | { | |
78 | struct rxrpc_transport *trans, *candidate; | |
79 | const char *new = "old"; | |
80 | int usage; | |
81 | ||
21454aaa HH |
82 | _enter("{%pI4+%hu},{%pI4+%hu},", |
83 | &local->srx.transport.sin.sin_addr, | |
17926a79 | 84 | ntohs(local->srx.transport.sin.sin_port), |
21454aaa | 85 | &peer->srx.transport.sin.sin_addr, |
17926a79 DH |
86 | ntohs(peer->srx.transport.sin.sin_port)); |
87 | ||
88 | /* search the transport list first */ | |
89 | read_lock_bh(&rxrpc_transport_lock); | |
90 | list_for_each_entry(trans, &rxrpc_transports, link) { | |
91 | if (trans->local == local && trans->peer == peer) | |
92 | goto found_extant_transport; | |
93 | } | |
94 | read_unlock_bh(&rxrpc_transport_lock); | |
95 | ||
96 | /* not yet present - create a candidate for a new record and then | |
97 | * redo the search */ | |
98 | candidate = rxrpc_alloc_transport(local, peer, gfp); | |
99 | if (!candidate) { | |
100 | _leave(" = -ENOMEM"); | |
101 | return ERR_PTR(-ENOMEM); | |
102 | } | |
103 | ||
104 | write_lock_bh(&rxrpc_transport_lock); | |
105 | ||
106 | list_for_each_entry(trans, &rxrpc_transports, link) { | |
107 | if (trans->local == local && trans->peer == peer) | |
108 | goto found_extant_second; | |
109 | } | |
110 | ||
111 | /* we can now add the new candidate to the list */ | |
112 | trans = candidate; | |
113 | candidate = NULL; | |
114 | ||
115 | rxrpc_get_local(trans->local); | |
116 | atomic_inc(&trans->peer->usage); | |
117 | list_add_tail(&trans->link, &rxrpc_transports); | |
118 | write_unlock_bh(&rxrpc_transport_lock); | |
119 | new = "new"; | |
120 | ||
121 | success: | |
122 | _net("TRANSPORT %s %d local %d -> peer %d", | |
123 | new, | |
124 | trans->debug_id, | |
125 | trans->local->debug_id, | |
126 | trans->peer->debug_id); | |
127 | ||
128 | _leave(" = %p {u=%d}", trans, atomic_read(&trans->usage)); | |
129 | return trans; | |
130 | ||
131 | /* we found the transport in the list immediately */ | |
132 | found_extant_transport: | |
133 | usage = atomic_inc_return(&trans->usage); | |
134 | read_unlock_bh(&rxrpc_transport_lock); | |
135 | goto success; | |
136 | ||
137 | /* we found the transport on the second time through the list */ | |
138 | found_extant_second: | |
139 | usage = atomic_inc_return(&trans->usage); | |
140 | write_unlock_bh(&rxrpc_transport_lock); | |
141 | kfree(candidate); | |
142 | goto success; | |
143 | } | |
144 | ||
145 | /* | |
146 | * find the transport connecting two endpoints | |
147 | */ | |
148 | struct rxrpc_transport *rxrpc_find_transport(struct rxrpc_local *local, | |
149 | struct rxrpc_peer *peer) | |
150 | { | |
151 | struct rxrpc_transport *trans; | |
152 | ||
21454aaa HH |
153 | _enter("{%pI4+%hu},{%pI4+%hu},", |
154 | &local->srx.transport.sin.sin_addr, | |
17926a79 | 155 | ntohs(local->srx.transport.sin.sin_port), |
21454aaa | 156 | &peer->srx.transport.sin.sin_addr, |
17926a79 DH |
157 | ntohs(peer->srx.transport.sin.sin_port)); |
158 | ||
159 | /* search the transport list */ | |
160 | read_lock_bh(&rxrpc_transport_lock); | |
161 | ||
162 | list_for_each_entry(trans, &rxrpc_transports, link) { | |
163 | if (trans->local == local && trans->peer == peer) | |
164 | goto found_extant_transport; | |
165 | } | |
166 | ||
167 | read_unlock_bh(&rxrpc_transport_lock); | |
168 | _leave(" = NULL"); | |
169 | return NULL; | |
170 | ||
171 | found_extant_transport: | |
172 | atomic_inc(&trans->usage); | |
173 | read_unlock_bh(&rxrpc_transport_lock); | |
174 | _leave(" = %p", trans); | |
175 | return trans; | |
176 | } | |
177 | ||
178 | /* | |
179 | * release a transport session | |
180 | */ | |
181 | void rxrpc_put_transport(struct rxrpc_transport *trans) | |
182 | { | |
183 | _enter("%p{u=%d}", trans, atomic_read(&trans->usage)); | |
184 | ||
185 | ASSERTCMP(atomic_read(&trans->usage), >, 0); | |
186 | ||
2c6b47de | 187 | trans->put_time = get_seconds(); |
50aab54f | 188 | if (unlikely(atomic_dec_and_test(&trans->usage))) { |
17926a79 DH |
189 | _debug("zombie"); |
190 | /* let the reaper determine the timeout to avoid a race with | |
191 | * overextending the timeout if the reaper is running at the | |
192 | * same time */ | |
651350d1 | 193 | rxrpc_queue_delayed_work(&rxrpc_transport_reap, 0); |
50aab54f | 194 | } |
17926a79 DH |
195 | _leave(""); |
196 | } | |
197 | ||
198 | /* | |
199 | * clean up a transport session | |
200 | */ | |
201 | static void rxrpc_cleanup_transport(struct rxrpc_transport *trans) | |
202 | { | |
203 | _net("DESTROY TRANS %d", trans->debug_id); | |
204 | ||
205 | rxrpc_purge_queue(&trans->error_queue); | |
206 | ||
207 | rxrpc_put_local(trans->local); | |
208 | rxrpc_put_peer(trans->peer); | |
209 | kfree(trans); | |
210 | } | |
211 | ||
212 | /* | |
213 | * reap dead transports that have passed their expiry date | |
214 | */ | |
215 | static void rxrpc_transport_reaper(struct work_struct *work) | |
216 | { | |
217 | struct rxrpc_transport *trans, *_p; | |
218 | unsigned long now, earliest, reap_time; | |
219 | ||
220 | LIST_HEAD(graveyard); | |
221 | ||
222 | _enter(""); | |
223 | ||
2c6b47de | 224 | now = get_seconds(); |
17926a79 DH |
225 | earliest = ULONG_MAX; |
226 | ||
227 | /* extract all the transports that have been dead too long */ | |
228 | write_lock_bh(&rxrpc_transport_lock); | |
229 | list_for_each_entry_safe(trans, _p, &rxrpc_transports, link) { | |
230 | _debug("reap TRANS %d { u=%d t=%ld }", | |
231 | trans->debug_id, atomic_read(&trans->usage), | |
232 | (long) now - (long) trans->put_time); | |
233 | ||
234 | if (likely(atomic_read(&trans->usage) > 0)) | |
235 | continue; | |
236 | ||
237 | reap_time = trans->put_time + rxrpc_transport_timeout; | |
238 | if (reap_time <= now) | |
239 | list_move_tail(&trans->link, &graveyard); | |
240 | else if (reap_time < earliest) | |
241 | earliest = reap_time; | |
242 | } | |
243 | write_unlock_bh(&rxrpc_transport_lock); | |
244 | ||
245 | if (earliest != ULONG_MAX) { | |
246 | _debug("reschedule reaper %ld", (long) earliest - now); | |
247 | ASSERTCMP(earliest, >, now); | |
651350d1 DH |
248 | rxrpc_queue_delayed_work(&rxrpc_transport_reap, |
249 | (earliest - now) * HZ); | |
17926a79 DH |
250 | } |
251 | ||
252 | /* then destroy all those pulled out */ | |
253 | while (!list_empty(&graveyard)) { | |
254 | trans = list_entry(graveyard.next, struct rxrpc_transport, | |
255 | link); | |
256 | list_del_init(&trans->link); | |
257 | ||
258 | ASSERTCMP(atomic_read(&trans->usage), ==, 0); | |
259 | rxrpc_cleanup_transport(trans); | |
260 | } | |
261 | ||
262 | _leave(""); | |
263 | } | |
264 | ||
265 | /* | |
266 | * preemptively destroy all the transport session records rather than waiting | |
267 | * for them to time out | |
268 | */ | |
269 | void __exit rxrpc_destroy_all_transports(void) | |
270 | { | |
271 | _enter(""); | |
272 | ||
273 | rxrpc_transport_timeout = 0; | |
274 | cancel_delayed_work(&rxrpc_transport_reap); | |
651350d1 | 275 | rxrpc_queue_delayed_work(&rxrpc_transport_reap, 0); |
17926a79 DH |
276 | |
277 | _leave(""); | |
278 | } |