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 29 WARN_ON(!sk_unhashed(sk)); 30 31 if (sk->sk_state == TCP_LISTEN) { 32 struct inet_listen_hashbucket *ilb; 33 34 ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)]; 35 spin_lock(&ilb->lock); 36 __sk_nulls_add_node_rcu(sk, &ilb->head); 37 spin_unlock(&ilb->lock); 38 } else { 39 unsigned int hash; 40 struct hlist_nulls_head *list; 41 spinlock_t *lock; 42 43 sk->sk_hash = hash = inet6_sk_ehashfn(sk); 44 list = &inet_ehash_bucket(hashinfo, hash)->chain; 45 lock = inet_ehash_lockp(hashinfo, hash); 46 spin_lock(lock); 47 __sk_nulls_add_node_rcu(sk, list); 48 spin_unlock(lock); 49 } 50 51 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 52 } 53 EXPORT_SYMBOL(__inet6_hash); 54 55 /* 56 * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so 57 * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM 58 * 59 * The sockhash lock must be held as a reader here. 60 */ 61 struct sock *__inet6_lookup_established(struct net *net, 62 struct inet_hashinfo *hashinfo, 63 const struct in6_addr *saddr, 64 const __be16 sport, 65 const struct in6_addr *daddr, 66 const u16 hnum, 67 const int dif) 68 { 69 struct sock *sk; 70 const struct hlist_nulls_node *node; 71 const __portpair ports = INET_COMBINED_PORTS(sport, hnum); 72 /* Optimize here for direct hit, only listening connections can 73 * have wildcards anyways. 74 */ 75 unsigned int hash = inet6_ehashfn(net, daddr, hnum, saddr, sport); 76 unsigned int slot = hash & (hashinfo->ehash_size - 1); 77 struct inet_ehash_bucket *head = &hashinfo->ehash[slot]; 78 79 80 rcu_read_lock(); 81 begin: 82 sk_nulls_for_each_rcu(sk, node, &head->chain) { 83 /* For IPV6 do the cheaper port and family tests first. */ 84 if (INET6_MATCH(sk, net, hash, saddr, daddr, ports, dif)) { 85 if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt))) 86 goto begintw; 87 if (!INET6_MATCH(sk, net, hash, saddr, daddr, ports, dif)) { 88 sock_put(sk); 89 goto begin; 90 } 91 goto out; 92 } 93 } 94 if (get_nulls_value(node) != slot) 95 goto begin; 96 97 begintw: 98 /* Must check for a TIME_WAIT'er before going to listener hash. */ 99 sk_nulls_for_each_rcu(sk, node, &head->twchain) { 100 if (INET6_TW_MATCH(sk, net, hash, saddr, daddr, ports, dif)) { 101 if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt))) { 102 sk = NULL; 103 goto out; 104 } 105 if (!INET6_TW_MATCH(sk, net, hash, saddr, daddr, ports, dif)) { 106 sock_put(sk); 107 goto begintw; 108 } 109 goto out; 110 } 111 } 112 if (get_nulls_value(node) != slot) 113 goto begintw; 114 sk = NULL; 115 out: 116 rcu_read_unlock(); 117 return sk; 118 } 119 EXPORT_SYMBOL(__inet6_lookup_established); 120 121 static int inline compute_score(struct sock *sk, struct net *net, 122 const unsigned short hnum, 123 const struct in6_addr *daddr, 124 const int dif) 125 { 126 int score = -1; 127 128 if (net_eq(sock_net(sk), net) && inet_sk(sk)->num == hnum && 129 sk->sk_family == PF_INET6) { 130 const struct ipv6_pinfo *np = inet6_sk(sk); 131 132 score = 1; 133 if (!ipv6_addr_any(&np->rcv_saddr)) { 134 if (!ipv6_addr_equal(&np->rcv_saddr, daddr)) 135 return -1; 136 score++; 137 } 138 if (sk->sk_bound_dev_if) { 139 if (sk->sk_bound_dev_if != dif) 140 return -1; 141 score++; 142 } 143 } 144 return score; 145 } 146 147 struct sock *inet6_lookup_listener(struct net *net, 148 struct inet_hashinfo *hashinfo, const struct in6_addr *daddr, 149 const unsigned short hnum, const int dif) 150 { 151 struct sock *sk; 152 const struct hlist_nulls_node *node; 153 struct sock *result; 154 int score, hiscore; 155 unsigned int hash = inet_lhashfn(net, hnum); 156 struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash]; 157 158 rcu_read_lock(); 159 begin: 160 result = NULL; 161 hiscore = -1; 162 sk_nulls_for_each(sk, node, &ilb->head) { 163 score = compute_score(sk, net, hnum, daddr, dif); 164 if (score > hiscore) { 165 hiscore = score; 166 result = sk; 167 } 168 } 169 /* 170 * if the nulls value we got at the end of this lookup is 171 * not the expected one, we must restart lookup. 172 * We probably met an item that was moved to another chain. 173 */ 174 if (get_nulls_value(node) != hash + LISTENING_NULLS_BASE) 175 goto begin; 176 if (result) { 177 if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt))) 178 result = NULL; 179 else if (unlikely(compute_score(result, net, hnum, daddr, 180 dif) < hiscore)) { 181 sock_put(result); 182 goto begin; 183 } 184 } 185 rcu_read_unlock(); 186 return result; 187 } 188 189 EXPORT_SYMBOL_GPL(inet6_lookup_listener); 190 191 struct sock *inet6_lookup(struct net *net, struct inet_hashinfo *hashinfo, 192 const struct in6_addr *saddr, const __be16 sport, 193 const struct in6_addr *daddr, const __be16 dport, 194 const int dif) 195 { 196 struct sock *sk; 197 198 local_bh_disable(); 199 sk = __inet6_lookup(net, hashinfo, saddr, sport, daddr, ntohs(dport), dif); 200 local_bh_enable(); 201 202 return sk; 203 } 204 205 EXPORT_SYMBOL_GPL(inet6_lookup); 206 207 static int __inet6_check_established(struct inet_timewait_death_row *death_row, 208 struct sock *sk, const __u16 lport, 209 struct inet_timewait_sock **twp) 210 { 211 struct inet_hashinfo *hinfo = death_row->hashinfo; 212 struct inet_sock *inet = inet_sk(sk); 213 const struct ipv6_pinfo *np = inet6_sk(sk); 214 const struct in6_addr *daddr = &np->rcv_saddr; 215 const struct in6_addr *saddr = &np->daddr; 216 const int dif = sk->sk_bound_dev_if; 217 const __portpair ports = INET_COMBINED_PORTS(inet->dport, lport); 218 struct net *net = sock_net(sk); 219 const unsigned int hash = inet6_ehashfn(net, daddr, lport, saddr, 220 inet->dport); 221 struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash); 222 spinlock_t *lock = inet_ehash_lockp(hinfo, hash); 223 struct sock *sk2; 224 const struct hlist_nulls_node *node; 225 struct inet_timewait_sock *tw; 226 227 spin_lock(lock); 228 229 /* Check TIME-WAIT sockets first. */ 230 sk_nulls_for_each(sk2, node, &head->twchain) { 231 tw = inet_twsk(sk2); 232 233 if (INET6_TW_MATCH(sk2, net, hash, saddr, daddr, ports, dif)) { 234 if (twsk_unique(sk, sk2, twp)) 235 goto unique; 236 else 237 goto not_unique; 238 } 239 } 240 tw = NULL; 241 242 /* And established part... */ 243 sk_nulls_for_each(sk2, node, &head->chain) { 244 if (INET6_MATCH(sk2, net, hash, saddr, daddr, ports, dif)) 245 goto not_unique; 246 } 247 248 unique: 249 /* Must record num and sport now. Otherwise we will see 250 * in hash table socket with a funny identity. */ 251 inet->num = lport; 252 inet->sport = htons(lport); 253 WARN_ON(!sk_unhashed(sk)); 254 __sk_nulls_add_node_rcu(sk, &head->chain); 255 sk->sk_hash = hash; 256 spin_unlock(lock); 257 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 258 259 if (twp != NULL) { 260 *twp = tw; 261 NET_INC_STATS_BH(net, LINUX_MIB_TIMEWAITRECYCLED); 262 } else if (tw != NULL) { 263 /* Silly. Should hash-dance instead... */ 264 inet_twsk_deschedule(tw, death_row); 265 NET_INC_STATS_BH(net, LINUX_MIB_TIMEWAITRECYCLED); 266 267 inet_twsk_put(tw); 268 } 269 return 0; 270 271 not_unique: 272 spin_unlock(lock); 273 return -EADDRNOTAVAIL; 274 } 275 276 static inline u32 inet6_sk_port_offset(const struct sock *sk) 277 { 278 const struct inet_sock *inet = inet_sk(sk); 279 const struct ipv6_pinfo *np = inet6_sk(sk); 280 return secure_ipv6_port_ephemeral(np->rcv_saddr.s6_addr32, 281 np->daddr.s6_addr32, 282 inet->dport); 283 } 284 285 int inet6_hash_connect(struct inet_timewait_death_row *death_row, 286 struct sock *sk) 287 { 288 return __inet_hash_connect(death_row, sk, inet6_sk_port_offset(sk), 289 __inet6_check_established, __inet6_hash); 290 } 291 292 EXPORT_SYMBOL_GPL(inet6_hash_connect); 293