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 hash &= (hashinfo->ehash_size - 1); 41 list = &hashinfo->ehash[hash].chain; 42 lock = &hashinfo->ehash[hash].lock; 43 write_lock(lock); 44 } 45 46 __sk_add_node(sk, list); 47 sock_prot_inc_use(sk->sk_prot); 48 write_unlock(lock); 49 } 50 EXPORT_SYMBOL(__inet6_hash); 51 52 /* 53 * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so 54 * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM 55 * 56 * The sockhash lock must be held as a reader here. 57 */ 58 struct sock *__inet6_lookup_established(struct inet_hashinfo *hashinfo, 59 const struct in6_addr *saddr, 60 const __be16 sport, 61 const struct in6_addr *daddr, 62 const u16 hnum, 63 const int dif) 64 { 65 struct sock *sk; 66 const struct hlist_node *node; 67 const __portpair ports = INET_COMBINED_PORTS(sport, hnum); 68 /* Optimize here for direct hit, only listening connections can 69 * have wildcards anyways. 70 */ 71 unsigned int hash = inet6_ehashfn(daddr, hnum, saddr, sport); 72 struct inet_ehash_bucket *head = inet_ehash_bucket(hashinfo, hash); 73 74 prefetch(head->chain.first); 75 read_lock(&head->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(&head->lock); 96 return NULL; 97 98 hit: 99 sock_hold(sk); 100 read_unlock(&head->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 struct sock *sk2; 179 const struct hlist_node *node; 180 struct inet_timewait_sock *tw; 181 182 prefetch(head->chain.first); 183 write_lock(&head->lock); 184 185 /* Check TIME-WAIT sockets first. */ 186 sk_for_each(sk2, node, &head->twchain) { 187 const struct inet6_timewait_sock *tw6 = inet6_twsk(sk2); 188 189 tw = inet_twsk(sk2); 190 191 if(*((__portpair *)&(tw->tw_dport)) == ports && 192 sk2->sk_family == PF_INET6 && 193 ipv6_addr_equal(&tw6->tw_v6_daddr, saddr) && 194 ipv6_addr_equal(&tw6->tw_v6_rcv_saddr, daddr) && 195 sk2->sk_bound_dev_if == sk->sk_bound_dev_if) { 196 if (twsk_unique(sk, sk2, twp)) 197 goto unique; 198 else 199 goto not_unique; 200 } 201 } 202 tw = NULL; 203 204 /* And established part... */ 205 sk_for_each(sk2, node, &head->chain) { 206 if (INET6_MATCH(sk2, hash, saddr, daddr, ports, dif)) 207 goto not_unique; 208 } 209 210 unique: 211 /* Must record num and sport now. Otherwise we will see 212 * in hash table socket with a funny identity. */ 213 inet->num = lport; 214 inet->sport = htons(lport); 215 BUG_TRAP(sk_unhashed(sk)); 216 __sk_add_node(sk, &head->chain); 217 sk->sk_hash = hash; 218 sock_prot_inc_use(sk->sk_prot); 219 write_unlock(&head->lock); 220 221 if (twp != NULL) { 222 *twp = tw; 223 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED); 224 } else if (tw != NULL) { 225 /* Silly. Should hash-dance instead... */ 226 inet_twsk_deschedule(tw, death_row); 227 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED); 228 229 inet_twsk_put(tw); 230 } 231 return 0; 232 233 not_unique: 234 write_unlock(&head->lock); 235 return -EADDRNOTAVAIL; 236 } 237 238 static inline u32 inet6_sk_port_offset(const struct sock *sk) 239 { 240 const struct inet_sock *inet = inet_sk(sk); 241 const struct ipv6_pinfo *np = inet6_sk(sk); 242 return secure_ipv6_port_ephemeral(np->rcv_saddr.s6_addr32, 243 np->daddr.s6_addr32, 244 inet->dport); 245 } 246 247 int inet6_hash_connect(struct inet_timewait_death_row *death_row, 248 struct sock *sk) 249 { 250 struct inet_hashinfo *hinfo = death_row->hashinfo; 251 const unsigned short snum = inet_sk(sk)->num; 252 struct inet_bind_hashbucket *head; 253 struct inet_bind_bucket *tb; 254 int ret; 255 256 if (snum == 0) { 257 int i, port, low, high, remaining; 258 static u32 hint; 259 const u32 offset = hint + inet6_sk_port_offset(sk); 260 struct hlist_node *node; 261 struct inet_timewait_sock *tw = NULL; 262 263 inet_get_local_port_range(&low, &high); 264 remaining = (high - low) + 1; 265 266 local_bh_disable(); 267 for (i = 1; i <= remaining; i++) { 268 port = low + (i + offset) % remaining; 269 head = &hinfo->bhash[inet_bhashfn(port, hinfo->bhash_size)]; 270 spin_lock(&head->lock); 271 272 /* Does not bother with rcv_saddr checks, 273 * because the established check is already 274 * unique enough. 275 */ 276 inet_bind_bucket_for_each(tb, node, &head->chain) { 277 if (tb->port == port) { 278 BUG_TRAP(!hlist_empty(&tb->owners)); 279 if (tb->fastreuse >= 0) 280 goto next_port; 281 if (!__inet6_check_established(death_row, 282 sk, port, 283 &tw)) 284 goto ok; 285 goto next_port; 286 } 287 } 288 289 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep, 290 head, port); 291 if (!tb) { 292 spin_unlock(&head->lock); 293 break; 294 } 295 tb->fastreuse = -1; 296 goto ok; 297 298 next_port: 299 spin_unlock(&head->lock); 300 } 301 local_bh_enable(); 302 303 return -EADDRNOTAVAIL; 304 305 ok: 306 hint += i; 307 308 /* Head lock still held and bh's disabled */ 309 inet_bind_hash(sk, tb, port); 310 if (sk_unhashed(sk)) { 311 inet_sk(sk)->sport = htons(port); 312 __inet6_hash(hinfo, sk); 313 } 314 spin_unlock(&head->lock); 315 316 if (tw) { 317 inet_twsk_deschedule(tw, death_row); 318 inet_twsk_put(tw); 319 } 320 321 ret = 0; 322 goto out; 323 } 324 325 head = &hinfo->bhash[inet_bhashfn(snum, hinfo->bhash_size)]; 326 tb = inet_csk(sk)->icsk_bind_hash; 327 spin_lock_bh(&head->lock); 328 329 if (sk_head(&tb->owners) == sk && sk->sk_bind_node.next == NULL) { 330 __inet6_hash(hinfo, sk); 331 spin_unlock_bh(&head->lock); 332 return 0; 333 } else { 334 spin_unlock(&head->lock); 335 /* No definite answer... Walk to established hash table */ 336 ret = __inet6_check_established(death_row, sk, snum, NULL); 337 out: 338 local_bh_enable(); 339 return ret; 340 } 341 } 342 343 EXPORT_SYMBOL_GPL(inet6_hash_connect); 344