[TCP]: Fix zero port problem in IPv6
[linux-2.6.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/config.h>
18 #include <linux/module.h>
19 #include <linux/random.h>
20
21 #include <net/inet_connection_sock.h>
22 #include <net/inet_hashtables.h>
23 #include <net/inet6_hashtables.h>
24 #include <net/ip.h>
25
26 struct sock *inet6_lookup_listener(struct inet_hashinfo *hashinfo,
27                                    const struct in6_addr *daddr,
28                                    const unsigned short hnum, const int dif)
29 {
30         struct sock *sk;
31         const struct hlist_node *node;
32         struct sock *result = NULL;
33         int score, hiscore = 0;
34
35         read_lock(&hashinfo->lhash_lock);
36         sk_for_each(sk, node, &hashinfo->listening_hash[inet_lhashfn(hnum)]) {
37                 if (inet_sk(sk)->num == hnum && sk->sk_family == PF_INET6) {
38                         const struct ipv6_pinfo *np = inet6_sk(sk);
39                         
40                         score = 1;
41                         if (!ipv6_addr_any(&np->rcv_saddr)) {
42                                 if (!ipv6_addr_equal(&np->rcv_saddr, daddr))
43                                         continue;
44                                 score++;
45                         }
46                         if (sk->sk_bound_dev_if) {
47                                 if (sk->sk_bound_dev_if != dif)
48                                         continue;
49                                 score++;
50                         }
51                         if (score == 3) {
52                                 result = sk;
53                                 break;
54                         }
55                         if (score > hiscore) {
56                                 hiscore = score;
57                                 result = sk;
58                         }
59                 }
60         }
61         if (result)
62                 sock_hold(result);
63         read_unlock(&hashinfo->lhash_lock);
64         return result;
65 }
66
67 EXPORT_SYMBOL_GPL(inet6_lookup_listener);
68
69 struct sock *inet6_lookup(struct inet_hashinfo *hashinfo,
70                           const struct in6_addr *saddr, const u16 sport,
71                           const struct in6_addr *daddr, const u16 dport,
72                           const int dif)
73 {
74         struct sock *sk;
75
76         local_bh_disable();
77         sk = __inet6_lookup(hashinfo, saddr, sport, daddr, ntohs(dport), dif);
78         local_bh_enable();
79
80         return sk;
81 }
82
83 EXPORT_SYMBOL_GPL(inet6_lookup);
84
85 static int __inet6_check_established(struct inet_timewait_death_row *death_row,
86                                      struct sock *sk, const __u16 lport,
87                                      struct inet_timewait_sock **twp)
88 {
89         struct inet_hashinfo *hinfo = death_row->hashinfo;
90         struct inet_sock *inet = inet_sk(sk);
91         const struct ipv6_pinfo *np = inet6_sk(sk);
92         const struct in6_addr *daddr = &np->rcv_saddr;
93         const struct in6_addr *saddr = &np->daddr;
94         const int dif = sk->sk_bound_dev_if;
95         const u32 ports = INET_COMBINED_PORTS(inet->dport, lport);
96         const unsigned int hash = inet6_ehashfn(daddr, inet->num, saddr,
97                                                 inet->dport);
98         struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
99         struct sock *sk2;
100         const struct hlist_node *node;
101         struct inet_timewait_sock *tw;
102
103         prefetch(head->chain.first);
104         write_lock(&head->lock);
105
106         /* Check TIME-WAIT sockets first. */
107         sk_for_each(sk2, node, &(head + hinfo->ehash_size)->chain) {
108                 const struct inet6_timewait_sock *tw6 = inet6_twsk(sk2);
109
110                 tw = inet_twsk(sk2);
111
112                 if(*((__u32 *)&(tw->tw_dport)) == ports          &&
113                    sk2->sk_family              == PF_INET6       &&
114                    ipv6_addr_equal(&tw6->tw_v6_daddr, saddr)     &&
115                    ipv6_addr_equal(&tw6->tw_v6_rcv_saddr, daddr) &&
116                    sk2->sk_bound_dev_if == sk->sk_bound_dev_if) {
117                         if (twsk_unique(sk, sk2, twp))
118                                 goto unique;
119                         else
120                                 goto not_unique;
121                 }
122         }
123         tw = NULL;
124
125         /* And established part... */
126         sk_for_each(sk2, node, &head->chain) {
127                 if (INET6_MATCH(sk2, hash, saddr, daddr, ports, dif))
128                         goto not_unique;
129         }
130
131 unique:
132         /* Must record num and sport now. Otherwise we will see
133          * in hash table socket with a funny identity. */
134         inet->num = lport;
135         inet->sport = htons(lport);
136         BUG_TRAP(sk_unhashed(sk));
137         __sk_add_node(sk, &head->chain);
138         sk->sk_hash = hash;
139         sock_prot_inc_use(sk->sk_prot);
140         write_unlock(&head->lock);
141
142         if (twp != NULL) {
143                 *twp = tw;
144                 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
145         } else if (tw != NULL) {
146                 /* Silly. Should hash-dance instead... */
147                 inet_twsk_deschedule(tw, death_row);
148                 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
149
150                 inet_twsk_put(tw);
151         }
152         return 0;
153
154 not_unique:
155         write_unlock(&head->lock);
156         return -EADDRNOTAVAIL;
157 }
158
159 static inline u32 inet6_sk_port_offset(const struct sock *sk)
160 {
161         const struct inet_sock *inet = inet_sk(sk);
162         const struct ipv6_pinfo *np = inet6_sk(sk);
163         return secure_ipv6_port_ephemeral(np->rcv_saddr.s6_addr32,
164                                           np->daddr.s6_addr32,
165                                           inet->dport);
166 }
167
168 int inet6_hash_connect(struct inet_timewait_death_row *death_row,
169                        struct sock *sk)
170 {
171         struct inet_hashinfo *hinfo = death_row->hashinfo;
172         const unsigned short snum = inet_sk(sk)->num;
173         struct inet_bind_hashbucket *head;
174         struct inet_bind_bucket *tb;
175         int ret;
176
177         if (snum == 0) {
178                 const int low = sysctl_local_port_range[0];
179                 const int high = sysctl_local_port_range[1];
180                 const int range = high - low;
181                 int i, port;
182                 static u32 hint;
183                 const u32 offset = hint + inet6_sk_port_offset(sk);
184                 struct hlist_node *node;
185                 struct inet_timewait_sock *tw = NULL;
186
187                 local_bh_disable();
188                 for (i = 1; i <= range; i++) {
189                         port = low + (i + offset) % range;
190                         head = &hinfo->bhash[inet_bhashfn(port, hinfo->bhash_size)];
191                         spin_lock(&head->lock);
192
193                         /* Does not bother with rcv_saddr checks,
194                          * because the established check is already
195                          * unique enough.
196                          */
197                         inet_bind_bucket_for_each(tb, node, &head->chain) {
198                                 if (tb->port == port) {
199                                         BUG_TRAP(!hlist_empty(&tb->owners));
200                                         if (tb->fastreuse >= 0)
201                                                 goto next_port;
202                                         if (!__inet6_check_established(death_row,
203                                                                        sk, port,
204                                                                        &tw))
205                                                 goto ok;
206                                         goto next_port;
207                                 }
208                         }
209
210                         tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
211                                                      head, port);
212                         if (!tb) {
213                                 spin_unlock(&head->lock);
214                                 break;
215                         }
216                         tb->fastreuse = -1;
217                         goto ok;
218
219                 next_port:
220                         spin_unlock(&head->lock);
221                 }
222                 local_bh_enable();
223
224                 return -EADDRNOTAVAIL;
225
226 ok:
227                 hint += i;
228
229                 /* Head lock still held and bh's disabled */
230                 inet_bind_hash(sk, tb, port);
231                 if (sk_unhashed(sk)) {
232                         inet_sk(sk)->sport = htons(port);
233                         __inet6_hash(hinfo, sk);
234                 }
235                 spin_unlock(&head->lock);
236
237                 if (tw) {
238                         inet_twsk_deschedule(tw, death_row);
239                         inet_twsk_put(tw);
240                 }
241
242                 ret = 0;
243                 goto out;
244         }
245
246         head = &hinfo->bhash[inet_bhashfn(snum, hinfo->bhash_size)];
247         tb   = inet_csk(sk)->icsk_bind_hash;
248         spin_lock_bh(&head->lock);
249
250         if (sk_head(&tb->owners) == sk && sk->sk_bind_node.next == NULL) {
251                 __inet6_hash(hinfo, sk);
252                 spin_unlock_bh(&head->lock);
253                 return 0;
254         } else {
255                 spin_unlock(&head->lock);
256                 /* No definite answer... Walk to established hash table */
257                 ret = __inet6_check_established(death_row, sk, snum, NULL);
258 out:
259                 local_bh_enable();
260                 return ret;
261         }
262 }
263
264 EXPORT_SYMBOL_GPL(inet6_hash_connect);