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, const int sdif) 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 begin: 73 sk_nulls_for_each_rcu(sk, node, &head->chain) { 74 if (sk->sk_hash != hash) 75 continue; 76 if (!INET6_MATCH(sk, net, saddr, daddr, ports, dif, sdif)) 77 continue; 78 if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt))) 79 goto out; 80 81 if (unlikely(!INET6_MATCH(sk, net, saddr, daddr, ports, dif, sdif))) { 82 sock_gen_put(sk); 83 goto begin; 84 } 85 goto found; 86 } 87 if (get_nulls_value(node) != slot) 88 goto begin; 89 out: 90 sk = NULL; 91 found: 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, const int sdif, bool exact_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 || exact_dif) { 113 bool dev_match = (sk->sk_bound_dev_if == dif || 114 sk->sk_bound_dev_if == sdif); 115 116 if (!dev_match) 117 return -1; 118 if (sk->sk_bound_dev_if) 119 score++; 120 } 121 if (sk->sk_incoming_cpu == raw_smp_processor_id()) 122 score++; 123 } 124 return score; 125 } 126 127 /* called with rcu_read_lock() */ 128 static struct sock *inet6_lhash2_lookup(struct net *net, 129 struct inet_listen_hashbucket *ilb2, 130 struct sk_buff *skb, int doff, 131 const struct in6_addr *saddr, 132 const __be16 sport, const struct in6_addr *daddr, 133 const unsigned short hnum, const int dif, const int sdif) 134 { 135 bool exact_dif = inet6_exact_dif_match(net, skb); 136 struct inet_connection_sock *icsk; 137 struct sock *sk, *result = NULL; 138 int score, hiscore = 0; 139 u32 phash = 0; 140 141 inet_lhash2_for_each_icsk_rcu(icsk, &ilb2->head) { 142 sk = (struct sock *)icsk; 143 score = compute_score(sk, net, hnum, daddr, dif, sdif, 144 exact_dif); 145 if (score > hiscore) { 146 if (sk->sk_reuseport) { 147 phash = inet6_ehashfn(net, daddr, hnum, 148 saddr, sport); 149 result = reuseport_select_sock(sk, phash, 150 skb, doff); 151 if (result) 152 return result; 153 } 154 result = sk; 155 hiscore = score; 156 } 157 } 158 159 return result; 160 } 161 162 struct sock *inet6_lookup_listener(struct net *net, 163 struct inet_hashinfo *hashinfo, 164 struct sk_buff *skb, int doff, 165 const struct in6_addr *saddr, 166 const __be16 sport, const struct in6_addr *daddr, 167 const unsigned short hnum, const int dif, const int sdif) 168 { 169 unsigned int hash = inet_lhashfn(net, hnum); 170 struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash]; 171 bool exact_dif = inet6_exact_dif_match(net, skb); 172 struct inet_listen_hashbucket *ilb2; 173 struct sock *sk, *result = NULL; 174 int score, hiscore = 0; 175 unsigned int hash2; 176 u32 phash = 0; 177 178 if (ilb->count <= 10 || !hashinfo->lhash2) 179 goto port_lookup; 180 181 /* Too many sk in the ilb bucket (which is hashed by port alone). 182 * Try lhash2 (which is hashed by port and addr) instead. 183 */ 184 185 hash2 = ipv6_portaddr_hash(net, daddr, hnum); 186 ilb2 = inet_lhash2_bucket(hashinfo, hash2); 187 if (ilb2->count > ilb->count) 188 goto port_lookup; 189 190 result = inet6_lhash2_lookup(net, ilb2, skb, doff, 191 saddr, sport, daddr, hnum, 192 dif, sdif); 193 if (result) 194 goto done; 195 196 /* Lookup lhash2 with in6addr_any */ 197 198 hash2 = ipv6_portaddr_hash(net, &in6addr_any, hnum); 199 ilb2 = inet_lhash2_bucket(hashinfo, hash2); 200 if (ilb2->count > ilb->count) 201 goto port_lookup; 202 203 result = inet6_lhash2_lookup(net, ilb2, skb, doff, 204 saddr, sport, daddr, hnum, 205 dif, sdif); 206 goto done; 207 208 port_lookup: 209 sk_for_each(sk, &ilb->head) { 210 score = compute_score(sk, net, hnum, daddr, dif, sdif, exact_dif); 211 if (score > hiscore) { 212 if (sk->sk_reuseport) { 213 phash = inet6_ehashfn(net, daddr, hnum, 214 saddr, sport); 215 result = reuseport_select_sock(sk, phash, 216 skb, doff); 217 if (result) 218 goto done; 219 } 220 result = sk; 221 hiscore = score; 222 } 223 } 224 done: 225 if (unlikely(IS_ERR(result))) 226 return NULL; 227 return result; 228 } 229 EXPORT_SYMBOL_GPL(inet6_lookup_listener); 230 231 struct sock *inet6_lookup(struct net *net, struct inet_hashinfo *hashinfo, 232 struct sk_buff *skb, int doff, 233 const struct in6_addr *saddr, const __be16 sport, 234 const struct in6_addr *daddr, const __be16 dport, 235 const int dif) 236 { 237 struct sock *sk; 238 bool refcounted; 239 240 sk = __inet6_lookup(net, hashinfo, skb, doff, saddr, sport, daddr, 241 ntohs(dport), dif, 0, &refcounted); 242 if (sk && !refcounted && !refcount_inc_not_zero(&sk->sk_refcnt)) 243 sk = NULL; 244 return sk; 245 } 246 EXPORT_SYMBOL_GPL(inet6_lookup); 247 248 static int __inet6_check_established(struct inet_timewait_death_row *death_row, 249 struct sock *sk, const __u16 lport, 250 struct inet_timewait_sock **twp) 251 { 252 struct inet_hashinfo *hinfo = death_row->hashinfo; 253 struct inet_sock *inet = inet_sk(sk); 254 const struct in6_addr *daddr = &sk->sk_v6_rcv_saddr; 255 const struct in6_addr *saddr = &sk->sk_v6_daddr; 256 const int dif = sk->sk_bound_dev_if; 257 struct net *net = sock_net(sk); 258 const int sdif = l3mdev_master_ifindex_by_index(net, dif); 259 const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport); 260 const unsigned int hash = inet6_ehashfn(net, daddr, lport, saddr, 261 inet->inet_dport); 262 struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash); 263 spinlock_t *lock = inet_ehash_lockp(hinfo, hash); 264 struct sock *sk2; 265 const struct hlist_nulls_node *node; 266 struct inet_timewait_sock *tw = NULL; 267 268 spin_lock(lock); 269 270 sk_nulls_for_each(sk2, node, &head->chain) { 271 if (sk2->sk_hash != hash) 272 continue; 273 274 if (likely(INET6_MATCH(sk2, net, saddr, daddr, ports, 275 dif, sdif))) { 276 if (sk2->sk_state == TCP_TIME_WAIT) { 277 tw = inet_twsk(sk2); 278 if (twsk_unique(sk, sk2, twp)) 279 break; 280 } 281 goto not_unique; 282 } 283 } 284 285 /* Must record num and sport now. Otherwise we will see 286 * in hash table socket with a funny identity. 287 */ 288 inet->inet_num = lport; 289 inet->inet_sport = htons(lport); 290 sk->sk_hash = hash; 291 WARN_ON(!sk_unhashed(sk)); 292 __sk_nulls_add_node_rcu(sk, &head->chain); 293 if (tw) { 294 sk_nulls_del_node_init_rcu((struct sock *)tw); 295 __NET_INC_STATS(net, LINUX_MIB_TIMEWAITRECYCLED); 296 } 297 spin_unlock(lock); 298 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 299 300 if (twp) { 301 *twp = tw; 302 } else if (tw) { 303 /* Silly. Should hash-dance instead... */ 304 inet_twsk_deschedule_put(tw); 305 } 306 return 0; 307 308 not_unique: 309 spin_unlock(lock); 310 return -EADDRNOTAVAIL; 311 } 312 313 static u32 inet6_sk_port_offset(const struct sock *sk) 314 { 315 const struct inet_sock *inet = inet_sk(sk); 316 317 return secure_ipv6_port_ephemeral(sk->sk_v6_rcv_saddr.s6_addr32, 318 sk->sk_v6_daddr.s6_addr32, 319 inet->inet_dport); 320 } 321 322 int inet6_hash_connect(struct inet_timewait_death_row *death_row, 323 struct sock *sk) 324 { 325 u32 port_offset = 0; 326 327 if (!inet_sk(sk)->inet_num) 328 port_offset = inet6_sk_port_offset(sk); 329 return __inet_hash_connect(death_row, sk, port_offset, 330 __inet6_check_established); 331 } 332 EXPORT_SYMBOL_GPL(inet6_hash_connect); 333 334 int inet6_hash(struct sock *sk) 335 { 336 int err = 0; 337 338 if (sk->sk_state != TCP_CLOSE) { 339 local_bh_disable(); 340 err = __inet_hash(sk, NULL); 341 local_bh_enable(); 342 } 343 344 return err; 345 } 346 EXPORT_SYMBOL_GPL(inet6_hash); 347