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 static unsigned int inet6_ehashfn(struct net *net, 27 const struct in6_addr *laddr, 28 const u16 lport, 29 const struct in6_addr *faddr, 30 const __be16 fport) 31 { 32 static u32 inet6_ehash_secret __read_mostly; 33 static u32 ipv6_hash_secret __read_mostly; 34 35 u32 lhash, fhash; 36 37 net_get_random_once(&inet6_ehash_secret, sizeof(inet6_ehash_secret)); 38 net_get_random_once(&ipv6_hash_secret, sizeof(ipv6_hash_secret)); 39 40 lhash = (__force u32)laddr->s6_addr32[3]; 41 fhash = __ipv6_addr_jhash(faddr, ipv6_hash_secret); 42 43 return __inet6_ehashfn(lhash, lport, fhash, fport, 44 inet6_ehash_secret + net_hash_mix(net)); 45 } 46 47 static int inet6_sk_ehashfn(const struct sock *sk) 48 { 49 const struct inet_sock *inet = inet_sk(sk); 50 const struct in6_addr *laddr = &sk->sk_v6_rcv_saddr; 51 const struct in6_addr *faddr = &sk->sk_v6_daddr; 52 const __u16 lport = inet->inet_num; 53 const __be16 fport = inet->inet_dport; 54 struct net *net = sock_net(sk); 55 56 return inet6_ehashfn(net, laddr, lport, faddr, fport); 57 } 58 59 int __inet6_hash(struct sock *sk, struct inet_timewait_sock *tw) 60 { 61 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo; 62 int twrefcnt = 0; 63 64 WARN_ON(!sk_unhashed(sk)); 65 66 if (sk->sk_state == TCP_LISTEN) { 67 struct inet_listen_hashbucket *ilb; 68 69 ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)]; 70 spin_lock(&ilb->lock); 71 __sk_nulls_add_node_rcu(sk, &ilb->head); 72 spin_unlock(&ilb->lock); 73 } else { 74 unsigned int hash; 75 struct hlist_nulls_head *list; 76 spinlock_t *lock; 77 78 sk->sk_hash = hash = inet6_sk_ehashfn(sk); 79 list = &inet_ehash_bucket(hashinfo, hash)->chain; 80 lock = inet_ehash_lockp(hashinfo, hash); 81 spin_lock(lock); 82 __sk_nulls_add_node_rcu(sk, list); 83 if (tw) { 84 WARN_ON(sk->sk_hash != tw->tw_hash); 85 twrefcnt = inet_twsk_unhash(tw); 86 } 87 spin_unlock(lock); 88 } 89 90 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 91 return twrefcnt; 92 } 93 EXPORT_SYMBOL(__inet6_hash); 94 95 /* 96 * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so 97 * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM 98 * 99 * The sockhash lock must be held as a reader here. 100 */ 101 struct sock *__inet6_lookup_established(struct net *net, 102 struct inet_hashinfo *hashinfo, 103 const struct in6_addr *saddr, 104 const __be16 sport, 105 const struct in6_addr *daddr, 106 const u16 hnum, 107 const int dif) 108 { 109 struct sock *sk; 110 const struct hlist_nulls_node *node; 111 const __portpair ports = INET_COMBINED_PORTS(sport, hnum); 112 /* Optimize here for direct hit, only listening connections can 113 * have wildcards anyways. 114 */ 115 unsigned int hash = inet6_ehashfn(net, daddr, hnum, saddr, sport); 116 unsigned int slot = hash & hashinfo->ehash_mask; 117 struct inet_ehash_bucket *head = &hashinfo->ehash[slot]; 118 119 120 rcu_read_lock(); 121 begin: 122 sk_nulls_for_each_rcu(sk, node, &head->chain) { 123 if (sk->sk_hash != hash) 124 continue; 125 if (!INET6_MATCH(sk, net, saddr, daddr, ports, dif)) 126 continue; 127 if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt))) 128 goto out; 129 130 if (unlikely(!INET6_MATCH(sk, net, saddr, daddr, ports, dif))) { 131 sock_gen_put(sk); 132 goto begin; 133 } 134 goto found; 135 } 136 if (get_nulls_value(node) != slot) 137 goto begin; 138 out: 139 sk = NULL; 140 found: 141 rcu_read_unlock(); 142 return sk; 143 } 144 EXPORT_SYMBOL(__inet6_lookup_established); 145 146 static inline int compute_score(struct sock *sk, struct net *net, 147 const unsigned short hnum, 148 const struct in6_addr *daddr, 149 const int dif) 150 { 151 int score = -1; 152 153 if (net_eq(sock_net(sk), net) && inet_sk(sk)->inet_num == hnum && 154 sk->sk_family == PF_INET6) { 155 156 score = 1; 157 if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr)) { 158 if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr)) 159 return -1; 160 score++; 161 } 162 if (sk->sk_bound_dev_if) { 163 if (sk->sk_bound_dev_if != dif) 164 return -1; 165 score++; 166 } 167 } 168 return score; 169 } 170 171 struct sock *inet6_lookup_listener(struct net *net, 172 struct inet_hashinfo *hashinfo, const struct in6_addr *saddr, 173 const __be16 sport, const struct in6_addr *daddr, 174 const unsigned short hnum, const int dif) 175 { 176 struct sock *sk; 177 const struct hlist_nulls_node *node; 178 struct sock *result; 179 int score, hiscore, matches = 0, reuseport = 0; 180 u32 phash = 0; 181 unsigned int hash = inet_lhashfn(net, hnum); 182 struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash]; 183 184 rcu_read_lock(); 185 begin: 186 result = NULL; 187 hiscore = 0; 188 sk_nulls_for_each(sk, node, &ilb->head) { 189 score = compute_score(sk, net, hnum, daddr, dif); 190 if (score > hiscore) { 191 hiscore = score; 192 result = sk; 193 reuseport = sk->sk_reuseport; 194 if (reuseport) { 195 phash = inet6_ehashfn(net, daddr, hnum, 196 saddr, sport); 197 matches = 1; 198 } 199 } else if (score == hiscore && reuseport) { 200 matches++; 201 if (((u64)phash * matches) >> 32 == 0) 202 result = sk; 203 phash = next_pseudo_random32(phash); 204 } 205 } 206 /* 207 * if the nulls value we got at the end of this lookup is 208 * not the expected one, we must restart lookup. 209 * We probably met an item that was moved to another chain. 210 */ 211 if (get_nulls_value(node) != hash + LISTENING_NULLS_BASE) 212 goto begin; 213 if (result) { 214 if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt))) 215 result = NULL; 216 else if (unlikely(compute_score(result, net, hnum, daddr, 217 dif) < hiscore)) { 218 sock_put(result); 219 goto begin; 220 } 221 } 222 rcu_read_unlock(); 223 return result; 224 } 225 226 EXPORT_SYMBOL_GPL(inet6_lookup_listener); 227 228 struct sock *inet6_lookup(struct net *net, struct inet_hashinfo *hashinfo, 229 const struct in6_addr *saddr, const __be16 sport, 230 const struct in6_addr *daddr, const __be16 dport, 231 const int dif) 232 { 233 struct sock *sk; 234 235 local_bh_disable(); 236 sk = __inet6_lookup(net, hashinfo, saddr, sport, daddr, ntohs(dport), dif); 237 local_bh_enable(); 238 239 return sk; 240 } 241 242 EXPORT_SYMBOL_GPL(inet6_lookup); 243 244 static int __inet6_check_established(struct inet_timewait_death_row *death_row, 245 struct sock *sk, const __u16 lport, 246 struct inet_timewait_sock **twp) 247 { 248 struct inet_hashinfo *hinfo = death_row->hashinfo; 249 struct inet_sock *inet = inet_sk(sk); 250 const struct in6_addr *daddr = &sk->sk_v6_rcv_saddr; 251 const struct in6_addr *saddr = &sk->sk_v6_daddr; 252 const int dif = sk->sk_bound_dev_if; 253 const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport); 254 struct net *net = sock_net(sk); 255 const unsigned int hash = inet6_ehashfn(net, daddr, lport, saddr, 256 inet->inet_dport); 257 struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash); 258 spinlock_t *lock = inet_ehash_lockp(hinfo, hash); 259 struct sock *sk2; 260 const struct hlist_nulls_node *node; 261 struct inet_timewait_sock *tw = NULL; 262 int twrefcnt = 0; 263 264 spin_lock(lock); 265 266 sk_nulls_for_each(sk2, node, &head->chain) { 267 if (sk2->sk_hash != hash) 268 continue; 269 270 if (likely(INET6_MATCH(sk2, net, saddr, daddr, ports, dif))) { 271 if (sk2->sk_state == TCP_TIME_WAIT) { 272 tw = inet_twsk(sk2); 273 if (twsk_unique(sk, sk2, twp)) 274 break; 275 } 276 goto not_unique; 277 } 278 } 279 280 /* Must record num and sport now. Otherwise we will see 281 * in hash table socket with a funny identity. 282 */ 283 inet->inet_num = lport; 284 inet->inet_sport = htons(lport); 285 sk->sk_hash = hash; 286 WARN_ON(!sk_unhashed(sk)); 287 __sk_nulls_add_node_rcu(sk, &head->chain); 288 if (tw) { 289 twrefcnt = inet_twsk_unhash(tw); 290 NET_INC_STATS_BH(net, LINUX_MIB_TIMEWAITRECYCLED); 291 } 292 spin_unlock(lock); 293 if (twrefcnt) 294 inet_twsk_put(tw); 295 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 296 297 if (twp) { 298 *twp = tw; 299 } else if (tw) { 300 /* Silly. Should hash-dance instead... */ 301 inet_twsk_deschedule(tw, death_row); 302 303 inet_twsk_put(tw); 304 } 305 return 0; 306 307 not_unique: 308 spin_unlock(lock); 309 return -EADDRNOTAVAIL; 310 } 311 312 static inline u32 inet6_sk_port_offset(const struct sock *sk) 313 { 314 const struct inet_sock *inet = inet_sk(sk); 315 316 return secure_ipv6_port_ephemeral(sk->sk_v6_rcv_saddr.s6_addr32, 317 sk->sk_v6_daddr.s6_addr32, 318 inet->inet_dport); 319 } 320 321 int inet6_hash_connect(struct inet_timewait_death_row *death_row, 322 struct sock *sk) 323 { 324 return __inet_hash_connect(death_row, sk, inet6_sk_port_offset(sk), 325 __inet6_check_established, __inet6_hash); 326 } 327 328 EXPORT_SYMBOL_GPL(inet6_hash_connect); 329