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 if (sk->sk_incoming_cpu == raw_smp_processor_id()) 118 score++; 119 } 120 return score; 121 } 122 123 struct sock *inet6_lookup_listener(struct net *net, 124 struct inet_hashinfo *hashinfo, const struct in6_addr *saddr, 125 const __be16 sport, const struct in6_addr *daddr, 126 const unsigned short hnum, const int dif) 127 { 128 struct sock *sk; 129 const struct hlist_nulls_node *node; 130 struct sock *result; 131 int score, hiscore, matches = 0, reuseport = 0; 132 u32 phash = 0; 133 unsigned int hash = inet_lhashfn(net, hnum); 134 struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash]; 135 136 rcu_read_lock(); 137 begin: 138 result = NULL; 139 hiscore = 0; 140 sk_nulls_for_each(sk, node, &ilb->head) { 141 score = compute_score(sk, net, hnum, daddr, dif); 142 if (score > hiscore) { 143 hiscore = score; 144 result = sk; 145 reuseport = sk->sk_reuseport; 146 if (reuseport) { 147 phash = inet6_ehashfn(net, daddr, hnum, 148 saddr, sport); 149 matches = 1; 150 } 151 } else if (score == hiscore && reuseport) { 152 matches++; 153 if (reciprocal_scale(phash, matches) == 0) 154 result = sk; 155 phash = next_pseudo_random32(phash); 156 } 157 } 158 /* 159 * if the nulls value we got at the end of this lookup is 160 * not the expected one, we must restart lookup. 161 * We probably met an item that was moved to another chain. 162 */ 163 if (get_nulls_value(node) != hash + LISTENING_NULLS_BASE) 164 goto begin; 165 if (result) { 166 if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt))) 167 result = NULL; 168 else if (unlikely(compute_score(result, net, hnum, daddr, 169 dif) < hiscore)) { 170 sock_put(result); 171 goto begin; 172 } 173 } 174 rcu_read_unlock(); 175 return result; 176 } 177 EXPORT_SYMBOL_GPL(inet6_lookup_listener); 178 179 struct sock *inet6_lookup(struct net *net, struct inet_hashinfo *hashinfo, 180 const struct in6_addr *saddr, const __be16 sport, 181 const struct in6_addr *daddr, const __be16 dport, 182 const int dif) 183 { 184 struct sock *sk; 185 186 local_bh_disable(); 187 sk = __inet6_lookup(net, hashinfo, saddr, sport, daddr, ntohs(dport), dif); 188 local_bh_enable(); 189 190 return sk; 191 } 192 EXPORT_SYMBOL_GPL(inet6_lookup); 193 194 static int __inet6_check_established(struct inet_timewait_death_row *death_row, 195 struct sock *sk, const __u16 lport, 196 struct inet_timewait_sock **twp) 197 { 198 struct inet_hashinfo *hinfo = death_row->hashinfo; 199 struct inet_sock *inet = inet_sk(sk); 200 const struct in6_addr *daddr = &sk->sk_v6_rcv_saddr; 201 const struct in6_addr *saddr = &sk->sk_v6_daddr; 202 const int dif = sk->sk_bound_dev_if; 203 const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport); 204 struct net *net = sock_net(sk); 205 const unsigned int hash = inet6_ehashfn(net, daddr, lport, saddr, 206 inet->inet_dport); 207 struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash); 208 spinlock_t *lock = inet_ehash_lockp(hinfo, hash); 209 struct sock *sk2; 210 const struct hlist_nulls_node *node; 211 struct inet_timewait_sock *tw = NULL; 212 213 spin_lock(lock); 214 215 sk_nulls_for_each(sk2, node, &head->chain) { 216 if (sk2->sk_hash != hash) 217 continue; 218 219 if (likely(INET6_MATCH(sk2, net, saddr, daddr, ports, dif))) { 220 if (sk2->sk_state == TCP_TIME_WAIT) { 221 tw = inet_twsk(sk2); 222 if (twsk_unique(sk, sk2, twp)) 223 break; 224 } 225 goto not_unique; 226 } 227 } 228 229 /* Must record num and sport now. Otherwise we will see 230 * in hash table socket with a funny identity. 231 */ 232 inet->inet_num = lport; 233 inet->inet_sport = htons(lport); 234 sk->sk_hash = hash; 235 WARN_ON(!sk_unhashed(sk)); 236 __sk_nulls_add_node_rcu(sk, &head->chain); 237 if (tw) { 238 sk_nulls_del_node_init_rcu((struct sock *)tw); 239 NET_INC_STATS_BH(net, LINUX_MIB_TIMEWAITRECYCLED); 240 } 241 spin_unlock(lock); 242 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 243 244 if (twp) { 245 *twp = tw; 246 } else if (tw) { 247 /* Silly. Should hash-dance instead... */ 248 inet_twsk_deschedule_put(tw); 249 } 250 return 0; 251 252 not_unique: 253 spin_unlock(lock); 254 return -EADDRNOTAVAIL; 255 } 256 257 static u32 inet6_sk_port_offset(const struct sock *sk) 258 { 259 const struct inet_sock *inet = inet_sk(sk); 260 261 return secure_ipv6_port_ephemeral(sk->sk_v6_rcv_saddr.s6_addr32, 262 sk->sk_v6_daddr.s6_addr32, 263 inet->inet_dport); 264 } 265 266 int inet6_hash_connect(struct inet_timewait_death_row *death_row, 267 struct sock *sk) 268 { 269 u32 port_offset = 0; 270 271 if (!inet_sk(sk)->inet_num) 272 port_offset = inet6_sk_port_offset(sk); 273 return __inet_hash_connect(death_row, sk, port_offset, 274 __inet6_check_established); 275 } 276 EXPORT_SYMBOL_GPL(inet6_hash_connect); 277