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/config.h> 18 #include <linux/module.h> 19 #include <linux/random.h> 20 21 #include <net/inet_connection_sock.h> 22 #include <net/inet_hashtables.h> 23 #include <net/inet6_hashtables.h> 24 #include <net/ip.h> 25 26 void __inet6_hash(struct inet_hashinfo *hashinfo, 27 struct sock *sk) 28 { 29 struct hlist_head *list; 30 rwlock_t *lock; 31 32 BUG_TRAP(sk_unhashed(sk)); 33 34 if (sk->sk_state == TCP_LISTEN) { 35 list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)]; 36 lock = &hashinfo->lhash_lock; 37 inet_listen_wlock(hashinfo); 38 } else { 39 unsigned int hash; 40 sk->sk_hash = hash = inet6_sk_ehashfn(sk); 41 hash &= (hashinfo->ehash_size - 1); 42 list = &hashinfo->ehash[hash].chain; 43 lock = &hashinfo->ehash[hash].lock; 44 write_lock(lock); 45 } 46 47 __sk_add_node(sk, list); 48 sock_prot_inc_use(sk->sk_prot); 49 write_unlock(lock); 50 } 51 EXPORT_SYMBOL(__inet6_hash); 52 53 /* 54 * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so 55 * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM 56 * 57 * The sockhash lock must be held as a reader here. 58 */ 59 struct sock *__inet6_lookup_established(struct inet_hashinfo *hashinfo, 60 const struct in6_addr *saddr, 61 const u16 sport, 62 const struct in6_addr *daddr, 63 const u16 hnum, 64 const int dif) 65 { 66 struct sock *sk; 67 const struct hlist_node *node; 68 const __u32 ports = INET_COMBINED_PORTS(sport, hnum); 69 /* Optimize here for direct hit, only listening connections can 70 * have wildcards anyways. 71 */ 72 unsigned int hash = inet6_ehashfn(daddr, hnum, saddr, sport); 73 struct inet_ehash_bucket *head = inet_ehash_bucket(hashinfo, hash); 74 75 prefetch(head->chain.first); 76 read_lock(&head->lock); 77 sk_for_each(sk, node, &head->chain) { 78 /* For IPV6 do the cheaper port and family tests first. */ 79 if (INET6_MATCH(sk, hash, saddr, daddr, ports, dif)) 80 goto hit; /* You sunk my battleship! */ 81 } 82 /* Must check for a TIME_WAIT'er before going to listener hash. */ 83 sk_for_each(sk, node, &(head + hashinfo->ehash_size)->chain) { 84 const struct inet_timewait_sock *tw = inet_twsk(sk); 85 86 if(*((__u32 *)&(tw->tw_dport)) == ports && 87 sk->sk_family == PF_INET6) { 88 const struct inet6_timewait_sock *tw6 = inet6_twsk(sk); 89 90 if (ipv6_addr_equal(&tw6->tw_v6_daddr, saddr) && 91 ipv6_addr_equal(&tw6->tw_v6_rcv_saddr, daddr) && 92 (!sk->sk_bound_dev_if || sk->sk_bound_dev_if == dif)) 93 goto hit; 94 } 95 } 96 read_unlock(&head->lock); 97 return NULL; 98 99 hit: 100 sock_hold(sk); 101 read_unlock(&head->lock); 102 return sk; 103 } 104 EXPORT_SYMBOL(__inet6_lookup_established); 105 106 struct sock *inet6_lookup_listener(struct inet_hashinfo *hashinfo, 107 const struct in6_addr *daddr, 108 const unsigned short hnum, const int dif) 109 { 110 struct sock *sk; 111 const struct hlist_node *node; 112 struct sock *result = NULL; 113 int score, hiscore = 0; 114 115 read_lock(&hashinfo->lhash_lock); 116 sk_for_each(sk, node, &hashinfo->listening_hash[inet_lhashfn(hnum)]) { 117 if (inet_sk(sk)->num == hnum && sk->sk_family == PF_INET6) { 118 const struct ipv6_pinfo *np = inet6_sk(sk); 119 120 score = 1; 121 if (!ipv6_addr_any(&np->rcv_saddr)) { 122 if (!ipv6_addr_equal(&np->rcv_saddr, daddr)) 123 continue; 124 score++; 125 } 126 if (sk->sk_bound_dev_if) { 127 if (sk->sk_bound_dev_if != dif) 128 continue; 129 score++; 130 } 131 if (score == 3) { 132 result = sk; 133 break; 134 } 135 if (score > hiscore) { 136 hiscore = score; 137 result = sk; 138 } 139 } 140 } 141 if (result) 142 sock_hold(result); 143 read_unlock(&hashinfo->lhash_lock); 144 return result; 145 } 146 147 EXPORT_SYMBOL_GPL(inet6_lookup_listener); 148 149 struct sock *inet6_lookup(struct inet_hashinfo *hashinfo, 150 const struct in6_addr *saddr, const u16 sport, 151 const struct in6_addr *daddr, const u16 dport, 152 const int dif) 153 { 154 struct sock *sk; 155 156 local_bh_disable(); 157 sk = __inet6_lookup(hashinfo, saddr, sport, daddr, ntohs(dport), dif); 158 local_bh_enable(); 159 160 return sk; 161 } 162 163 EXPORT_SYMBOL_GPL(inet6_lookup); 164 165 static int __inet6_check_established(struct inet_timewait_death_row *death_row, 166 struct sock *sk, const __u16 lport, 167 struct inet_timewait_sock **twp) 168 { 169 struct inet_hashinfo *hinfo = death_row->hashinfo; 170 struct inet_sock *inet = inet_sk(sk); 171 const struct ipv6_pinfo *np = inet6_sk(sk); 172 const struct in6_addr *daddr = &np->rcv_saddr; 173 const struct in6_addr *saddr = &np->daddr; 174 const int dif = sk->sk_bound_dev_if; 175 const u32 ports = INET_COMBINED_PORTS(inet->dport, lport); 176 const unsigned int hash = inet6_ehashfn(daddr, inet->num, saddr, 177 inet->dport); 178 struct inet_ehash_bucket *head = inet_ehash_bucket(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(&head->lock); 185 186 /* Check TIME-WAIT sockets first. */ 187 sk_for_each(sk2, node, &(head + hinfo->ehash_size)->chain) { 188 const struct inet6_timewait_sock *tw6 = inet6_twsk(sk2); 189 190 tw = inet_twsk(sk2); 191 192 if(*((__u32 *)&(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 == sk->sk_bound_dev_if) { 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(&head->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(&head->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 const int low = sysctl_local_port_range[0]; 259 const int high = sysctl_local_port_range[1]; 260 const int range = high - low; 261 int i, port; 262 static u32 hint; 263 const u32 offset = hint + inet6_sk_port_offset(sk); 264 struct hlist_node *node; 265 struct inet_timewait_sock *tw = NULL; 266 267 local_bh_disable(); 268 for (i = 1; i <= range; i++) { 269 port = low + (i + offset) % range; 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