ipv6,mcast: always hold idev->lock before mca_lock
[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/secure_seq.h>
24 #include <net/ip.h>
25
26 int __inet6_hash(struct sock *sk, struct inet_timewait_sock *tw)
27 {
28         struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
29         int twrefcnt = 0;
30
31         WARN_ON(!sk_unhashed(sk));
32
33         if (sk->sk_state == TCP_LISTEN) {
34                 struct inet_listen_hashbucket *ilb;
35
36                 ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
37                 spin_lock(&ilb->lock);
38                 __sk_nulls_add_node_rcu(sk, &ilb->head);
39                 spin_unlock(&ilb->lock);
40         } else {
41                 unsigned int hash;
42                 struct hlist_nulls_head *list;
43                 spinlock_t *lock;
44
45                 sk->sk_hash = hash = inet6_sk_ehashfn(sk);
46                 list = &inet_ehash_bucket(hashinfo, hash)->chain;
47                 lock = inet_ehash_lockp(hashinfo, hash);
48                 spin_lock(lock);
49                 __sk_nulls_add_node_rcu(sk, list);
50                 if (tw) {
51                         WARN_ON(sk->sk_hash != tw->tw_hash);
52                         twrefcnt = inet_twsk_unhash(tw);
53                 }
54                 spin_unlock(lock);
55         }
56
57         sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
58         return twrefcnt;
59 }
60 EXPORT_SYMBOL(__inet6_hash);
61
62 /*
63  * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so
64  * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM
65  *
66  * The sockhash lock must be held as a reader here.
67  */
68 struct sock *__inet6_lookup_established(struct net *net,
69                                         struct inet_hashinfo *hashinfo,
70                                            const struct in6_addr *saddr,
71                                            const __be16 sport,
72                                            const struct in6_addr *daddr,
73                                            const u16 hnum,
74                                            const int dif)
75 {
76         struct sock *sk;
77         const struct hlist_nulls_node *node;
78         const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
79         /* Optimize here for direct hit, only listening connections can
80          * have wildcards anyways.
81          */
82         unsigned int hash = inet6_ehashfn(net, daddr, hnum, saddr, sport);
83         unsigned int slot = hash & hashinfo->ehash_mask;
84         struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
85
86
87         rcu_read_lock();
88 begin:
89         sk_nulls_for_each_rcu(sk, node, &head->chain) {
90                 if (sk->sk_hash != hash)
91                         continue;
92                 if (likely(INET6_MATCH(sk, net, saddr, daddr, ports, dif))) {
93                         if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt)))
94                                 goto begintw;
95                         if (unlikely(!INET6_MATCH(sk, net, saddr, daddr,
96                                                   ports, dif))) {
97                                 sock_put(sk);
98                                 goto begin;
99                         }
100                 goto out;
101                 }
102         }
103         if (get_nulls_value(node) != slot)
104                 goto begin;
105
106 begintw:
107         /* Must check for a TIME_WAIT'er before going to listener hash. */
108         sk_nulls_for_each_rcu(sk, node, &head->twchain) {
109                 if (sk->sk_hash != hash)
110                         continue;
111                 if (likely(INET6_TW_MATCH(sk, net, saddr, daddr,
112                                           ports, dif))) {
113                         if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt))) {
114                                 sk = NULL;
115                                 goto out;
116                         }
117                         if (unlikely(!INET6_TW_MATCH(sk, net, saddr, daddr,
118                                                      ports, dif))) {
119                                 sock_put(sk);
120                                 goto begintw;
121                         }
122                         goto out;
123                 }
124         }
125         if (get_nulls_value(node) != slot)
126                 goto begintw;
127         sk = NULL;
128 out:
129         rcu_read_unlock();
130         return sk;
131 }
132 EXPORT_SYMBOL(__inet6_lookup_established);
133
134 static inline int compute_score(struct sock *sk, struct net *net,
135                                 const unsigned short hnum,
136                                 const struct in6_addr *daddr,
137                                 const int dif)
138 {
139         int score = -1;
140
141         if (net_eq(sock_net(sk), net) && inet_sk(sk)->inet_num == hnum &&
142             sk->sk_family == PF_INET6) {
143                 const struct ipv6_pinfo *np = inet6_sk(sk);
144
145                 score = 1;
146                 if (!ipv6_addr_any(&np->rcv_saddr)) {
147                         if (!ipv6_addr_equal(&np->rcv_saddr, daddr))
148                                 return -1;
149                         score++;
150                 }
151                 if (sk->sk_bound_dev_if) {
152                         if (sk->sk_bound_dev_if != dif)
153                                 return -1;
154                         score++;
155                 }
156         }
157         return score;
158 }
159
160 struct sock *inet6_lookup_listener(struct net *net,
161                 struct inet_hashinfo *hashinfo, const struct in6_addr *saddr,
162                 const __be16 sport, const struct in6_addr *daddr,
163                 const unsigned short hnum, const int dif)
164 {
165         struct sock *sk;
166         const struct hlist_nulls_node *node;
167         struct sock *result;
168         int score, hiscore, matches = 0, reuseport = 0;
169         u32 phash = 0;
170         unsigned int hash = inet_lhashfn(net, hnum);
171         struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];
172
173         rcu_read_lock();
174 begin:
175         result = NULL;
176         hiscore = 0;
177         sk_nulls_for_each(sk, node, &ilb->head) {
178                 score = compute_score(sk, net, hnum, daddr, dif);
179                 if (score > hiscore) {
180                         hiscore = score;
181                         result = sk;
182                         reuseport = sk->sk_reuseport;
183                         if (reuseport) {
184                                 phash = inet6_ehashfn(net, daddr, hnum,
185                                                       saddr, sport);
186                                 matches = 1;
187                         }
188                 } else if (score == hiscore && reuseport) {
189                         matches++;
190                         if (((u64)phash * matches) >> 32 == 0)
191                                 result = sk;
192                         phash = next_pseudo_random32(phash);
193                 }
194         }
195         /*
196          * if the nulls value we got at the end of this lookup is
197          * not the expected one, we must restart lookup.
198          * We probably met an item that was moved to another chain.
199          */
200         if (get_nulls_value(node) != hash + LISTENING_NULLS_BASE)
201                 goto begin;
202         if (result) {
203                 if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
204                         result = NULL;
205                 else if (unlikely(compute_score(result, net, hnum, daddr,
206                                   dif) < hiscore)) {
207                         sock_put(result);
208                         goto begin;
209                 }
210         }
211         rcu_read_unlock();
212         return result;
213 }
214
215 EXPORT_SYMBOL_GPL(inet6_lookup_listener);
216
217 struct sock *inet6_lookup(struct net *net, struct inet_hashinfo *hashinfo,
218                           const struct in6_addr *saddr, const __be16 sport,
219                           const struct in6_addr *daddr, const __be16 dport,
220                           const int dif)
221 {
222         struct sock *sk;
223
224         local_bh_disable();
225         sk = __inet6_lookup(net, hashinfo, saddr, sport, daddr, ntohs(dport), dif);
226         local_bh_enable();
227
228         return sk;
229 }
230
231 EXPORT_SYMBOL_GPL(inet6_lookup);
232
233 static int __inet6_check_established(struct inet_timewait_death_row *death_row,
234                                      struct sock *sk, const __u16 lport,
235                                      struct inet_timewait_sock **twp)
236 {
237         struct inet_hashinfo *hinfo = death_row->hashinfo;
238         struct inet_sock *inet = inet_sk(sk);
239         const struct ipv6_pinfo *np = inet6_sk(sk);
240         const struct in6_addr *daddr = &np->rcv_saddr;
241         const struct in6_addr *saddr = &np->daddr;
242         const int dif = sk->sk_bound_dev_if;
243         const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
244         struct net *net = sock_net(sk);
245         const unsigned int hash = inet6_ehashfn(net, daddr, lport, saddr,
246                                                 inet->inet_dport);
247         struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
248         spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
249         struct sock *sk2;
250         const struct hlist_nulls_node *node;
251         struct inet_timewait_sock *tw;
252         int twrefcnt = 0;
253
254         spin_lock(lock);
255
256         /* Check TIME-WAIT sockets first. */
257         sk_nulls_for_each(sk2, node, &head->twchain) {
258                 if (sk2->sk_hash != hash)
259                         continue;
260
261                 if (likely(INET6_TW_MATCH(sk2, net, saddr, daddr,
262                                           ports, dif))) {
263                         tw = inet_twsk(sk2);
264                         if (twsk_unique(sk, sk2, twp))
265                                 goto unique;
266                         else
267                                 goto not_unique;
268                 }
269         }
270         tw = NULL;
271
272         /* And established part... */
273         sk_nulls_for_each(sk2, node, &head->chain) {
274                 if (sk2->sk_hash != hash)
275                         continue;
276                 if (likely(INET6_MATCH(sk2, net, saddr, daddr, ports, dif)))
277                         goto not_unique;
278         }
279
280 unique:
281         /* Must record num and sport now. Otherwise we will see
282          * in hash table socket with a funny identity. */
283         inet->inet_num = lport;
284         inet->inet_sport = htons(lport);
285         sk->sk_hash = hash;
286         WARN_ON(!sk_unhashed(sk));
287         __sk_nulls_add_node_rcu(sk, &head->chain);
288         if (tw) {
289                 twrefcnt = inet_twsk_unhash(tw);
290                 NET_INC_STATS_BH(net, LINUX_MIB_TIMEWAITRECYCLED);
291         }
292         spin_unlock(lock);
293         if (twrefcnt)
294                 inet_twsk_put(tw);
295         sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
296
297         if (twp) {
298                 *twp = tw;
299         } else if (tw) {
300                 /* Silly. Should hash-dance instead... */
301                 inet_twsk_deschedule(tw, death_row);
302
303                 inet_twsk_put(tw);
304         }
305         return 0;
306
307 not_unique:
308         spin_unlock(lock);
309         return -EADDRNOTAVAIL;
310 }
311
312 static inline u32 inet6_sk_port_offset(const struct sock *sk)
313 {
314         const struct inet_sock *inet = inet_sk(sk);
315         const struct ipv6_pinfo *np = inet6_sk(sk);
316         return secure_ipv6_port_ephemeral(np->rcv_saddr.s6_addr32,
317                                           np->daddr.s6_addr32,
318                                           inet->inet_dport);
319 }
320
321 int inet6_hash_connect(struct inet_timewait_death_row *death_row,
322                        struct sock *sk)
323 {
324         return __inet_hash_connect(death_row, sk, inet6_sk_port_offset(sk),
325                         __inet6_check_established, __inet6_hash);
326 }
327
328 EXPORT_SYMBOL_GPL(inet6_hash_connect);