blob: 92df566930b9a05c23d109cb9e42806698cbb535 [file] [log] [blame]
David Howells17926a72007-04-26 15:48:28 -07001/* 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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090015#include <linux/slab.h>
David Howells17926a72007-04-26 15:48:28 -070016#include <net/sock.h>
17#include <net/af_rxrpc.h>
18#include "ar-internal.h"
19
20static void rxrpc_transport_reaper(struct work_struct *work);
21
22static LIST_HEAD(rxrpc_transports);
23static DEFINE_RWLOCK(rxrpc_transport_lock);
24static unsigned long rxrpc_transport_timeout = 3600 * 24;
25static DECLARE_DELAYED_WORK(rxrpc_transport_reap, rxrpc_transport_reaper);
26
27/*
28 * allocate a new transport session manager
29 */
30static 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 */
74struct 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
Harvey Harrison21454aa2008-10-31 00:54:56 -070082 _enter("{%pI4+%hu},{%pI4+%hu},",
83 &local->srx.transport.sin.sin_addr,
David Howells17926a72007-04-26 15:48:28 -070084 ntohs(local->srx.transport.sin.sin_port),
Harvey Harrison21454aa2008-10-31 00:54:56 -070085 &peer->srx.transport.sin.sin_addr,
David Howells17926a72007-04-26 15:48:28 -070086 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;
David S. Millered84cad2011-05-19 18:51:50 -0400114 usage = atomic_read(&trans->usage);
David Howells17926a72007-04-26 15:48:28 -0700115
116 rxrpc_get_local(trans->local);
117 atomic_inc(&trans->peer->usage);
118 list_add_tail(&trans->link, &rxrpc_transports);
119 write_unlock_bh(&rxrpc_transport_lock);
120 new = "new";
121
122success:
123 _net("TRANSPORT %s %d local %d -> peer %d",
124 new,
125 trans->debug_id,
126 trans->local->debug_id,
127 trans->peer->debug_id);
128
David S. Millered84cad2011-05-19 18:51:50 -0400129 _leave(" = %p {u=%d}", trans, usage);
David Howells17926a72007-04-26 15:48:28 -0700130 return trans;
131
132 /* we found the transport in the list immediately */
133found_extant_transport:
134 usage = atomic_inc_return(&trans->usage);
135 read_unlock_bh(&rxrpc_transport_lock);
136 goto success;
137
138 /* we found the transport on the second time through the list */
139found_extant_second:
140 usage = atomic_inc_return(&trans->usage);
141 write_unlock_bh(&rxrpc_transport_lock);
142 kfree(candidate);
143 goto success;
144}
145
146/*
147 * find the transport connecting two endpoints
148 */
149struct rxrpc_transport *rxrpc_find_transport(struct rxrpc_local *local,
150 struct rxrpc_peer *peer)
151{
152 struct rxrpc_transport *trans;
153
Harvey Harrison21454aa2008-10-31 00:54:56 -0700154 _enter("{%pI4+%hu},{%pI4+%hu},",
155 &local->srx.transport.sin.sin_addr,
David Howells17926a72007-04-26 15:48:28 -0700156 ntohs(local->srx.transport.sin.sin_port),
Harvey Harrison21454aa2008-10-31 00:54:56 -0700157 &peer->srx.transport.sin.sin_addr,
David Howells17926a72007-04-26 15:48:28 -0700158 ntohs(peer->srx.transport.sin.sin_port));
159
160 /* search the transport list */
161 read_lock_bh(&rxrpc_transport_lock);
162
163 list_for_each_entry(trans, &rxrpc_transports, link) {
164 if (trans->local == local && trans->peer == peer)
165 goto found_extant_transport;
166 }
167
168 read_unlock_bh(&rxrpc_transport_lock);
169 _leave(" = NULL");
170 return NULL;
171
172found_extant_transport:
173 atomic_inc(&trans->usage);
174 read_unlock_bh(&rxrpc_transport_lock);
175 _leave(" = %p", trans);
176 return trans;
177}
178
179/*
180 * release a transport session
181 */
182void rxrpc_put_transport(struct rxrpc_transport *trans)
183{
184 _enter("%p{u=%d}", trans, atomic_read(&trans->usage));
185
186 ASSERTCMP(atomic_read(&trans->usage), >, 0);
187
john stultz2c6b47d2007-07-24 17:47:43 -0700188 trans->put_time = get_seconds();
Ilpo Järvinen50aab542008-05-02 16:20:10 -0700189 if (unlikely(atomic_dec_and_test(&trans->usage))) {
David Howells17926a72007-04-26 15:48:28 -0700190 _debug("zombie");
191 /* let the reaper determine the timeout to avoid a race with
192 * overextending the timeout if the reaper is running at the
193 * same time */
David Howells651350d2007-04-26 15:50:17 -0700194 rxrpc_queue_delayed_work(&rxrpc_transport_reap, 0);
Ilpo Järvinen50aab542008-05-02 16:20:10 -0700195 }
David Howells17926a72007-04-26 15:48:28 -0700196 _leave("");
197}
198
199/*
200 * clean up a transport session
201 */
202static void rxrpc_cleanup_transport(struct rxrpc_transport *trans)
203{
204 _net("DESTROY TRANS %d", trans->debug_id);
205
206 rxrpc_purge_queue(&trans->error_queue);
207
208 rxrpc_put_local(trans->local);
209 rxrpc_put_peer(trans->peer);
210 kfree(trans);
211}
212
213/*
214 * reap dead transports that have passed their expiry date
215 */
216static void rxrpc_transport_reaper(struct work_struct *work)
217{
218 struct rxrpc_transport *trans, *_p;
219 unsigned long now, earliest, reap_time;
220
221 LIST_HEAD(graveyard);
222
223 _enter("");
224
john stultz2c6b47d2007-07-24 17:47:43 -0700225 now = get_seconds();
David Howells17926a72007-04-26 15:48:28 -0700226 earliest = ULONG_MAX;
227
228 /* extract all the transports that have been dead too long */
229 write_lock_bh(&rxrpc_transport_lock);
230 list_for_each_entry_safe(trans, _p, &rxrpc_transports, link) {
231 _debug("reap TRANS %d { u=%d t=%ld }",
232 trans->debug_id, atomic_read(&trans->usage),
233 (long) now - (long) trans->put_time);
234
235 if (likely(atomic_read(&trans->usage) > 0))
236 continue;
237
238 reap_time = trans->put_time + rxrpc_transport_timeout;
239 if (reap_time <= now)
240 list_move_tail(&trans->link, &graveyard);
241 else if (reap_time < earliest)
242 earliest = reap_time;
243 }
244 write_unlock_bh(&rxrpc_transport_lock);
245
246 if (earliest != ULONG_MAX) {
247 _debug("reschedule reaper %ld", (long) earliest - now);
248 ASSERTCMP(earliest, >, now);
David Howells651350d2007-04-26 15:50:17 -0700249 rxrpc_queue_delayed_work(&rxrpc_transport_reap,
250 (earliest - now) * HZ);
David Howells17926a72007-04-26 15:48:28 -0700251 }
252
253 /* then destroy all those pulled out */
254 while (!list_empty(&graveyard)) {
255 trans = list_entry(graveyard.next, struct rxrpc_transport,
256 link);
257 list_del_init(&trans->link);
258
259 ASSERTCMP(atomic_read(&trans->usage), ==, 0);
260 rxrpc_cleanup_transport(trans);
261 }
262
263 _leave("");
264}
265
266/*
267 * preemptively destroy all the transport session records rather than waiting
268 * for them to time out
269 */
270void __exit rxrpc_destroy_all_transports(void)
271{
272 _enter("");
273
274 rxrpc_transport_timeout = 0;
275 cancel_delayed_work(&rxrpc_transport_reap);
David Howells651350d2007-04-26 15:50:17 -0700276 rxrpc_queue_delayed_work(&rxrpc_transport_reap, 0);
David Howells17926a72007-04-26 15:48:28 -0700277
278 _leave("");
279}