c0c8d2d176823a74cf7d6db3bcf5cb4c4ab32ccc
[linux-3.10.git] / net / ipv6 / inet6_hashtables.c
1 /*
2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
3  *              operating system.  INET is implemented using the BSD Socket
4  *              interface as the means of communication with the user level.
5  *
6  *              Generic INET6 transport hashtables
7  *
8  * Authors:     Lotsa people, from code originally in tcp, generalised here
9  *              by Arnaldo Carvalho de Melo <acme@mandriva.com>
10  *
11  *      This program is free software; you can redistribute it and/or
12  *      modify it under the terms of the GNU General Public License
13  *      as published by the Free Software Foundation; either version
14  *      2 of the License, or (at your option) any later version.
15  */
16
17 #include <linux/module.h>
18 #include <linux/random.h>
19
20 #include <net/inet_connection_sock.h>
21 #include <net/inet_hashtables.h>
22 #include <net/inet6_hashtables.h>
23 #include <net/ip.h>
24
25 void __inet6_hash(struct sock *sk)
26 {
27         struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
28         struct hlist_head *list;
29         rwlock_t *lock;
30
31         BUG_TRAP(sk_unhashed(sk));
32
33         if (sk->sk_state == TCP_LISTEN) {
34                 list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
35                 lock = &hashinfo->lhash_lock;
36                 inet_listen_wlock(hashinfo);
37         } else {
38                 unsigned int hash;
39                 sk->sk_hash = hash = inet6_sk_ehashfn(sk);
40                 list = &inet_ehash_bucket(hashinfo, hash)->chain;
41                 lock = inet_ehash_lockp(hashinfo, hash);
42                 write_lock(lock);
43         }
44
45         __sk_add_node(sk, list);
46         sock_prot_inuse_add(sk->sk_prot, 1);
47         write_unlock(lock);
48 }
49 EXPORT_SYMBOL(__inet6_hash);
50
51 /*
52  * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so
53  * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM
54  *
55  * The sockhash lock must be held as a reader here.
56  */
57 struct sock *__inet6_lookup_established(struct net *net,
58                                         struct inet_hashinfo *hashinfo,
59                                            const struct in6_addr *saddr,
60                                            const __be16 sport,
61                                            const struct in6_addr *daddr,
62                                            const u16 hnum,
63                                            const int dif)
64 {
65         struct sock *sk;
66         const struct hlist_node *node;
67         const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
68         /* Optimize here for direct hit, only listening connections can
69          * have wildcards anyways.
70          */
71         unsigned int hash = inet6_ehashfn(daddr, hnum, saddr, sport);
72         struct inet_ehash_bucket *head = inet_ehash_bucket(hashinfo, hash);
73         rwlock_t *lock = inet_ehash_lockp(hashinfo, hash);
74
75         prefetch(head->chain.first);
76         read_lock(lock);
77         sk_for_each(sk, node, &head->chain) {
78                 /* For IPV6 do the cheaper port and family tests first. */
79                 if (INET6_MATCH(sk, net, hash, saddr, daddr, ports, dif))
80                         goto hit; /* You sunk my battleship! */
81         }
82         /* Must check for a TIME_WAIT'er before going to listener hash. */
83         sk_for_each(sk, node, &head->twchain) {
84                 if (INET6_TW_MATCH(sk, net, hash, saddr, daddr, ports, dif))
85                         goto hit;
86         }
87         read_unlock(lock);
88         return NULL;
89
90 hit:
91         sock_hold(sk);
92         read_unlock(lock);
93         return sk;
94 }
95 EXPORT_SYMBOL(__inet6_lookup_established);
96
97 struct sock *inet6_lookup_listener(struct net *net,
98                 struct inet_hashinfo *hashinfo, const struct in6_addr *daddr,
99                 const unsigned short hnum, const int dif)
100 {
101         struct sock *sk;
102         const struct hlist_node *node;
103         struct sock *result = NULL;
104         int score, hiscore = 0;
105
106         read_lock(&hashinfo->lhash_lock);
107         sk_for_each(sk, node, &hashinfo->listening_hash[inet_lhashfn(hnum)]) {
108                 if (sk->sk_net == net && inet_sk(sk)->num == hnum &&
109                                 sk->sk_family == PF_INET6) {
110                         const struct ipv6_pinfo *np = inet6_sk(sk);
111
112                         score = 1;
113                         if (!ipv6_addr_any(&np->rcv_saddr)) {
114                                 if (!ipv6_addr_equal(&np->rcv_saddr, daddr))
115                                         continue;
116                                 score++;
117                         }
118                         if (sk->sk_bound_dev_if) {
119                                 if (sk->sk_bound_dev_if != dif)
120                                         continue;
121                                 score++;
122                         }
123                         if (score == 3) {
124                                 result = sk;
125                                 break;
126                         }
127                         if (score > hiscore) {
128                                 hiscore = score;
129                                 result = sk;
130                         }
131                 }
132         }
133         if (result)
134                 sock_hold(result);
135         read_unlock(&hashinfo->lhash_lock);
136         return result;
137 }
138
139 EXPORT_SYMBOL_GPL(inet6_lookup_listener);
140
141 struct sock *inet6_lookup(struct net *net, struct inet_hashinfo *hashinfo,
142                           const struct in6_addr *saddr, const __be16 sport,
143                           const struct in6_addr *daddr, const __be16 dport,
144                           const int dif)
145 {
146         struct sock *sk;
147
148         local_bh_disable();
149         sk = __inet6_lookup(net, hashinfo, saddr, sport, daddr, ntohs(dport), dif);
150         local_bh_enable();
151
152         return sk;
153 }
154
155 EXPORT_SYMBOL_GPL(inet6_lookup);
156
157 static int __inet6_check_established(struct inet_timewait_death_row *death_row,
158                                      struct sock *sk, const __u16 lport,
159                                      struct inet_timewait_sock **twp)
160 {
161         struct inet_hashinfo *hinfo = death_row->hashinfo;
162         struct inet_sock *inet = inet_sk(sk);
163         const struct ipv6_pinfo *np = inet6_sk(sk);
164         const struct in6_addr *daddr = &np->rcv_saddr;
165         const struct in6_addr *saddr = &np->daddr;
166         const int dif = sk->sk_bound_dev_if;
167         const __portpair ports = INET_COMBINED_PORTS(inet->dport, lport);
168         const unsigned int hash = inet6_ehashfn(daddr, lport, saddr,
169                                                 inet->dport);
170         struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
171         rwlock_t *lock = inet_ehash_lockp(hinfo, hash);
172         struct sock *sk2;
173         const struct hlist_node *node;
174         struct inet_timewait_sock *tw;
175         struct net *net = sk->sk_net;
176
177         prefetch(head->chain.first);
178         write_lock(lock);
179
180         /* Check TIME-WAIT sockets first. */
181         sk_for_each(sk2, node, &head->twchain) {
182                 tw = inet_twsk(sk2);
183
184                 if (INET6_TW_MATCH(sk2, net, hash, saddr, daddr, ports, dif)) {
185                         if (twsk_unique(sk, sk2, twp))
186                                 goto unique;
187                         else
188                                 goto not_unique;
189                 }
190         }
191         tw = NULL;
192
193         /* And established part... */
194         sk_for_each(sk2, node, &head->chain) {
195                 if (INET6_MATCH(sk2, net, hash, saddr, daddr, ports, dif))
196                         goto not_unique;
197         }
198
199 unique:
200         /* Must record num and sport now. Otherwise we will see
201          * in hash table socket with a funny identity. */
202         inet->num = lport;
203         inet->sport = htons(lport);
204         BUG_TRAP(sk_unhashed(sk));
205         __sk_add_node(sk, &head->chain);
206         sk->sk_hash = hash;
207         sock_prot_inuse_add(sk->sk_prot, 1);
208         write_unlock(lock);
209
210         if (twp != NULL) {
211                 *twp = tw;
212                 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
213         } else if (tw != NULL) {
214                 /* Silly. Should hash-dance instead... */
215                 inet_twsk_deschedule(tw, death_row);
216                 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
217
218                 inet_twsk_put(tw);
219         }
220         return 0;
221
222 not_unique:
223         write_unlock(lock);
224         return -EADDRNOTAVAIL;
225 }
226
227 static inline u32 inet6_sk_port_offset(const struct sock *sk)
228 {
229         const struct inet_sock *inet = inet_sk(sk);
230         const struct ipv6_pinfo *np = inet6_sk(sk);
231         return secure_ipv6_port_ephemeral(np->rcv_saddr.s6_addr32,
232                                           np->daddr.s6_addr32,
233                                           inet->dport);
234 }
235
236 int inet6_hash_connect(struct inet_timewait_death_row *death_row,
237                        struct sock *sk)
238 {
239         return __inet_hash_connect(death_row, sk, inet6_sk_port_offset(sk),
240                         __inet6_check_established, __inet6_hash);
241 }
242
243 EXPORT_SYMBOL_GPL(inet6_hash_connect);