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 *daddr, 162 const unsigned short hnum, const int dif) 163 { 164 struct sock *sk; 165 const struct hlist_nulls_node *node; 166 struct sock *result; 167 int score, hiscore; 168 unsigned int hash = inet_lhashfn(net, hnum); 169 struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash]; 170 171 rcu_read_lock(); 172 begin: 173 result = NULL; 174 hiscore = -1; 175 sk_nulls_for_each(sk, node, &ilb->head) { 176 score = compute_score(sk, net, hnum, daddr, dif); 177 if (score > hiscore) { 178 hiscore = score; 179 result = sk; 180 } 181 } 182 /* 183 * if the nulls value we got at the end of this lookup is 184 * not the expected one, we must restart lookup. 185 * We probably met an item that was moved to another chain. 186 */ 187 if (get_nulls_value(node) != hash + LISTENING_NULLS_BASE) 188 goto begin; 189 if (result) { 190 if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt))) 191 result = NULL; 192 else if (unlikely(compute_score(result, net, hnum, daddr, 193 dif) < hiscore)) { 194 sock_put(result); 195 goto begin; 196 } 197 } 198 rcu_read_unlock(); 199 return result; 200 } 201 202 EXPORT_SYMBOL_GPL(inet6_lookup_listener); 203 204 struct sock *inet6_lookup(struct net *net, struct inet_hashinfo *hashinfo, 205 const struct in6_addr *saddr, const __be16 sport, 206 const struct in6_addr *daddr, const __be16 dport, 207 const int dif) 208 { 209 struct sock *sk; 210 211 local_bh_disable(); 212 sk = __inet6_lookup(net, hashinfo, saddr, sport, daddr, ntohs(dport), dif); 213 local_bh_enable(); 214 215 return sk; 216 } 217 218 EXPORT_SYMBOL_GPL(inet6_lookup); 219 220 static int __inet6_check_established(struct inet_timewait_death_row *death_row, 221 struct sock *sk, const __u16 lport, 222 struct inet_timewait_sock **twp) 223 { 224 struct inet_hashinfo *hinfo = death_row->hashinfo; 225 struct inet_sock *inet = inet_sk(sk); 226 const struct ipv6_pinfo *np = inet6_sk(sk); 227 const struct in6_addr *daddr = &np->rcv_saddr; 228 const struct in6_addr *saddr = &np->daddr; 229 const int dif = sk->sk_bound_dev_if; 230 const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport); 231 struct net *net = sock_net(sk); 232 const unsigned int hash = inet6_ehashfn(net, daddr, lport, saddr, 233 inet->inet_dport); 234 struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash); 235 spinlock_t *lock = inet_ehash_lockp(hinfo, hash); 236 struct sock *sk2; 237 const struct hlist_nulls_node *node; 238 struct inet_timewait_sock *tw; 239 int twrefcnt = 0; 240 241 spin_lock(lock); 242 243 /* Check TIME-WAIT sockets first. */ 244 sk_nulls_for_each(sk2, node, &head->twchain) { 245 if (sk2->sk_hash != hash) 246 continue; 247 248 if (likely(INET6_TW_MATCH(sk2, net, saddr, daddr, 249 ports, dif))) { 250 tw = inet_twsk(sk2); 251 if (twsk_unique(sk, sk2, twp)) 252 goto unique; 253 else 254 goto not_unique; 255 } 256 } 257 tw = NULL; 258 259 /* And established part... */ 260 sk_nulls_for_each(sk2, node, &head->chain) { 261 if (sk2->sk_hash != hash) 262 continue; 263 if (likely(INET6_MATCH(sk2, net, saddr, daddr, ports, dif))) 264 goto not_unique; 265 } 266 267 unique: 268 /* Must record num and sport now. Otherwise we will see 269 * in hash table socket with a funny identity. */ 270 inet->inet_num = lport; 271 inet->inet_sport = htons(lport); 272 sk->sk_hash = hash; 273 WARN_ON(!sk_unhashed(sk)); 274 __sk_nulls_add_node_rcu(sk, &head->chain); 275 if (tw) { 276 twrefcnt = inet_twsk_unhash(tw); 277 NET_INC_STATS_BH(net, LINUX_MIB_TIMEWAITRECYCLED); 278 } 279 spin_unlock(lock); 280 if (twrefcnt) 281 inet_twsk_put(tw); 282 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 283 284 if (twp) { 285 *twp = tw; 286 } else if (tw) { 287 /* Silly. Should hash-dance instead... */ 288 inet_twsk_deschedule(tw, death_row); 289 290 inet_twsk_put(tw); 291 } 292 return 0; 293 294 not_unique: 295 spin_unlock(lock); 296 return -EADDRNOTAVAIL; 297 } 298 299 static inline u32 inet6_sk_port_offset(const struct sock *sk) 300 { 301 const struct inet_sock *inet = inet_sk(sk); 302 const struct ipv6_pinfo *np = inet6_sk(sk); 303 return secure_ipv6_port_ephemeral(np->rcv_saddr.s6_addr32, 304 np->daddr.s6_addr32, 305 inet->inet_dport); 306 } 307 308 int inet6_hash_connect(struct inet_timewait_death_row *death_row, 309 struct sock *sk) 310 { 311 return __inet_hash_connect(death_row, sk, inet6_sk_port_offset(sk), 312 __inet6_check_established, __inet6_hash); 313 } 314 315 EXPORT_SYMBOL_GPL(inet6_hash_connect); 316