Commit | Line | Data |
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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 | ||
5873c083 DH |
20 | /* |
21 | * Time after last use at which transport record is cleaned up. | |
22 | */ | |
23 | unsigned rxrpc_transport_expiry = 3600 * 24; | |
24 | ||
17926a79 DH |
25 | static void rxrpc_transport_reaper(struct work_struct *work); |
26 | ||
27 | static LIST_HEAD(rxrpc_transports); | |
28 | static DEFINE_RWLOCK(rxrpc_transport_lock); | |
17926a79 DH |
29 | static DECLARE_DELAYED_WORK(rxrpc_transport_reap, rxrpc_transport_reaper); |
30 | ||
31 | /* | |
32 | * allocate a new transport session manager | |
33 | */ | |
34 | static struct rxrpc_transport *rxrpc_alloc_transport(struct rxrpc_local *local, | |
35 | struct rxrpc_peer *peer, | |
36 | gfp_t gfp) | |
37 | { | |
38 | struct rxrpc_transport *trans; | |
39 | ||
40 | _enter(""); | |
41 | ||
42 | trans = kzalloc(sizeof(struct rxrpc_transport), gfp); | |
43 | if (trans) { | |
44 | trans->local = local; | |
45 | trans->peer = peer; | |
46 | INIT_LIST_HEAD(&trans->link); | |
47 | trans->bundles = RB_ROOT; | |
48 | trans->client_conns = RB_ROOT; | |
49 | trans->server_conns = RB_ROOT; | |
50 | skb_queue_head_init(&trans->error_queue); | |
51 | spin_lock_init(&trans->client_lock); | |
52 | rwlock_init(&trans->conn_lock); | |
53 | atomic_set(&trans->usage, 1); | |
54 | trans->debug_id = atomic_inc_return(&rxrpc_debug_id); | |
55 | ||
56 | if (peer->srx.transport.family == AF_INET) { | |
57 | switch (peer->srx.transport_type) { | |
58 | case SOCK_DGRAM: | |
59 | INIT_WORK(&trans->error_handler, | |
60 | rxrpc_UDP_error_handler); | |
61 | break; | |
62 | default: | |
63 | BUG(); | |
64 | break; | |
65 | } | |
66 | } else { | |
67 | BUG(); | |
68 | } | |
69 | } | |
70 | ||
71 | _leave(" = %p", trans); | |
72 | return trans; | |
73 | } | |
74 | ||
75 | /* | |
76 | * obtain a transport session for the nominated endpoints | |
77 | */ | |
78 | struct rxrpc_transport *rxrpc_get_transport(struct rxrpc_local *local, | |
79 | struct rxrpc_peer *peer, | |
80 | gfp_t gfp) | |
81 | { | |
82 | struct rxrpc_transport *trans, *candidate; | |
83 | const char *new = "old"; | |
84 | int usage; | |
85 | ||
21454aaa HH |
86 | _enter("{%pI4+%hu},{%pI4+%hu},", |
87 | &local->srx.transport.sin.sin_addr, | |
17926a79 | 88 | ntohs(local->srx.transport.sin.sin_port), |
21454aaa | 89 | &peer->srx.transport.sin.sin_addr, |
17926a79 DH |
90 | ntohs(peer->srx.transport.sin.sin_port)); |
91 | ||
92 | /* search the transport list first */ | |
93 | read_lock_bh(&rxrpc_transport_lock); | |
94 | list_for_each_entry(trans, &rxrpc_transports, link) { | |
95 | if (trans->local == local && trans->peer == peer) | |
96 | goto found_extant_transport; | |
97 | } | |
98 | read_unlock_bh(&rxrpc_transport_lock); | |
99 | ||
100 | /* not yet present - create a candidate for a new record and then | |
101 | * redo the search */ | |
102 | candidate = rxrpc_alloc_transport(local, peer, gfp); | |
103 | if (!candidate) { | |
104 | _leave(" = -ENOMEM"); | |
105 | return ERR_PTR(-ENOMEM); | |
106 | } | |
107 | ||
108 | write_lock_bh(&rxrpc_transport_lock); | |
109 | ||
110 | list_for_each_entry(trans, &rxrpc_transports, link) { | |
111 | if (trans->local == local && trans->peer == peer) | |
112 | goto found_extant_second; | |
113 | } | |
114 | ||
115 | /* we can now add the new candidate to the list */ | |
116 | trans = candidate; | |
117 | candidate = NULL; | |
ed84cadb | 118 | usage = atomic_read(&trans->usage); |
17926a79 DH |
119 | |
120 | rxrpc_get_local(trans->local); | |
121 | atomic_inc(&trans->peer->usage); | |
122 | list_add_tail(&trans->link, &rxrpc_transports); | |
123 | write_unlock_bh(&rxrpc_transport_lock); | |
124 | new = "new"; | |
125 | ||
126 | success: | |
127 | _net("TRANSPORT %s %d local %d -> peer %d", | |
128 | new, | |
129 | trans->debug_id, | |
130 | trans->local->debug_id, | |
131 | trans->peer->debug_id); | |
132 | ||
ed84cadb | 133 | _leave(" = %p {u=%d}", trans, usage); |
17926a79 DH |
134 | return trans; |
135 | ||
136 | /* we found the transport in the list immediately */ | |
137 | found_extant_transport: | |
138 | usage = atomic_inc_return(&trans->usage); | |
139 | read_unlock_bh(&rxrpc_transport_lock); | |
140 | goto success; | |
141 | ||
142 | /* we found the transport on the second time through the list */ | |
143 | found_extant_second: | |
144 | usage = atomic_inc_return(&trans->usage); | |
145 | write_unlock_bh(&rxrpc_transport_lock); | |
146 | kfree(candidate); | |
147 | goto success; | |
148 | } | |
149 | ||
150 | /* | |
151 | * find the transport connecting two endpoints | |
152 | */ | |
153 | struct rxrpc_transport *rxrpc_find_transport(struct rxrpc_local *local, | |
154 | struct rxrpc_peer *peer) | |
155 | { | |
156 | struct rxrpc_transport *trans; | |
157 | ||
21454aaa HH |
158 | _enter("{%pI4+%hu},{%pI4+%hu},", |
159 | &local->srx.transport.sin.sin_addr, | |
17926a79 | 160 | ntohs(local->srx.transport.sin.sin_port), |
21454aaa | 161 | &peer->srx.transport.sin.sin_addr, |
17926a79 DH |
162 | ntohs(peer->srx.transport.sin.sin_port)); |
163 | ||
164 | /* search the transport list */ | |
165 | read_lock_bh(&rxrpc_transport_lock); | |
166 | ||
167 | list_for_each_entry(trans, &rxrpc_transports, link) { | |
168 | if (trans->local == local && trans->peer == peer) | |
169 | goto found_extant_transport; | |
170 | } | |
171 | ||
172 | read_unlock_bh(&rxrpc_transport_lock); | |
173 | _leave(" = NULL"); | |
174 | return NULL; | |
175 | ||
176 | found_extant_transport: | |
177 | atomic_inc(&trans->usage); | |
178 | read_unlock_bh(&rxrpc_transport_lock); | |
179 | _leave(" = %p", trans); | |
180 | return trans; | |
181 | } | |
182 | ||
183 | /* | |
184 | * release a transport session | |
185 | */ | |
186 | void rxrpc_put_transport(struct rxrpc_transport *trans) | |
187 | { | |
188 | _enter("%p{u=%d}", trans, atomic_read(&trans->usage)); | |
189 | ||
190 | ASSERTCMP(atomic_read(&trans->usage), >, 0); | |
191 | ||
22a3f9a2 | 192 | trans->put_time = ktime_get_seconds(); |
50aab54f | 193 | if (unlikely(atomic_dec_and_test(&trans->usage))) { |
17926a79 DH |
194 | _debug("zombie"); |
195 | /* let the reaper determine the timeout to avoid a race with | |
196 | * overextending the timeout if the reaper is running at the | |
197 | * same time */ | |
651350d1 | 198 | rxrpc_queue_delayed_work(&rxrpc_transport_reap, 0); |
50aab54f | 199 | } |
17926a79 DH |
200 | _leave(""); |
201 | } | |
202 | ||
203 | /* | |
204 | * clean up a transport session | |
205 | */ | |
206 | static void rxrpc_cleanup_transport(struct rxrpc_transport *trans) | |
207 | { | |
208 | _net("DESTROY TRANS %d", trans->debug_id); | |
209 | ||
210 | rxrpc_purge_queue(&trans->error_queue); | |
211 | ||
212 | rxrpc_put_local(trans->local); | |
213 | rxrpc_put_peer(trans->peer); | |
214 | kfree(trans); | |
215 | } | |
216 | ||
217 | /* | |
218 | * reap dead transports that have passed their expiry date | |
219 | */ | |
220 | static void rxrpc_transport_reaper(struct work_struct *work) | |
221 | { | |
222 | struct rxrpc_transport *trans, *_p; | |
223 | unsigned long now, earliest, reap_time; | |
224 | ||
225 | LIST_HEAD(graveyard); | |
226 | ||
227 | _enter(""); | |
228 | ||
22a3f9a2 | 229 | now = ktime_get_seconds(); |
17926a79 DH |
230 | earliest = ULONG_MAX; |
231 | ||
232 | /* extract all the transports that have been dead too long */ | |
233 | write_lock_bh(&rxrpc_transport_lock); | |
234 | list_for_each_entry_safe(trans, _p, &rxrpc_transports, link) { | |
235 | _debug("reap TRANS %d { u=%d t=%ld }", | |
236 | trans->debug_id, atomic_read(&trans->usage), | |
237 | (long) now - (long) trans->put_time); | |
238 | ||
239 | if (likely(atomic_read(&trans->usage) > 0)) | |
240 | continue; | |
241 | ||
5873c083 | 242 | reap_time = trans->put_time + rxrpc_transport_expiry; |
17926a79 DH |
243 | if (reap_time <= now) |
244 | list_move_tail(&trans->link, &graveyard); | |
245 | else if (reap_time < earliest) | |
246 | earliest = reap_time; | |
247 | } | |
248 | write_unlock_bh(&rxrpc_transport_lock); | |
249 | ||
250 | if (earliest != ULONG_MAX) { | |
251 | _debug("reschedule reaper %ld", (long) earliest - now); | |
252 | ASSERTCMP(earliest, >, now); | |
651350d1 DH |
253 | rxrpc_queue_delayed_work(&rxrpc_transport_reap, |
254 | (earliest - now) * HZ); | |
17926a79 DH |
255 | } |
256 | ||
257 | /* then destroy all those pulled out */ | |
258 | while (!list_empty(&graveyard)) { | |
259 | trans = list_entry(graveyard.next, struct rxrpc_transport, | |
260 | link); | |
261 | list_del_init(&trans->link); | |
262 | ||
263 | ASSERTCMP(atomic_read(&trans->usage), ==, 0); | |
264 | rxrpc_cleanup_transport(trans); | |
265 | } | |
266 | ||
267 | _leave(""); | |
268 | } | |
269 | ||
270 | /* | |
271 | * preemptively destroy all the transport session records rather than waiting | |
272 | * for them to time out | |
273 | */ | |
274 | void __exit rxrpc_destroy_all_transports(void) | |
275 | { | |
276 | _enter(""); | |
277 | ||
5873c083 | 278 | rxrpc_transport_expiry = 0; |
17926a79 | 279 | cancel_delayed_work(&rxrpc_transport_reap); |
651350d1 | 280 | rxrpc_queue_delayed_work(&rxrpc_transport_reap, 0); |
17926a79 DH |
281 | |
282 | _leave(""); | |
283 | } |