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