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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); | |
0d12f8a4 | 54 | trans->conn_idcounter = peer->srx.srx_service << 16; |
17926a79 DH |
55 | trans->debug_id = atomic_inc_return(&rxrpc_debug_id); |
56 | ||
57 | if (peer->srx.transport.family == AF_INET) { | |
58 | switch (peer->srx.transport_type) { | |
59 | case SOCK_DGRAM: | |
60 | INIT_WORK(&trans->error_handler, | |
61 | rxrpc_UDP_error_handler); | |
62 | break; | |
63 | default: | |
64 | BUG(); | |
65 | break; | |
66 | } | |
67 | } else { | |
68 | BUG(); | |
69 | } | |
70 | } | |
71 | ||
72 | _leave(" = %p", trans); | |
73 | return trans; | |
74 | } | |
75 | ||
76 | /* | |
77 | * obtain a transport session for the nominated endpoints | |
78 | */ | |
79 | struct rxrpc_transport *rxrpc_get_transport(struct rxrpc_local *local, | |
80 | struct rxrpc_peer *peer, | |
81 | gfp_t gfp) | |
82 | { | |
83 | struct rxrpc_transport *trans, *candidate; | |
84 | const char *new = "old"; | |
85 | int usage; | |
86 | ||
21454aaa HH |
87 | _enter("{%pI4+%hu},{%pI4+%hu},", |
88 | &local->srx.transport.sin.sin_addr, | |
17926a79 | 89 | ntohs(local->srx.transport.sin.sin_port), |
21454aaa | 90 | &peer->srx.transport.sin.sin_addr, |
17926a79 DH |
91 | ntohs(peer->srx.transport.sin.sin_port)); |
92 | ||
93 | /* search the transport list first */ | |
94 | read_lock_bh(&rxrpc_transport_lock); | |
95 | list_for_each_entry(trans, &rxrpc_transports, link) { | |
96 | if (trans->local == local && trans->peer == peer) | |
97 | goto found_extant_transport; | |
98 | } | |
99 | read_unlock_bh(&rxrpc_transport_lock); | |
100 | ||
101 | /* not yet present - create a candidate for a new record and then | |
102 | * redo the search */ | |
103 | candidate = rxrpc_alloc_transport(local, peer, gfp); | |
104 | if (!candidate) { | |
105 | _leave(" = -ENOMEM"); | |
106 | return ERR_PTR(-ENOMEM); | |
107 | } | |
108 | ||
109 | write_lock_bh(&rxrpc_transport_lock); | |
110 | ||
111 | list_for_each_entry(trans, &rxrpc_transports, link) { | |
112 | if (trans->local == local && trans->peer == peer) | |
113 | goto found_extant_second; | |
114 | } | |
115 | ||
116 | /* we can now add the new candidate to the list */ | |
117 | trans = candidate; | |
118 | candidate = NULL; | |
ed84cadb | 119 | usage = atomic_read(&trans->usage); |
17926a79 DH |
120 | |
121 | rxrpc_get_local(trans->local); | |
122 | atomic_inc(&trans->peer->usage); | |
123 | list_add_tail(&trans->link, &rxrpc_transports); | |
124 | write_unlock_bh(&rxrpc_transport_lock); | |
125 | new = "new"; | |
126 | ||
127 | success: | |
128 | _net("TRANSPORT %s %d local %d -> peer %d", | |
129 | new, | |
130 | trans->debug_id, | |
131 | trans->local->debug_id, | |
132 | trans->peer->debug_id); | |
133 | ||
ed84cadb | 134 | _leave(" = %p {u=%d}", trans, usage); |
17926a79 DH |
135 | return trans; |
136 | ||
137 | /* we found the transport in the list immediately */ | |
138 | found_extant_transport: | |
139 | usage = atomic_inc_return(&trans->usage); | |
140 | read_unlock_bh(&rxrpc_transport_lock); | |
141 | goto success; | |
142 | ||
143 | /* we found the transport on the second time through the list */ | |
144 | found_extant_second: | |
145 | usage = atomic_inc_return(&trans->usage); | |
146 | write_unlock_bh(&rxrpc_transport_lock); | |
147 | kfree(candidate); | |
148 | goto success; | |
149 | } | |
150 | ||
151 | /* | |
152 | * find the transport connecting two endpoints | |
153 | */ | |
154 | struct rxrpc_transport *rxrpc_find_transport(struct rxrpc_local *local, | |
155 | struct rxrpc_peer *peer) | |
156 | { | |
157 | struct rxrpc_transport *trans; | |
158 | ||
21454aaa HH |
159 | _enter("{%pI4+%hu},{%pI4+%hu},", |
160 | &local->srx.transport.sin.sin_addr, | |
17926a79 | 161 | ntohs(local->srx.transport.sin.sin_port), |
21454aaa | 162 | &peer->srx.transport.sin.sin_addr, |
17926a79 DH |
163 | ntohs(peer->srx.transport.sin.sin_port)); |
164 | ||
165 | /* search the transport list */ | |
166 | read_lock_bh(&rxrpc_transport_lock); | |
167 | ||
168 | list_for_each_entry(trans, &rxrpc_transports, link) { | |
169 | if (trans->local == local && trans->peer == peer) | |
170 | goto found_extant_transport; | |
171 | } | |
172 | ||
173 | read_unlock_bh(&rxrpc_transport_lock); | |
174 | _leave(" = NULL"); | |
175 | return NULL; | |
176 | ||
177 | found_extant_transport: | |
178 | atomic_inc(&trans->usage); | |
179 | read_unlock_bh(&rxrpc_transport_lock); | |
180 | _leave(" = %p", trans); | |
181 | return trans; | |
182 | } | |
183 | ||
184 | /* | |
185 | * release a transport session | |
186 | */ | |
187 | void rxrpc_put_transport(struct rxrpc_transport *trans) | |
188 | { | |
189 | _enter("%p{u=%d}", trans, atomic_read(&trans->usage)); | |
190 | ||
191 | ASSERTCMP(atomic_read(&trans->usage), >, 0); | |
192 | ||
22a3f9a2 | 193 | trans->put_time = ktime_get_seconds(); |
50aab54f | 194 | if (unlikely(atomic_dec_and_test(&trans->usage))) { |
17926a79 DH |
195 | _debug("zombie"); |
196 | /* let the reaper determine the timeout to avoid a race with | |
197 | * overextending the timeout if the reaper is running at the | |
198 | * same time */ | |
651350d1 | 199 | rxrpc_queue_delayed_work(&rxrpc_transport_reap, 0); |
50aab54f | 200 | } |
17926a79 DH |
201 | _leave(""); |
202 | } | |
203 | ||
204 | /* | |
205 | * clean up a transport session | |
206 | */ | |
207 | static void rxrpc_cleanup_transport(struct rxrpc_transport *trans) | |
208 | { | |
209 | _net("DESTROY TRANS %d", trans->debug_id); | |
210 | ||
211 | rxrpc_purge_queue(&trans->error_queue); | |
212 | ||
213 | rxrpc_put_local(trans->local); | |
214 | rxrpc_put_peer(trans->peer); | |
215 | kfree(trans); | |
216 | } | |
217 | ||
218 | /* | |
219 | * reap dead transports that have passed their expiry date | |
220 | */ | |
221 | static void rxrpc_transport_reaper(struct work_struct *work) | |
222 | { | |
223 | struct rxrpc_transport *trans, *_p; | |
224 | unsigned long now, earliest, reap_time; | |
225 | ||
226 | LIST_HEAD(graveyard); | |
227 | ||
228 | _enter(""); | |
229 | ||
22a3f9a2 | 230 | now = ktime_get_seconds(); |
17926a79 DH |
231 | earliest = ULONG_MAX; |
232 | ||
233 | /* extract all the transports that have been dead too long */ | |
234 | write_lock_bh(&rxrpc_transport_lock); | |
235 | list_for_each_entry_safe(trans, _p, &rxrpc_transports, link) { | |
236 | _debug("reap TRANS %d { u=%d t=%ld }", | |
237 | trans->debug_id, atomic_read(&trans->usage), | |
238 | (long) now - (long) trans->put_time); | |
239 | ||
240 | if (likely(atomic_read(&trans->usage) > 0)) | |
241 | continue; | |
242 | ||
5873c083 | 243 | reap_time = trans->put_time + rxrpc_transport_expiry; |
17926a79 DH |
244 | if (reap_time <= now) |
245 | list_move_tail(&trans->link, &graveyard); | |
246 | else if (reap_time < earliest) | |
247 | earliest = reap_time; | |
248 | } | |
249 | write_unlock_bh(&rxrpc_transport_lock); | |
250 | ||
251 | if (earliest != ULONG_MAX) { | |
252 | _debug("reschedule reaper %ld", (long) earliest - now); | |
253 | ASSERTCMP(earliest, >, now); | |
651350d1 DH |
254 | rxrpc_queue_delayed_work(&rxrpc_transport_reap, |
255 | (earliest - now) * HZ); | |
17926a79 DH |
256 | } |
257 | ||
258 | /* then destroy all those pulled out */ | |
259 | while (!list_empty(&graveyard)) { | |
260 | trans = list_entry(graveyard.next, struct rxrpc_transport, | |
261 | link); | |
262 | list_del_init(&trans->link); | |
263 | ||
264 | ASSERTCMP(atomic_read(&trans->usage), ==, 0); | |
265 | rxrpc_cleanup_transport(trans); | |
266 | } | |
267 | ||
268 | _leave(""); | |
269 | } | |
270 | ||
271 | /* | |
272 | * preemptively destroy all the transport session records rather than waiting | |
273 | * for them to time out | |
274 | */ | |
275 | void __exit rxrpc_destroy_all_transports(void) | |
276 | { | |
277 | _enter(""); | |
278 | ||
5873c083 | 279 | rxrpc_transport_expiry = 0; |
17926a79 | 280 | cancel_delayed_work(&rxrpc_transport_reap); |
651350d1 | 281 | rxrpc_queue_delayed_work(&rxrpc_transport_reap, 0); |
17926a79 DH |
282 | |
283 | _leave(""); | |
284 | } |