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/ip.h> 24 25 void __inet6_hash(struct inet_hashinfo *hashinfo, 26 struct sock *sk) 27 { 28 struct hlist_head *list; 29 rwlock_t *lock; 30 31 BUG_TRAP(sk_unhashed(sk)); 32 33 if (sk->sk_state == TCP_LISTEN) { 34 list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)]; 35 lock = &hashinfo->lhash_lock; 36 inet_listen_wlock(hashinfo); 37 } else { 38 unsigned int hash; 39 sk->sk_hash = hash = inet6_sk_ehashfn(sk); 40 list = &inet_ehash_bucket(hashinfo, hash)->chain; 41 lock = inet_ehash_lockp(hashinfo, hash); 42 write_lock(lock); 43 } 44 45 __sk_add_node(sk, list); 46 sock_prot_inc_use(sk->sk_prot); 47 write_unlock(lock); 48 } 49 EXPORT_SYMBOL(__inet6_hash); 50 51 /* 52 * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so 53 * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM 54 * 55 * The sockhash lock must be held as a reader here. 56 */ 57 struct sock *__inet6_lookup_established(struct inet_hashinfo *hashinfo, 58 const struct in6_addr *saddr, 59 const __be16 sport, 60 const struct in6_addr *daddr, 61 const u16 hnum, 62 const int dif) 63 { 64 struct sock *sk; 65 const struct hlist_node *node; 66 const __portpair ports = INET_COMBINED_PORTS(sport, hnum); 67 /* Optimize here for direct hit, only listening connections can 68 * have wildcards anyways. 69 */ 70 unsigned int hash = inet6_ehashfn(daddr, hnum, saddr, sport); 71 struct inet_ehash_bucket *head = inet_ehash_bucket(hashinfo, hash); 72 rwlock_t *lock = inet_ehash_lockp(hashinfo, hash); 73 74 prefetch(head->chain.first); 75 read_lock(lock); 76 sk_for_each(sk, node, &head->chain) { 77 /* For IPV6 do the cheaper port and family tests first. */ 78 if (INET6_MATCH(sk, hash, saddr, daddr, ports, dif)) 79 goto hit; /* You sunk my battleship! */ 80 } 81 /* Must check for a TIME_WAIT'er before going to listener hash. */ 82 sk_for_each(sk, node, &head->twchain) { 83 const struct inet_timewait_sock *tw = inet_twsk(sk); 84 85 if(*((__portpair *)&(tw->tw_dport)) == ports && 86 sk->sk_family == PF_INET6) { 87 const struct inet6_timewait_sock *tw6 = inet6_twsk(sk); 88 89 if (ipv6_addr_equal(&tw6->tw_v6_daddr, saddr) && 90 ipv6_addr_equal(&tw6->tw_v6_rcv_saddr, daddr) && 91 (!sk->sk_bound_dev_if || sk->sk_bound_dev_if == dif)) 92 goto hit; 93 } 94 } 95 read_unlock(lock); 96 return NULL; 97 98 hit: 99 sock_hold(sk); 100 read_unlock(lock); 101 return sk; 102 } 103 EXPORT_SYMBOL(__inet6_lookup_established); 104 105 struct sock *inet6_lookup_listener(struct inet_hashinfo *hashinfo, 106 const struct in6_addr *daddr, 107 const unsigned short hnum, const int dif) 108 { 109 struct sock *sk; 110 const struct hlist_node *node; 111 struct sock *result = NULL; 112 int score, hiscore = 0; 113 114 read_lock(&hashinfo->lhash_lock); 115 sk_for_each(sk, node, &hashinfo->listening_hash[inet_lhashfn(hnum)]) { 116 if (inet_sk(sk)->num == hnum && sk->sk_family == PF_INET6) { 117 const struct ipv6_pinfo *np = inet6_sk(sk); 118 119 score = 1; 120 if (!ipv6_addr_any(&np->rcv_saddr)) { 121 if (!ipv6_addr_equal(&np->rcv_saddr, daddr)) 122 continue; 123 score++; 124 } 125 if (sk->sk_bound_dev_if) { 126 if (sk->sk_bound_dev_if != dif) 127 continue; 128 score++; 129 } 130 if (score == 3) { 131 result = sk; 132 break; 133 } 134 if (score > hiscore) { 135 hiscore = score; 136 result = sk; 137 } 138 } 139 } 140 if (result) 141 sock_hold(result); 142 read_unlock(&hashinfo->lhash_lock); 143 return result; 144 } 145 146 EXPORT_SYMBOL_GPL(inet6_lookup_listener); 147 148 struct sock *inet6_lookup(struct inet_hashinfo *hashinfo, 149 const struct in6_addr *saddr, const __be16 sport, 150 const struct in6_addr *daddr, const __be16 dport, 151 const int dif) 152 { 153 struct sock *sk; 154 155 local_bh_disable(); 156 sk = __inet6_lookup(hashinfo, saddr, sport, daddr, ntohs(dport), dif); 157 local_bh_enable(); 158 159 return sk; 160 } 161 162 EXPORT_SYMBOL_GPL(inet6_lookup); 163 164 static int __inet6_check_established(struct inet_timewait_death_row *death_row, 165 struct sock *sk, const __u16 lport, 166 struct inet_timewait_sock **twp) 167 { 168 struct inet_hashinfo *hinfo = death_row->hashinfo; 169 struct inet_sock *inet = inet_sk(sk); 170 const struct ipv6_pinfo *np = inet6_sk(sk); 171 const struct in6_addr *daddr = &np->rcv_saddr; 172 const struct in6_addr *saddr = &np->daddr; 173 const int dif = sk->sk_bound_dev_if; 174 const __portpair ports = INET_COMBINED_PORTS(inet->dport, lport); 175 const unsigned int hash = inet6_ehashfn(daddr, lport, saddr, 176 inet->dport); 177 struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash); 178 rwlock_t *lock = inet_ehash_lockp(hinfo, hash); 179 struct sock *sk2; 180 const struct hlist_node *node; 181 struct inet_timewait_sock *tw; 182 183 prefetch(head->chain.first); 184 write_lock(lock); 185 186 /* Check TIME-WAIT sockets first. */ 187 sk_for_each(sk2, node, &head->twchain) { 188 const struct inet6_timewait_sock *tw6 = inet6_twsk(sk2); 189 190 tw = inet_twsk(sk2); 191 192 if(*((__portpair *)&(tw->tw_dport)) == ports && 193 sk2->sk_family == PF_INET6 && 194 ipv6_addr_equal(&tw6->tw_v6_daddr, saddr) && 195 ipv6_addr_equal(&tw6->tw_v6_rcv_saddr, daddr) && 196 (!sk2->sk_bound_dev_if || sk2->sk_bound_dev_if == dif)) { 197 if (twsk_unique(sk, sk2, twp)) 198 goto unique; 199 else 200 goto not_unique; 201 } 202 } 203 tw = NULL; 204 205 /* And established part... */ 206 sk_for_each(sk2, node, &head->chain) { 207 if (INET6_MATCH(sk2, hash, saddr, daddr, ports, dif)) 208 goto not_unique; 209 } 210 211 unique: 212 /* Must record num and sport now. Otherwise we will see 213 * in hash table socket with a funny identity. */ 214 inet->num = lport; 215 inet->sport = htons(lport); 216 BUG_TRAP(sk_unhashed(sk)); 217 __sk_add_node(sk, &head->chain); 218 sk->sk_hash = hash; 219 sock_prot_inc_use(sk->sk_prot); 220 write_unlock(lock); 221 222 if (twp != NULL) { 223 *twp = tw; 224 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED); 225 } else if (tw != NULL) { 226 /* Silly. Should hash-dance instead... */ 227 inet_twsk_deschedule(tw, death_row); 228 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED); 229 230 inet_twsk_put(tw); 231 } 232 return 0; 233 234 not_unique: 235 write_unlock(lock); 236 return -EADDRNOTAVAIL; 237 } 238 239 static inline u32 inet6_sk_port_offset(const struct sock *sk) 240 { 241 const struct inet_sock *inet = inet_sk(sk); 242 const struct ipv6_pinfo *np = inet6_sk(sk); 243 return secure_ipv6_port_ephemeral(np->rcv_saddr.s6_addr32, 244 np->daddr.s6_addr32, 245 inet->dport); 246 } 247 248 int inet6_hash_connect(struct inet_timewait_death_row *death_row, 249 struct sock *sk) 250 { 251 struct inet_hashinfo *hinfo = death_row->hashinfo; 252 const unsigned short snum = inet_sk(sk)->num; 253 struct inet_bind_hashbucket *head; 254 struct inet_bind_bucket *tb; 255 int ret; 256 257 if (snum == 0) { 258 int i, port, low, high, remaining; 259 static u32 hint; 260 const u32 offset = hint + inet6_sk_port_offset(sk); 261 struct hlist_node *node; 262 struct inet_timewait_sock *tw = NULL; 263 264 inet_get_local_port_range(&low, &high); 265 remaining = (high - low) + 1; 266 267 local_bh_disable(); 268 for (i = 1; i <= remaining; i++) { 269 port = low + (i + offset) % remaining; 270 head = &hinfo->bhash[inet_bhashfn(port, hinfo->bhash_size)]; 271 spin_lock(&head->lock); 272 273 /* Does not bother with rcv_saddr checks, 274 * because the established check is already 275 * unique enough. 276 */ 277 inet_bind_bucket_for_each(tb, node, &head->chain) { 278 if (tb->port == port) { 279 BUG_TRAP(!hlist_empty(&tb->owners)); 280 if (tb->fastreuse >= 0) 281 goto next_port; 282 if (!__inet6_check_established(death_row, 283 sk, port, 284 &tw)) 285 goto ok; 286 goto next_port; 287 } 288 } 289 290 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep, 291 head, port); 292 if (!tb) { 293 spin_unlock(&head->lock); 294 break; 295 } 296 tb->fastreuse = -1; 297 goto ok; 298 299 next_port: 300 spin_unlock(&head->lock); 301 } 302 local_bh_enable(); 303 304 return -EADDRNOTAVAIL; 305 306 ok: 307 hint += i; 308 309 /* Head lock still held and bh's disabled */ 310 inet_bind_hash(sk, tb, port); 311 if (sk_unhashed(sk)) { 312 inet_sk(sk)->sport = htons(port); 313 __inet6_hash(hinfo, sk); 314 } 315 spin_unlock(&head->lock); 316 317 if (tw) { 318 inet_twsk_deschedule(tw, death_row); 319 inet_twsk_put(tw); 320 } 321 322 ret = 0; 323 goto out; 324 } 325 326 head = &hinfo->bhash[inet_bhashfn(snum, hinfo->bhash_size)]; 327 tb = inet_csk(sk)->icsk_bind_hash; 328 spin_lock_bh(&head->lock); 329 330 if (sk_head(&tb->owners) == sk && sk->sk_bind_node.next == NULL) { 331 __inet6_hash(hinfo, sk); 332 spin_unlock_bh(&head->lock); 333 return 0; 334 } else { 335 spin_unlock(&head->lock); 336 /* No definite answer... Walk to established hash table */ 337 ret = __inet6_check_established(death_row, sk, snum, NULL); 338 out: 339 local_bh_enable(); 340 return ret; 341 } 342 } 343 344 EXPORT_SYMBOL_GPL(inet6_hash_connect); 345