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 /* For IPV6 do the cheaper port and family tests first. */ 91 if (INET6_MATCH(sk, net, hash, saddr, daddr, ports, dif)) { 92 if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt))) 93 goto begintw; 94 if (!INET6_MATCH(sk, net, hash, saddr, daddr, ports, dif)) { 95 sock_put(sk); 96 goto begin; 97 } 98 goto out; 99 } 100 } 101 if (get_nulls_value(node) != slot) 102 goto begin; 103 104 begintw: 105 /* Must check for a TIME_WAIT'er before going to listener hash. */ 106 sk_nulls_for_each_rcu(sk, node, &head->twchain) { 107 if (INET6_TW_MATCH(sk, net, hash, saddr, daddr, ports, dif)) { 108 if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt))) { 109 sk = NULL; 110 goto out; 111 } 112 if (!INET6_TW_MATCH(sk, net, hash, saddr, daddr, ports, dif)) { 113 sock_put(sk); 114 goto begintw; 115 } 116 goto out; 117 } 118 } 119 if (get_nulls_value(node) != slot) 120 goto begintw; 121 sk = NULL; 122 out: 123 rcu_read_unlock(); 124 return sk; 125 } 126 EXPORT_SYMBOL(__inet6_lookup_established); 127 128 static inline int compute_score(struct sock *sk, struct net *net, 129 const unsigned short hnum, 130 const struct in6_addr *daddr, 131 const int dif) 132 { 133 int score = -1; 134 135 if (net_eq(sock_net(sk), net) && inet_sk(sk)->inet_num == hnum && 136 sk->sk_family == PF_INET6) { 137 const struct ipv6_pinfo *np = inet6_sk(sk); 138 139 score = 1; 140 if (!ipv6_addr_any(&np->rcv_saddr)) { 141 if (!ipv6_addr_equal(&np->rcv_saddr, daddr)) 142 return -1; 143 score++; 144 } 145 if (sk->sk_bound_dev_if) { 146 if (sk->sk_bound_dev_if != dif) 147 return -1; 148 score++; 149 } 150 } 151 return score; 152 } 153 154 struct sock *inet6_lookup_listener(struct net *net, 155 struct inet_hashinfo *hashinfo, const struct in6_addr *daddr, 156 const unsigned short hnum, const int dif) 157 { 158 struct sock *sk; 159 const struct hlist_nulls_node *node; 160 struct sock *result; 161 int score, hiscore; 162 unsigned int hash = inet_lhashfn(net, hnum); 163 struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash]; 164 165 rcu_read_lock(); 166 begin: 167 result = NULL; 168 hiscore = -1; 169 sk_nulls_for_each(sk, node, &ilb->head) { 170 score = compute_score(sk, net, hnum, daddr, dif); 171 if (score > hiscore) { 172 hiscore = score; 173 result = sk; 174 } 175 } 176 /* 177 * if the nulls value we got at the end of this lookup is 178 * not the expected one, we must restart lookup. 179 * We probably met an item that was moved to another chain. 180 */ 181 if (get_nulls_value(node) != hash + LISTENING_NULLS_BASE) 182 goto begin; 183 if (result) { 184 if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt))) 185 result = NULL; 186 else if (unlikely(compute_score(result, net, hnum, daddr, 187 dif) < hiscore)) { 188 sock_put(result); 189 goto begin; 190 } 191 } 192 rcu_read_unlock(); 193 return result; 194 } 195 196 EXPORT_SYMBOL_GPL(inet6_lookup_listener); 197 198 struct sock *inet6_lookup(struct net *net, struct inet_hashinfo *hashinfo, 199 const struct in6_addr *saddr, const __be16 sport, 200 const struct in6_addr *daddr, const __be16 dport, 201 const int dif) 202 { 203 struct sock *sk; 204 205 local_bh_disable(); 206 sk = __inet6_lookup(net, hashinfo, saddr, sport, daddr, ntohs(dport), dif); 207 local_bh_enable(); 208 209 return sk; 210 } 211 212 EXPORT_SYMBOL_GPL(inet6_lookup); 213 214 static int __inet6_check_established(struct inet_timewait_death_row *death_row, 215 struct sock *sk, const __u16 lport, 216 struct inet_timewait_sock **twp) 217 { 218 struct inet_hashinfo *hinfo = death_row->hashinfo; 219 struct inet_sock *inet = inet_sk(sk); 220 const struct ipv6_pinfo *np = inet6_sk(sk); 221 const struct in6_addr *daddr = &np->rcv_saddr; 222 const struct in6_addr *saddr = &np->daddr; 223 const int dif = sk->sk_bound_dev_if; 224 const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport); 225 struct net *net = sock_net(sk); 226 const unsigned int hash = inet6_ehashfn(net, daddr, lport, saddr, 227 inet->inet_dport); 228 struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash); 229 spinlock_t *lock = inet_ehash_lockp(hinfo, hash); 230 struct sock *sk2; 231 const struct hlist_nulls_node *node; 232 struct inet_timewait_sock *tw; 233 int twrefcnt = 0; 234 235 spin_lock(lock); 236 237 /* Check TIME-WAIT sockets first. */ 238 sk_nulls_for_each(sk2, node, &head->twchain) { 239 tw = inet_twsk(sk2); 240 241 if (INET6_TW_MATCH(sk2, net, hash, saddr, daddr, ports, dif)) { 242 if (twsk_unique(sk, sk2, twp)) 243 goto unique; 244 else 245 goto not_unique; 246 } 247 } 248 tw = NULL; 249 250 /* And established part... */ 251 sk_nulls_for_each(sk2, node, &head->chain) { 252 if (INET6_MATCH(sk2, net, hash, saddr, daddr, ports, dif)) 253 goto not_unique; 254 } 255 256 unique: 257 /* Must record num and sport now. Otherwise we will see 258 * in hash table socket with a funny identity. */ 259 inet->inet_num = lport; 260 inet->inet_sport = htons(lport); 261 sk->sk_hash = hash; 262 WARN_ON(!sk_unhashed(sk)); 263 __sk_nulls_add_node_rcu(sk, &head->chain); 264 if (tw) { 265 twrefcnt = inet_twsk_unhash(tw); 266 NET_INC_STATS_BH(net, LINUX_MIB_TIMEWAITRECYCLED); 267 } 268 spin_unlock(lock); 269 if (twrefcnt) 270 inet_twsk_put(tw); 271 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 272 273 if (twp) { 274 *twp = tw; 275 } else if (tw) { 276 /* Silly. Should hash-dance instead... */ 277 inet_twsk_deschedule(tw, death_row); 278 279 inet_twsk_put(tw); 280 } 281 return 0; 282 283 not_unique: 284 spin_unlock(lock); 285 return -EADDRNOTAVAIL; 286 } 287 288 static inline u32 inet6_sk_port_offset(const struct sock *sk) 289 { 290 const struct inet_sock *inet = inet_sk(sk); 291 const struct ipv6_pinfo *np = inet6_sk(sk); 292 return secure_ipv6_port_ephemeral(np->rcv_saddr.s6_addr32, 293 np->daddr.s6_addr32, 294 inet->inet_dport); 295 } 296 297 int inet6_hash_connect(struct inet_timewait_death_row *death_row, 298 struct sock *sk) 299 { 300 return __inet_hash_connect(death_row, sk, inet6_sk_port_offset(sk), 301 __inet6_check_established, __inet6_hash); 302 } 303 304 EXPORT_SYMBOL_GPL(inet6_hash_connect); 305