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be6e6707 | 1 | /* RxRPC remote transport endpoint record management |
17926a79 | 2 | * |
be6e6707 | 3 | * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved. |
17926a79 DH |
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 | ||
9b6d5398 JP |
12 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
13 | ||
17926a79 DH |
14 | #include <linux/module.h> |
15 | #include <linux/net.h> | |
16 | #include <linux/skbuff.h> | |
17 | #include <linux/udp.h> | |
18 | #include <linux/in.h> | |
5a0e3ad6 | 19 | #include <linux/slab.h> |
be6e6707 | 20 | #include <linux/hashtable.h> |
17926a79 DH |
21 | #include <net/sock.h> |
22 | #include <net/af_rxrpc.h> | |
23 | #include <net/ip.h> | |
224711df | 24 | #include <net/route.h> |
17926a79 DH |
25 | #include "ar-internal.h" |
26 | ||
be6e6707 DH |
27 | static DEFINE_HASHTABLE(rxrpc_peer_hash, 10); |
28 | static DEFINE_SPINLOCK(rxrpc_peer_hash_lock); | |
17926a79 | 29 | |
be6e6707 DH |
30 | /* |
31 | * Hash a peer key. | |
32 | */ | |
33 | static unsigned long rxrpc_peer_hash_key(struct rxrpc_local *local, | |
34 | const struct sockaddr_rxrpc *srx) | |
35 | { | |
36 | const u16 *p; | |
37 | unsigned int i, size; | |
38 | unsigned long hash_key; | |
39 | ||
40 | _enter(""); | |
41 | ||
42 | hash_key = (unsigned long)local / __alignof__(*local); | |
43 | hash_key += srx->transport_type; | |
44 | hash_key += srx->transport_len; | |
45 | hash_key += srx->transport.family; | |
46 | ||
47 | switch (srx->transport.family) { | |
48 | case AF_INET: | |
49 | hash_key += (u16 __force)srx->transport.sin.sin_port; | |
50 | size = sizeof(srx->transport.sin.sin_addr); | |
51 | p = (u16 *)&srx->transport.sin.sin_addr; | |
52 | break; | |
2f9f9f52 AB |
53 | default: |
54 | WARN(1, "AF_RXRPC: Unsupported transport address family\n"); | |
55 | return 0; | |
be6e6707 DH |
56 | } |
57 | ||
58 | /* Step through the peer address in 16-bit portions for speed */ | |
59 | for (i = 0; i < size; i += sizeof(*p), p++) | |
60 | hash_key += *p; | |
61 | ||
62 | _leave(" 0x%lx", hash_key); | |
63 | return hash_key; | |
64 | } | |
65 | ||
66 | /* | |
67 | * Compare a peer to a key. Return -ve, 0 or +ve to indicate less than, same | |
68 | * or greater than. | |
69 | * | |
70 | * Unfortunately, the primitives in linux/hashtable.h don't allow for sorted | |
71 | * buckets and mid-bucket insertion, so we don't make full use of this | |
72 | * information at this point. | |
73 | */ | |
74 | static long rxrpc_peer_cmp_key(const struct rxrpc_peer *peer, | |
75 | struct rxrpc_local *local, | |
76 | const struct sockaddr_rxrpc *srx, | |
77 | unsigned long hash_key) | |
78 | { | |
79 | long diff; | |
80 | ||
81 | diff = ((peer->hash_key - hash_key) ?: | |
82 | ((unsigned long)peer->local - (unsigned long)local) ?: | |
83 | (peer->srx.transport_type - srx->transport_type) ?: | |
84 | (peer->srx.transport_len - srx->transport_len) ?: | |
85 | (peer->srx.transport.family - srx->transport.family)); | |
86 | if (diff != 0) | |
87 | return diff; | |
88 | ||
89 | switch (srx->transport.family) { | |
90 | case AF_INET: | |
91 | return ((u16 __force)peer->srx.transport.sin.sin_port - | |
92 | (u16 __force)srx->transport.sin.sin_port) ?: | |
93 | memcmp(&peer->srx.transport.sin.sin_addr, | |
94 | &srx->transport.sin.sin_addr, | |
95 | sizeof(struct in_addr)); | |
96 | default: | |
97 | BUG(); | |
98 | } | |
99 | } | |
100 | ||
101 | /* | |
102 | * Look up a remote transport endpoint for the specified address using RCU. | |
103 | */ | |
104 | static struct rxrpc_peer *__rxrpc_lookup_peer_rcu( | |
105 | struct rxrpc_local *local, | |
106 | const struct sockaddr_rxrpc *srx, | |
107 | unsigned long hash_key) | |
108 | { | |
109 | struct rxrpc_peer *peer; | |
110 | ||
111 | hash_for_each_possible_rcu(rxrpc_peer_hash, peer, hash_link, hash_key) { | |
112 | if (rxrpc_peer_cmp_key(peer, local, srx, hash_key) == 0) { | |
113 | if (atomic_read(&peer->usage) == 0) | |
114 | return NULL; | |
115 | return peer; | |
116 | } | |
117 | } | |
118 | ||
119 | return NULL; | |
120 | } | |
121 | ||
122 | /* | |
123 | * Look up a remote transport endpoint for the specified address using RCU. | |
124 | */ | |
125 | struct rxrpc_peer *rxrpc_lookup_peer_rcu(struct rxrpc_local *local, | |
126 | const struct sockaddr_rxrpc *srx) | |
127 | { | |
128 | struct rxrpc_peer *peer; | |
129 | unsigned long hash_key = rxrpc_peer_hash_key(local, srx); | |
130 | ||
131 | peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key); | |
132 | if (peer) { | |
133 | switch (srx->transport.family) { | |
134 | case AF_INET: | |
135 | _net("PEER %d {%d,%u,%pI4+%hu}", | |
136 | peer->debug_id, | |
137 | peer->srx.transport_type, | |
138 | peer->srx.transport.family, | |
139 | &peer->srx.transport.sin.sin_addr, | |
140 | ntohs(peer->srx.transport.sin.sin_port)); | |
141 | break; | |
142 | } | |
143 | ||
144 | _leave(" = %p {u=%d}", peer, atomic_read(&peer->usage)); | |
145 | } | |
146 | return peer; | |
147 | } | |
17926a79 | 148 | |
224711df DH |
149 | /* |
150 | * assess the MTU size for the network interface through which this peer is | |
151 | * reached | |
152 | */ | |
153 | static void rxrpc_assess_MTU_size(struct rxrpc_peer *peer) | |
154 | { | |
155 | struct rtable *rt; | |
31e4543d | 156 | struct flowi4 fl4; |
224711df DH |
157 | |
158 | peer->if_mtu = 1500; | |
159 | ||
31e4543d | 160 | rt = ip_route_output_ports(&init_net, &fl4, NULL, |
78fbfd8a DM |
161 | peer->srx.transport.sin.sin_addr.s_addr, 0, |
162 | htons(7000), htons(7001), | |
163 | IPPROTO_UDP, 0, 0); | |
b23dd4fe DM |
164 | if (IS_ERR(rt)) { |
165 | _leave(" [route err %ld]", PTR_ERR(rt)); | |
224711df DH |
166 | return; |
167 | } | |
168 | ||
d8d1f30b CG |
169 | peer->if_mtu = dst_mtu(&rt->dst); |
170 | dst_release(&rt->dst); | |
224711df | 171 | |
a6a62b69 | 172 | _leave(" [if_mtu %u]", peer->if_mtu); |
224711df DH |
173 | } |
174 | ||
17926a79 | 175 | /* |
be6e6707 | 176 | * Allocate a peer. |
17926a79 | 177 | */ |
be6e6707 | 178 | struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp) |
17926a79 DH |
179 | { |
180 | struct rxrpc_peer *peer; | |
181 | ||
182 | _enter(""); | |
183 | ||
184 | peer = kzalloc(sizeof(struct rxrpc_peer), gfp); | |
185 | if (peer) { | |
be6e6707 DH |
186 | atomic_set(&peer->usage, 1); |
187 | peer->local = local; | |
f66d7490 DH |
188 | INIT_HLIST_HEAD(&peer->error_targets); |
189 | INIT_WORK(&peer->error_distributor, | |
190 | &rxrpc_peer_error_distributor); | |
aa390bbe DH |
191 | peer->service_conns = RB_ROOT; |
192 | rwlock_init(&peer->conn_lock); | |
17926a79 | 193 | spin_lock_init(&peer->lock); |
17926a79 | 194 | peer->debug_id = atomic_inc_return(&rxrpc_debug_id); |
be6e6707 DH |
195 | } |
196 | ||
197 | _leave(" = %p", peer); | |
198 | return peer; | |
199 | } | |
200 | ||
201 | /* | |
202 | * Set up a new peer. | |
203 | */ | |
204 | static struct rxrpc_peer *rxrpc_create_peer(struct rxrpc_local *local, | |
205 | struct sockaddr_rxrpc *srx, | |
206 | unsigned long hash_key, | |
207 | gfp_t gfp) | |
208 | { | |
209 | struct rxrpc_peer *peer; | |
210 | ||
211 | _enter(""); | |
212 | ||
213 | peer = rxrpc_alloc_peer(local, gfp); | |
214 | if (peer) { | |
215 | peer->hash_key = hash_key; | |
17926a79 DH |
216 | memcpy(&peer->srx, srx, sizeof(*srx)); |
217 | ||
224711df DH |
218 | rxrpc_assess_MTU_size(peer); |
219 | peer->mtu = peer->if_mtu; | |
17926a79 DH |
220 | |
221 | if (srx->transport.family == AF_INET) { | |
222 | peer->hdrsize = sizeof(struct iphdr); | |
223 | switch (srx->transport_type) { | |
224 | case SOCK_DGRAM: | |
225 | peer->hdrsize += sizeof(struct udphdr); | |
226 | break; | |
227 | default: | |
228 | BUG(); | |
229 | break; | |
230 | } | |
231 | } else { | |
232 | BUG(); | |
233 | } | |
234 | ||
0d12f8a4 | 235 | peer->hdrsize += sizeof(struct rxrpc_wire_header); |
17926a79 DH |
236 | peer->maxdata = peer->mtu - peer->hdrsize; |
237 | } | |
238 | ||
239 | _leave(" = %p", peer); | |
240 | return peer; | |
241 | } | |
242 | ||
243 | /* | |
244 | * obtain a remote transport endpoint for the specified address | |
245 | */ | |
be6e6707 DH |
246 | struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_local *local, |
247 | struct sockaddr_rxrpc *srx, gfp_t gfp) | |
17926a79 DH |
248 | { |
249 | struct rxrpc_peer *peer, *candidate; | |
be6e6707 | 250 | unsigned long hash_key = rxrpc_peer_hash_key(local, srx); |
17926a79 | 251 | |
21454aaa | 252 | _enter("{%d,%d,%pI4+%hu}", |
17926a79 DH |
253 | srx->transport_type, |
254 | srx->transport_len, | |
21454aaa | 255 | &srx->transport.sin.sin_addr, |
17926a79 DH |
256 | ntohs(srx->transport.sin.sin_port)); |
257 | ||
258 | /* search the peer list first */ | |
be6e6707 DH |
259 | rcu_read_lock(); |
260 | peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key); | |
261 | if (peer && !rxrpc_get_peer_maybe(peer)) | |
262 | peer = NULL; | |
263 | rcu_read_unlock(); | |
264 | ||
265 | if (!peer) { | |
266 | /* The peer is not yet present in hash - create a candidate | |
267 | * for a new record and then redo the search. | |
268 | */ | |
269 | candidate = rxrpc_create_peer(local, srx, hash_key, gfp); | |
270 | if (!candidate) { | |
271 | _leave(" = NULL [nomem]"); | |
272 | return NULL; | |
273 | } | |
17926a79 | 274 | |
be6e6707 | 275 | spin_lock(&rxrpc_peer_hash_lock); |
17926a79 | 276 | |
be6e6707 DH |
277 | /* Need to check that we aren't racing with someone else */ |
278 | peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key); | |
279 | if (peer && !rxrpc_get_peer_maybe(peer)) | |
280 | peer = NULL; | |
281 | if (!peer) | |
282 | hash_add_rcu(rxrpc_peer_hash, | |
283 | &candidate->hash_link, hash_key); | |
17926a79 | 284 | |
be6e6707 | 285 | spin_unlock(&rxrpc_peer_hash_lock); |
17926a79 | 286 | |
be6e6707 DH |
287 | if (peer) |
288 | kfree(candidate); | |
289 | else | |
290 | peer = candidate; | |
291 | } | |
17926a79 | 292 | |
be6e6707 | 293 | _net("PEER %d {%d,%pI4+%hu}", |
17926a79 DH |
294 | peer->debug_id, |
295 | peer->srx.transport_type, | |
21454aaa | 296 | &peer->srx.transport.sin.sin_addr, |
17926a79 DH |
297 | ntohs(peer->srx.transport.sin.sin_port)); |
298 | ||
be6e6707 | 299 | _leave(" = %p {u=%d}", peer, atomic_read(&peer->usage)); |
17926a79 | 300 | return peer; |
17926a79 DH |
301 | } |
302 | ||
303 | /* | |
be6e6707 | 304 | * Discard a ref on a remote peer record. |
17926a79 | 305 | */ |
be6e6707 | 306 | void __rxrpc_put_peer(struct rxrpc_peer *peer) |
17926a79 | 307 | { |
f66d7490 | 308 | ASSERT(hlist_empty(&peer->error_targets)); |
17926a79 | 309 | |
be6e6707 DH |
310 | spin_lock(&rxrpc_peer_hash_lock); |
311 | hash_del_rcu(&peer->hash_link); | |
312 | spin_unlock(&rxrpc_peer_hash_lock); | |
17926a79 | 313 | |
be6e6707 | 314 | kfree_rcu(peer, rcu); |
17926a79 | 315 | } |