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/addrconf.h> 21 #include <net/inet_connection_sock.h> 22 #include <net/inet_hashtables.h> 23 #include <net/inet6_hashtables.h> 24 #include <net/secure_seq.h> 25 #include <net/ip.h> 26 #include <net/sock_reuseport.h> 27 28 u32 inet6_ehashfn(const struct net *net, 29 const struct in6_addr *laddr, const u16 lport, 30 const struct in6_addr *faddr, 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 /* 48 * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so 49 * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM 50 * 51 * The sockhash lock must be held as a reader here. 52 */ 53 struct sock *__inet6_lookup_established(struct net *net, 54 struct inet_hashinfo *hashinfo, 55 const struct in6_addr *saddr, 56 const __be16 sport, 57 const struct in6_addr *daddr, 58 const u16 hnum, 59 const int dif) 60 { 61 struct sock *sk; 62 const struct hlist_nulls_node *node; 63 const __portpair ports = INET_COMBINED_PORTS(sport, hnum); 64 /* Optimize here for direct hit, only listening connections can 65 * have wildcards anyways. 66 */ 67 unsigned int hash = inet6_ehashfn(net, daddr, hnum, saddr, sport); 68 unsigned int slot = hash & hashinfo->ehash_mask; 69 struct inet_ehash_bucket *head = &hashinfo->ehash[slot]; 70 71 72 rcu_read_lock(); 73 begin: 74 sk_nulls_for_each_rcu(sk, node, &head->chain) { 75 if (sk->sk_hash != hash) 76 continue; 77 if (!INET6_MATCH(sk, net, saddr, daddr, ports, dif)) 78 continue; 79 if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt))) 80 goto out; 81 82 if (unlikely(!INET6_MATCH(sk, net, saddr, daddr, ports, dif))) { 83 sock_gen_put(sk); 84 goto begin; 85 } 86 goto found; 87 } 88 if (get_nulls_value(node) != slot) 89 goto begin; 90 out: 91 sk = NULL; 92 found: 93 rcu_read_unlock(); 94 return sk; 95 } 96 EXPORT_SYMBOL(__inet6_lookup_established); 97 98 static inline int compute_score(struct sock *sk, struct net *net, 99 const unsigned short hnum, 100 const struct in6_addr *daddr, 101 const int dif) 102 { 103 int score = -1; 104 105 if (net_eq(sock_net(sk), net) && inet_sk(sk)->inet_num == hnum && 106 sk->sk_family == PF_INET6) { 107 108 score = 1; 109 if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr)) { 110 if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr)) 111 return -1; 112 score++; 113 } 114 if (sk->sk_bound_dev_if) { 115 if (sk->sk_bound_dev_if != dif) 116 return -1; 117 score++; 118 } 119 if (sk->sk_incoming_cpu == raw_smp_processor_id()) 120 score++; 121 } 122 return score; 123 } 124 125 struct sock *inet6_lookup_listener(struct net *net, 126 struct inet_hashinfo *hashinfo, 127 struct sk_buff *skb, int doff, 128 const struct in6_addr *saddr, 129 const __be16 sport, const struct in6_addr *daddr, 130 const unsigned short hnum, const int dif) 131 { 132 struct sock *sk; 133 const struct hlist_nulls_node *node; 134 struct sock *result; 135 int score, hiscore, matches = 0, reuseport = 0; 136 bool select_ok = true; 137 u32 phash = 0; 138 unsigned int hash = inet_lhashfn(net, hnum); 139 struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash]; 140 141 rcu_read_lock(); 142 begin: 143 result = NULL; 144 hiscore = 0; 145 sk_nulls_for_each(sk, node, &ilb->head) { 146 score = compute_score(sk, net, hnum, daddr, dif); 147 if (score > hiscore) { 148 hiscore = score; 149 result = sk; 150 reuseport = sk->sk_reuseport; 151 if (reuseport) { 152 phash = inet6_ehashfn(net, daddr, hnum, 153 saddr, sport); 154 if (select_ok) { 155 struct sock *sk2; 156 sk2 = reuseport_select_sock(sk, phash, 157 skb, doff); 158 if (sk2) { 159 result = sk2; 160 goto found; 161 } 162 } 163 matches = 1; 164 } 165 } else if (score == hiscore && reuseport) { 166 matches++; 167 if (reciprocal_scale(phash, matches) == 0) 168 result = sk; 169 phash = next_pseudo_random32(phash); 170 } 171 } 172 /* 173 * if the nulls value we got at the end of this lookup is 174 * not the expected one, we must restart lookup. 175 * We probably met an item that was moved to another chain. 176 */ 177 if (get_nulls_value(node) != hash + LISTENING_NULLS_BASE) 178 goto begin; 179 if (result) { 180 found: 181 if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt))) 182 result = NULL; 183 else if (unlikely(compute_score(result, net, hnum, daddr, 184 dif) < hiscore)) { 185 sock_put(result); 186 select_ok = false; 187 goto begin; 188 } 189 } 190 rcu_read_unlock(); 191 return result; 192 } 193 EXPORT_SYMBOL_GPL(inet6_lookup_listener); 194 195 struct sock *inet6_lookup(struct net *net, struct inet_hashinfo *hashinfo, 196 struct sk_buff *skb, int doff, 197 const struct in6_addr *saddr, const __be16 sport, 198 const struct in6_addr *daddr, const __be16 dport, 199 const int dif) 200 { 201 struct sock *sk; 202 203 local_bh_disable(); 204 sk = __inet6_lookup(net, hashinfo, skb, doff, saddr, sport, daddr, 205 ntohs(dport), dif); 206 local_bh_enable(); 207 208 return sk; 209 } 210 EXPORT_SYMBOL_GPL(inet6_lookup); 211 212 static int __inet6_check_established(struct inet_timewait_death_row *death_row, 213 struct sock *sk, const __u16 lport, 214 struct inet_timewait_sock **twp) 215 { 216 struct inet_hashinfo *hinfo = death_row->hashinfo; 217 struct inet_sock *inet = inet_sk(sk); 218 const struct in6_addr *daddr = &sk->sk_v6_rcv_saddr; 219 const struct in6_addr *saddr = &sk->sk_v6_daddr; 220 const int dif = sk->sk_bound_dev_if; 221 const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport); 222 struct net *net = sock_net(sk); 223 const unsigned int hash = inet6_ehashfn(net, daddr, lport, saddr, 224 inet->inet_dport); 225 struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash); 226 spinlock_t *lock = inet_ehash_lockp(hinfo, hash); 227 struct sock *sk2; 228 const struct hlist_nulls_node *node; 229 struct inet_timewait_sock *tw = NULL; 230 231 spin_lock(lock); 232 233 sk_nulls_for_each(sk2, node, &head->chain) { 234 if (sk2->sk_hash != hash) 235 continue; 236 237 if (likely(INET6_MATCH(sk2, net, saddr, daddr, ports, dif))) { 238 if (sk2->sk_state == TCP_TIME_WAIT) { 239 tw = inet_twsk(sk2); 240 if (twsk_unique(sk, sk2, twp)) 241 break; 242 } 243 goto not_unique; 244 } 245 } 246 247 /* Must record num and sport now. Otherwise we will see 248 * in hash table socket with a funny identity. 249 */ 250 inet->inet_num = lport; 251 inet->inet_sport = htons(lport); 252 sk->sk_hash = hash; 253 WARN_ON(!sk_unhashed(sk)); 254 __sk_nulls_add_node_rcu(sk, &head->chain); 255 if (tw) { 256 sk_nulls_del_node_init_rcu((struct sock *)tw); 257 NET_INC_STATS_BH(net, LINUX_MIB_TIMEWAITRECYCLED); 258 } 259 spin_unlock(lock); 260 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 261 262 if (twp) { 263 *twp = tw; 264 } else if (tw) { 265 /* Silly. Should hash-dance instead... */ 266 inet_twsk_deschedule_put(tw); 267 } 268 return 0; 269 270 not_unique: 271 spin_unlock(lock); 272 return -EADDRNOTAVAIL; 273 } 274 275 static u32 inet6_sk_port_offset(const struct sock *sk) 276 { 277 const struct inet_sock *inet = inet_sk(sk); 278 279 return secure_ipv6_port_ephemeral(sk->sk_v6_rcv_saddr.s6_addr32, 280 sk->sk_v6_daddr.s6_addr32, 281 inet->inet_dport); 282 } 283 284 int inet6_hash_connect(struct inet_timewait_death_row *death_row, 285 struct sock *sk) 286 { 287 u32 port_offset = 0; 288 289 if (!inet_sk(sk)->inet_num) 290 port_offset = inet6_sk_port_offset(sk); 291 return __inet_hash_connect(death_row, sk, port_offset, 292 __inet6_check_established); 293 } 294 EXPORT_SYMBOL_GPL(inet6_hash_connect); 295 296 int inet6_hash(struct sock *sk) 297 { 298 if (sk->sk_state != TCP_CLOSE) { 299 local_bh_disable(); 300 __inet_hash(sk, NULL, ipv6_rcv_saddr_equal); 301 local_bh_enable(); 302 } 303 304 return 0; 305 } 306 EXPORT_SYMBOL_GPL(inet6_hash); 307 308 /* match_wildcard == true: IPV6_ADDR_ANY equals to any IPv6 addresses if IPv6 309 * only, and any IPv4 addresses if not IPv6 only 310 * match_wildcard == false: addresses must be exactly the same, i.e. 311 * IPV6_ADDR_ANY only equals to IPV6_ADDR_ANY, 312 * and 0.0.0.0 equals to 0.0.0.0 only 313 */ 314 int ipv6_rcv_saddr_equal(const struct sock *sk, const struct sock *sk2, 315 bool match_wildcard) 316 { 317 const struct in6_addr *sk2_rcv_saddr6 = inet6_rcv_saddr(sk2); 318 int sk2_ipv6only = inet_v6_ipv6only(sk2); 319 int addr_type = ipv6_addr_type(&sk->sk_v6_rcv_saddr); 320 int addr_type2 = sk2_rcv_saddr6 ? ipv6_addr_type(sk2_rcv_saddr6) : IPV6_ADDR_MAPPED; 321 322 /* if both are mapped, treat as IPv4 */ 323 if (addr_type == IPV6_ADDR_MAPPED && addr_type2 == IPV6_ADDR_MAPPED) { 324 if (!sk2_ipv6only) { 325 if (sk->sk_rcv_saddr == sk2->sk_rcv_saddr) 326 return 1; 327 if (!sk->sk_rcv_saddr || !sk2->sk_rcv_saddr) 328 return match_wildcard; 329 } 330 return 0; 331 } 332 333 if (addr_type == IPV6_ADDR_ANY && addr_type2 == IPV6_ADDR_ANY) 334 return 1; 335 336 if (addr_type2 == IPV6_ADDR_ANY && match_wildcard && 337 !(sk2_ipv6only && addr_type == IPV6_ADDR_MAPPED)) 338 return 1; 339 340 if (addr_type == IPV6_ADDR_ANY && match_wildcard && 341 !(ipv6_only_sock(sk) && addr_type2 == IPV6_ADDR_MAPPED)) 342 return 1; 343 344 if (sk2_rcv_saddr6 && 345 ipv6_addr_equal(&sk->sk_v6_rcv_saddr, sk2_rcv_saddr6)) 346 return 1; 347 348 return 0; 349 } 350 EXPORT_SYMBOL_GPL(ipv6_rcv_saddr_equal); 351