[NETNS]: Add namespace parameter to ip_route_output_key.
[linux-2.6.git] / net / rxrpc / ar-peer.c
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>
19 #include <net/sock.h>
20 #include <net/af_rxrpc.h>
21 #include <net/ip.h>
22 #include <net/route.h>
23 #include "ar-internal.h"
24
25 static LIST_HEAD(rxrpc_peers);
26 static DEFINE_RWLOCK(rxrpc_peer_lock);
27 static DECLARE_WAIT_QUEUE_HEAD(rxrpc_peer_wq);
28
29 static void rxrpc_destroy_peer(struct work_struct *work);
30
31 /*
32  * assess the MTU size for the network interface through which this peer is
33  * reached
34  */
35 static void rxrpc_assess_MTU_size(struct rxrpc_peer *peer)
36 {
37         struct rtable *rt;
38         struct flowi fl;
39         int ret;
40
41         peer->if_mtu = 1500;
42
43         memset(&fl, 0, sizeof(fl));
44
45         switch (peer->srx.transport.family) {
46         case AF_INET:
47                 fl.oif = 0;
48                 fl.proto = IPPROTO_UDP,
49                 fl.nl_u.ip4_u.saddr = 0;
50                 fl.nl_u.ip4_u.daddr = peer->srx.transport.sin.sin_addr.s_addr;
51                 fl.nl_u.ip4_u.tos = 0;
52                 /* assume AFS.CM talking to AFS.FS */
53                 fl.uli_u.ports.sport = htons(7001);
54                 fl.uli_u.ports.dport = htons(7000);
55                 break;
56         default:
57                 BUG();
58         }
59
60         ret = ip_route_output_key(&init_net, &rt, &fl);
61         if (ret < 0) {
62                 _leave(" [route err %d]", ret);
63                 return;
64         }
65
66         peer->if_mtu = dst_mtu(&rt->u.dst);
67         dst_release(&rt->u.dst);
68
69         _leave(" [if_mtu %u]", peer->if_mtu);
70 }
71
72 /*
73  * allocate a new peer
74  */
75 static struct rxrpc_peer *rxrpc_alloc_peer(struct sockaddr_rxrpc *srx,
76                                            gfp_t gfp)
77 {
78         struct rxrpc_peer *peer;
79
80         _enter("");
81
82         peer = kzalloc(sizeof(struct rxrpc_peer), gfp);
83         if (peer) {
84                 INIT_WORK(&peer->destroyer, &rxrpc_destroy_peer);
85                 INIT_LIST_HEAD(&peer->link);
86                 INIT_LIST_HEAD(&peer->error_targets);
87                 spin_lock_init(&peer->lock);
88                 atomic_set(&peer->usage, 1);
89                 peer->debug_id = atomic_inc_return(&rxrpc_debug_id);
90                 memcpy(&peer->srx, srx, sizeof(*srx));
91
92                 rxrpc_assess_MTU_size(peer);
93                 peer->mtu = peer->if_mtu;
94
95                 if (srx->transport.family == AF_INET) {
96                         peer->hdrsize = sizeof(struct iphdr);
97                         switch (srx->transport_type) {
98                         case SOCK_DGRAM:
99                                 peer->hdrsize += sizeof(struct udphdr);
100                                 break;
101                         default:
102                                 BUG();
103                                 break;
104                         }
105                 } else {
106                         BUG();
107                 }
108
109                 peer->hdrsize += sizeof(struct rxrpc_header);
110                 peer->maxdata = peer->mtu - peer->hdrsize;
111         }
112
113         _leave(" = %p", peer);
114         return peer;
115 }
116
117 /*
118  * obtain a remote transport endpoint for the specified address
119  */
120 struct rxrpc_peer *rxrpc_get_peer(struct sockaddr_rxrpc *srx, gfp_t gfp)
121 {
122         struct rxrpc_peer *peer, *candidate;
123         const char *new = "old";
124         int usage;
125
126         _enter("{%d,%d,%u.%u.%u.%u+%hu}",
127                srx->transport_type,
128                srx->transport_len,
129                NIPQUAD(srx->transport.sin.sin_addr),
130                ntohs(srx->transport.sin.sin_port));
131
132         /* search the peer list first */
133         read_lock_bh(&rxrpc_peer_lock);
134         list_for_each_entry(peer, &rxrpc_peers, link) {
135                 _debug("check PEER %d { u=%d t=%d l=%d }",
136                        peer->debug_id,
137                        atomic_read(&peer->usage),
138                        peer->srx.transport_type,
139                        peer->srx.transport_len);
140
141                 if (atomic_read(&peer->usage) > 0 &&
142                     peer->srx.transport_type == srx->transport_type &&
143                     peer->srx.transport_len == srx->transport_len &&
144                     memcmp(&peer->srx.transport,
145                            &srx->transport,
146                            srx->transport_len) == 0)
147                         goto found_extant_peer;
148         }
149         read_unlock_bh(&rxrpc_peer_lock);
150
151         /* not yet present - create a candidate for a new record and then
152          * redo the search */
153         candidate = rxrpc_alloc_peer(srx, gfp);
154         if (!candidate) {
155                 _leave(" = -ENOMEM");
156                 return ERR_PTR(-ENOMEM);
157         }
158
159         write_lock_bh(&rxrpc_peer_lock);
160
161         list_for_each_entry(peer, &rxrpc_peers, link) {
162                 if (atomic_read(&peer->usage) > 0 &&
163                     peer->srx.transport_type == srx->transport_type &&
164                     peer->srx.transport_len == srx->transport_len &&
165                     memcmp(&peer->srx.transport,
166                            &srx->transport,
167                            srx->transport_len) == 0)
168                         goto found_extant_second;
169         }
170
171         /* we can now add the new candidate to the list */
172         peer = candidate;
173         candidate = NULL;
174
175         list_add_tail(&peer->link, &rxrpc_peers);
176         write_unlock_bh(&rxrpc_peer_lock);
177         new = "new";
178
179 success:
180         _net("PEER %s %d {%d,%u,%u.%u.%u.%u+%hu}",
181              new,
182              peer->debug_id,
183              peer->srx.transport_type,
184              peer->srx.transport.family,
185              NIPQUAD(peer->srx.transport.sin.sin_addr),
186              ntohs(peer->srx.transport.sin.sin_port));
187
188         _leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
189         return peer;
190
191         /* we found the peer in the list immediately */
192 found_extant_peer:
193         usage = atomic_inc_return(&peer->usage);
194         read_unlock_bh(&rxrpc_peer_lock);
195         goto success;
196
197         /* we found the peer on the second time through the list */
198 found_extant_second:
199         usage = atomic_inc_return(&peer->usage);
200         write_unlock_bh(&rxrpc_peer_lock);
201         kfree(candidate);
202         goto success;
203 }
204
205 /*
206  * find the peer associated with a packet
207  */
208 struct rxrpc_peer *rxrpc_find_peer(struct rxrpc_local *local,
209                                    __be32 addr, __be16 port)
210 {
211         struct rxrpc_peer *peer;
212
213         _enter("");
214
215         /* search the peer list */
216         read_lock_bh(&rxrpc_peer_lock);
217
218         if (local->srx.transport.family == AF_INET &&
219             local->srx.transport_type == SOCK_DGRAM
220             ) {
221                 list_for_each_entry(peer, &rxrpc_peers, link) {
222                         if (atomic_read(&peer->usage) > 0 &&
223                             peer->srx.transport_type == SOCK_DGRAM &&
224                             peer->srx.transport.family == AF_INET &&
225                             peer->srx.transport.sin.sin_port == port &&
226                             peer->srx.transport.sin.sin_addr.s_addr == addr)
227                                 goto found_UDP_peer;
228                 }
229
230                 goto new_UDP_peer;
231         }
232
233         read_unlock_bh(&rxrpc_peer_lock);
234         _leave(" = -EAFNOSUPPORT");
235         return ERR_PTR(-EAFNOSUPPORT);
236
237 found_UDP_peer:
238         _net("Rx UDP DGRAM from peer %d", peer->debug_id);
239         atomic_inc(&peer->usage);
240         read_unlock_bh(&rxrpc_peer_lock);
241         _leave(" = %p", peer);
242         return peer;
243
244 new_UDP_peer:
245         _net("Rx UDP DGRAM from NEW peer %d", peer->debug_id);
246         read_unlock_bh(&rxrpc_peer_lock);
247         _leave(" = -EBUSY [new]");
248         return ERR_PTR(-EBUSY);
249 }
250
251 /*
252  * release a remote transport endpoint
253  */
254 void rxrpc_put_peer(struct rxrpc_peer *peer)
255 {
256         _enter("%p{u=%d}", peer, atomic_read(&peer->usage));
257
258         ASSERTCMP(atomic_read(&peer->usage), >, 0);
259
260         if (likely(!atomic_dec_and_test(&peer->usage))) {
261                 _leave(" [in use]");
262                 return;
263         }
264
265         rxrpc_queue_work(&peer->destroyer);
266         _leave("");
267 }
268
269 /*
270  * destroy a remote transport endpoint
271  */
272 static void rxrpc_destroy_peer(struct work_struct *work)
273 {
274         struct rxrpc_peer *peer =
275                 container_of(work, struct rxrpc_peer, destroyer);
276
277         _enter("%p{%d}", peer, atomic_read(&peer->usage));
278
279         write_lock_bh(&rxrpc_peer_lock);
280         list_del(&peer->link);
281         write_unlock_bh(&rxrpc_peer_lock);
282
283         _net("DESTROY PEER %d", peer->debug_id);
284         kfree(peer);
285
286         if (list_empty(&rxrpc_peers))
287                 wake_up_all(&rxrpc_peer_wq);
288         _leave("");
289 }
290
291 /*
292  * preemptively destroy all the peer records from a transport endpoint rather
293  * than waiting for them to time out
294  */
295 void __exit rxrpc_destroy_all_peers(void)
296 {
297         DECLARE_WAITQUEUE(myself,current);
298
299         _enter("");
300
301         /* we simply have to wait for them to go away */
302         if (!list_empty(&rxrpc_peers)) {
303                 set_current_state(TASK_UNINTERRUPTIBLE);
304                 add_wait_queue(&rxrpc_peer_wq, &myself);
305
306                 while (!list_empty(&rxrpc_peers)) {
307                         schedule();
308                         set_current_state(TASK_UNINTERRUPTIBLE);
309                 }
310
311                 remove_wait_queue(&rxrpc_peer_wq, &myself);
312                 set_current_state(TASK_RUNNING);
313         }
314
315         _leave("");
316 }