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 int __inet6_hash(struct sock *sk, struct inet_timewait_sock *tw) 26 { 27 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; 28 int twrefcnt = 0; 29 30 WARN_ON(!sk_unhashed(sk)); 31 32 if (sk->sk_state == TCP_LISTEN) { 33 struct inet_listen_hashbucket *ilb; 34 35 ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)]; 36 spin_lock(&ilb->lock); 37 __sk_nulls_add_node_rcu(sk, &ilb->head); 38 spin_unlock(&ilb->lock); 39 } else { 40 unsigned int hash; 41 struct hlist_nulls_head *list; 42 spinlock_t *lock; 43 44 sk->sk_hash = hash = inet6_sk_ehashfn(sk); 45 list = &inet_ehash_bucket(hashinfo, hash)->chain; 46 lock = inet_ehash_lockp(hashinfo, hash); 47 spin_lock(lock); 48 __sk_nulls_add_node_rcu(sk, list); 49 if (tw) { 50 WARN_ON(sk->sk_hash != tw->tw_hash); 51 twrefcnt = inet_twsk_unhash(tw); 52 } 53 spin_unlock(lock); 54 } 55 56 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 57 return twrefcnt; 58 } 59 EXPORT_SYMBOL(__inet6_hash); 60 61 /* 62 * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so 63 * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM 64 * 65 * The sockhash lock must be held as a reader here. 66 */ 67 struct sock *__inet6_lookup_established(struct net *net, 68 struct inet_hashinfo *hashinfo, 69 const struct in6_addr *saddr, 70 const __be16 sport, 71 const struct in6_addr *daddr, 72 const u16 hnum, 73 const int dif) 74 { 75 struct sock *sk; 76 const struct hlist_nulls_node *node; 77 const __portpair ports = INET_COMBINED_PORTS(sport, hnum); 78 /* Optimize here for direct hit, only listening connections can 79 * have wildcards anyways. 80 */ 81 unsigned int hash = inet6_ehashfn(net, daddr, hnum, saddr, sport); 82 unsigned int slot = hash & hashinfo->ehash_mask; 83 struct inet_ehash_bucket *head = &hashinfo->ehash[slot]; 84 85 86 rcu_read_lock(); 87 begin: 88 sk_nulls_for_each_rcu(sk, node, &head->chain) { 89 /* For IPV6 do the cheaper port and family tests first. */ 90 if (INET6_MATCH(sk, net, hash, saddr, daddr, ports, dif)) { 91 if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt))) 92 goto begintw; 93 if (!INET6_MATCH(sk, net, hash, saddr, daddr, ports, dif)) { 94 sock_put(sk); 95 goto begin; 96 } 97 goto out; 98 } 99 } 100 if (get_nulls_value(node) != slot) 101 goto begin; 102 103 begintw: 104 /* Must check for a TIME_WAIT'er before going to listener hash. */ 105 sk_nulls_for_each_rcu(sk, node, &head->twchain) { 106 if (INET6_TW_MATCH(sk, net, hash, saddr, daddr, ports, dif)) { 107 if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt))) { 108 sk = NULL; 109 goto out; 110 } 111 if (!INET6_TW_MATCH(sk, net, hash, saddr, daddr, ports, dif)) { 112 sock_put(sk); 113 goto begintw; 114 } 115 goto out; 116 } 117 } 118 if (get_nulls_value(node) != slot) 119 goto begintw; 120 sk = NULL; 121 out: 122 rcu_read_unlock(); 123 return sk; 124 } 125 EXPORT_SYMBOL(__inet6_lookup_established); 126 127 static int inline compute_score(struct sock *sk, struct net *net, 128 const unsigned short hnum, 129 const struct in6_addr *daddr, 130 const int dif) 131 { 132 int score = -1; 133 134 if (net_eq(sock_net(sk), net) && inet_sk(sk)->inet_num == hnum && 135 sk->sk_family == PF_INET6) { 136 const struct ipv6_pinfo *np = inet6_sk(sk); 137 138 score = 1; 139 if (!ipv6_addr_any(&np->rcv_saddr)) { 140 if (!ipv6_addr_equal(&np->rcv_saddr, daddr)) 141 return -1; 142 score++; 143 } 144 if (sk->sk_bound_dev_if) { 145 if (sk->sk_bound_dev_if != dif) 146 return -1; 147 score++; 148 } 149 } 150 return score; 151 } 152 153 struct sock *inet6_lookup_listener(struct net *net, 154 struct inet_hashinfo *hashinfo, const struct in6_addr *daddr, 155 const unsigned short hnum, const int dif) 156 { 157 struct sock *sk; 158 const struct hlist_nulls_node *node; 159 struct sock *result; 160 int score, hiscore; 161 unsigned int hash = inet_lhashfn(net, hnum); 162 struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash]; 163 164 rcu_read_lock(); 165 begin: 166 result = NULL; 167 hiscore = -1; 168 sk_nulls_for_each(sk, node, &ilb->head) { 169 score = compute_score(sk, net, hnum, daddr, dif); 170 if (score > hiscore) { 171 hiscore = score; 172 result = sk; 173 } 174 } 175 /* 176 * if the nulls value we got at the end of this lookup is 177 * not the expected one, we must restart lookup. 178 * We probably met an item that was moved to another chain. 179 */ 180 if (get_nulls_value(node) != hash + LISTENING_NULLS_BASE) 181 goto begin; 182 if (result) { 183 if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt))) 184 result = NULL; 185 else if (unlikely(compute_score(result, net, hnum, daddr, 186 dif) < hiscore)) { 187 sock_put(result); 188 goto begin; 189 } 190 } 191 rcu_read_unlock(); 192 return result; 193 } 194 195 EXPORT_SYMBOL_GPL(inet6_lookup_listener); 196 197 struct sock *inet6_lookup(struct net *net, struct inet_hashinfo *hashinfo, 198 const struct in6_addr *saddr, const __be16 sport, 199 const struct in6_addr *daddr, const __be16 dport, 200 const int dif) 201 { 202 struct sock *sk; 203 204 local_bh_disable(); 205 sk = __inet6_lookup(net, hashinfo, saddr, sport, daddr, ntohs(dport), dif); 206 local_bh_enable(); 207 208 return sk; 209 } 210 211 EXPORT_SYMBOL_GPL(inet6_lookup); 212 213 static int __inet6_check_established(struct inet_timewait_death_row *death_row, 214 struct sock *sk, const __u16 lport, 215 struct inet_timewait_sock **twp) 216 { 217 struct inet_hashinfo *hinfo = death_row->hashinfo; 218 struct inet_sock *inet = inet_sk(sk); 219 const struct ipv6_pinfo *np = inet6_sk(sk); 220 const struct in6_addr *daddr = &np->rcv_saddr; 221 const struct in6_addr *saddr = &np->daddr; 222 const int dif = sk->sk_bound_dev_if; 223 const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport); 224 struct net *net = sock_net(sk); 225 const unsigned int hash = inet6_ehashfn(net, daddr, lport, saddr, 226 inet->inet_dport); 227 struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash); 228 spinlock_t *lock = inet_ehash_lockp(hinfo, hash); 229 struct sock *sk2; 230 const struct hlist_nulls_node *node; 231 struct inet_timewait_sock *tw; 232 int twrefcnt = 0; 233 234 spin_lock(lock); 235 236 /* Check TIME-WAIT sockets first. */ 237 sk_nulls_for_each(sk2, node, &head->twchain) { 238 tw = inet_twsk(sk2); 239 240 if (INET6_TW_MATCH(sk2, net, hash, saddr, daddr, ports, dif)) { 241 if (twsk_unique(sk, sk2, twp)) 242 goto unique; 243 else 244 goto not_unique; 245 } 246 } 247 tw = NULL; 248 249 /* And established part... */ 250 sk_nulls_for_each(sk2, node, &head->chain) { 251 if (INET6_MATCH(sk2, net, hash, saddr, daddr, ports, dif)) 252 goto not_unique; 253 } 254 255 unique: 256 /* Must record num and sport now. Otherwise we will see 257 * in hash table socket with a funny identity. */ 258 inet->inet_num = lport; 259 inet->inet_sport = htons(lport); 260 sk->sk_hash = hash; 261 WARN_ON(!sk_unhashed(sk)); 262 __sk_nulls_add_node_rcu(sk, &head->chain); 263 if (tw) { 264 twrefcnt = inet_twsk_unhash(tw); 265 NET_INC_STATS_BH(net, LINUX_MIB_TIMEWAITRECYCLED); 266 } 267 spin_unlock(lock); 268 if (twrefcnt) 269 inet_twsk_put(tw); 270 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 271 272 if (twp) { 273 *twp = tw; 274 } else if (tw) { 275 /* Silly. Should hash-dance instead... */ 276 inet_twsk_deschedule(tw, death_row); 277 278 inet_twsk_put(tw); 279 } 280 return 0; 281 282 not_unique: 283 spin_unlock(lock); 284 return -EADDRNOTAVAIL; 285 } 286 287 static inline u32 inet6_sk_port_offset(const struct sock *sk) 288 { 289 const struct inet_sock *inet = inet_sk(sk); 290 const struct ipv6_pinfo *np = inet6_sk(sk); 291 return secure_ipv6_port_ephemeral(np->rcv_saddr.s6_addr32, 292 np->daddr.s6_addr32, 293 inet->inet_dport); 294 } 295 296 int inet6_hash_connect(struct inet_timewait_death_row *death_row, 297 struct sock *sk) 298 { 299 return __inet_hash_connect(death_row, sk, inet6_sk_port_offset(sk), 300 __inet6_check_established, __inet6_hash); 301 } 302 303 EXPORT_SYMBOL_GPL(inet6_hash_connect); 304