1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * INET An implementation of the TCP/IP protocol suite for the LINUX 4 * operating system. INET is implemented using the BSD Socket 5 * interface as the means of communication with the user level. 6 * 7 * Generic INET6 transport hashtables 8 * 9 * Authors: Lotsa people, from code originally in tcp, generalised here 10 * by Arnaldo Carvalho de Melo <acme@mandriva.com> 11 */ 12 13 #include <linux/module.h> 14 #include <linux/random.h> 15 16 #include <net/addrconf.h> 17 #include <net/inet_connection_sock.h> 18 #include <net/inet_hashtables.h> 19 #include <net/inet6_hashtables.h> 20 #include <net/secure_seq.h> 21 #include <net/ip.h> 22 #include <net/sock_reuseport.h> 23 24 u32 inet6_ehashfn(const struct net *net, 25 const struct in6_addr *laddr, const u16 lport, 26 const struct in6_addr *faddr, const __be16 fport) 27 { 28 static u32 inet6_ehash_secret __read_mostly; 29 static u32 ipv6_hash_secret __read_mostly; 30 31 u32 lhash, fhash; 32 33 net_get_random_once(&inet6_ehash_secret, sizeof(inet6_ehash_secret)); 34 net_get_random_once(&ipv6_hash_secret, sizeof(ipv6_hash_secret)); 35 36 lhash = (__force u32)laddr->s6_addr32[3]; 37 fhash = __ipv6_addr_jhash(faddr, ipv6_hash_secret); 38 39 return __inet6_ehashfn(lhash, lport, fhash, fport, 40 inet6_ehash_secret + net_hash_mix(net)); 41 } 42 43 /* 44 * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so 45 * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM 46 * 47 * The sockhash lock must be held as a reader here. 48 */ 49 struct sock *__inet6_lookup_established(struct net *net, 50 struct inet_hashinfo *hashinfo, 51 const struct in6_addr *saddr, 52 const __be16 sport, 53 const struct in6_addr *daddr, 54 const u16 hnum, 55 const int dif, const int sdif) 56 { 57 struct sock *sk; 58 const struct hlist_nulls_node *node; 59 const __portpair ports = INET_COMBINED_PORTS(sport, hnum); 60 /* Optimize here for direct hit, only listening connections can 61 * have wildcards anyways. 62 */ 63 unsigned int hash = inet6_ehashfn(net, daddr, hnum, saddr, sport); 64 unsigned int slot = hash & hashinfo->ehash_mask; 65 struct inet_ehash_bucket *head = &hashinfo->ehash[slot]; 66 67 68 begin: 69 sk_nulls_for_each_rcu(sk, node, &head->chain) { 70 if (sk->sk_hash != hash) 71 continue; 72 if (!INET6_MATCH(sk, net, saddr, daddr, ports, dif, sdif)) 73 continue; 74 if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt))) 75 goto out; 76 77 if (unlikely(!INET6_MATCH(sk, net, saddr, daddr, ports, dif, sdif))) { 78 sock_gen_put(sk); 79 goto begin; 80 } 81 goto found; 82 } 83 if (get_nulls_value(node) != slot) 84 goto begin; 85 out: 86 sk = NULL; 87 found: 88 return sk; 89 } 90 EXPORT_SYMBOL(__inet6_lookup_established); 91 92 static inline int compute_score(struct sock *sk, struct net *net, 93 const unsigned short hnum, 94 const struct in6_addr *daddr, 95 const int dif, const int sdif, bool exact_dif) 96 { 97 int score = -1; 98 99 if (net_eq(sock_net(sk), net) && inet_sk(sk)->inet_num == hnum && 100 sk->sk_family == PF_INET6) { 101 if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr)) 102 return -1; 103 104 if (!inet_sk_bound_dev_eq(net, sk->sk_bound_dev_if, dif, sdif)) 105 return -1; 106 107 score = 1; 108 if (sk->sk_incoming_cpu == raw_smp_processor_id()) 109 score++; 110 } 111 return score; 112 } 113 114 /* called with rcu_read_lock() */ 115 static struct sock *inet6_lhash2_lookup(struct net *net, 116 struct inet_listen_hashbucket *ilb2, 117 struct sk_buff *skb, int doff, 118 const struct in6_addr *saddr, 119 const __be16 sport, const struct in6_addr *daddr, 120 const unsigned short hnum, const int dif, const int sdif) 121 { 122 bool exact_dif = inet6_exact_dif_match(net, skb); 123 struct inet_connection_sock *icsk; 124 struct sock *sk, *result = NULL; 125 int score, hiscore = 0; 126 u32 phash = 0; 127 128 inet_lhash2_for_each_icsk_rcu(icsk, &ilb2->head) { 129 sk = (struct sock *)icsk; 130 score = compute_score(sk, net, hnum, daddr, dif, sdif, 131 exact_dif); 132 if (score > hiscore) { 133 if (sk->sk_reuseport) { 134 phash = inet6_ehashfn(net, daddr, hnum, 135 saddr, sport); 136 result = reuseport_select_sock(sk, phash, 137 skb, doff); 138 if (result) 139 return result; 140 } 141 result = sk; 142 hiscore = score; 143 } 144 } 145 146 return result; 147 } 148 149 struct sock *inet6_lookup_listener(struct net *net, 150 struct inet_hashinfo *hashinfo, 151 struct sk_buff *skb, int doff, 152 const struct in6_addr *saddr, 153 const __be16 sport, const struct in6_addr *daddr, 154 const unsigned short hnum, const int dif, const int sdif) 155 { 156 struct inet_listen_hashbucket *ilb2; 157 struct sock *result = NULL; 158 unsigned int hash2; 159 160 hash2 = ipv6_portaddr_hash(net, daddr, hnum); 161 ilb2 = inet_lhash2_bucket(hashinfo, hash2); 162 163 result = inet6_lhash2_lookup(net, ilb2, skb, doff, 164 saddr, sport, daddr, hnum, 165 dif, sdif); 166 if (result) 167 goto done; 168 169 /* Lookup lhash2 with in6addr_any */ 170 hash2 = ipv6_portaddr_hash(net, &in6addr_any, hnum); 171 ilb2 = inet_lhash2_bucket(hashinfo, hash2); 172 173 result = inet6_lhash2_lookup(net, ilb2, skb, doff, 174 saddr, sport, &in6addr_any, hnum, 175 dif, sdif); 176 done: 177 if (IS_ERR(result)) 178 return NULL; 179 return result; 180 } 181 EXPORT_SYMBOL_GPL(inet6_lookup_listener); 182 183 struct sock *inet6_lookup(struct net *net, struct inet_hashinfo *hashinfo, 184 struct sk_buff *skb, int doff, 185 const struct in6_addr *saddr, const __be16 sport, 186 const struct in6_addr *daddr, const __be16 dport, 187 const int dif) 188 { 189 struct sock *sk; 190 bool refcounted; 191 192 sk = __inet6_lookup(net, hashinfo, skb, doff, saddr, sport, daddr, 193 ntohs(dport), dif, 0, &refcounted); 194 if (sk && !refcounted && !refcount_inc_not_zero(&sk->sk_refcnt)) 195 sk = NULL; 196 return sk; 197 } 198 EXPORT_SYMBOL_GPL(inet6_lookup); 199 200 static int __inet6_check_established(struct inet_timewait_death_row *death_row, 201 struct sock *sk, const __u16 lport, 202 struct inet_timewait_sock **twp) 203 { 204 struct inet_hashinfo *hinfo = death_row->hashinfo; 205 struct inet_sock *inet = inet_sk(sk); 206 const struct in6_addr *daddr = &sk->sk_v6_rcv_saddr; 207 const struct in6_addr *saddr = &sk->sk_v6_daddr; 208 const int dif = sk->sk_bound_dev_if; 209 struct net *net = sock_net(sk); 210 const int sdif = l3mdev_master_ifindex_by_index(net, dif); 211 const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport); 212 const unsigned int hash = inet6_ehashfn(net, daddr, lport, saddr, 213 inet->inet_dport); 214 struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash); 215 spinlock_t *lock = inet_ehash_lockp(hinfo, hash); 216 struct sock *sk2; 217 const struct hlist_nulls_node *node; 218 struct inet_timewait_sock *tw = NULL; 219 220 spin_lock(lock); 221 222 sk_nulls_for_each(sk2, node, &head->chain) { 223 if (sk2->sk_hash != hash) 224 continue; 225 226 if (likely(INET6_MATCH(sk2, net, saddr, daddr, ports, 227 dif, sdif))) { 228 if (sk2->sk_state == TCP_TIME_WAIT) { 229 tw = inet_twsk(sk2); 230 if (twsk_unique(sk, sk2, twp)) 231 break; 232 } 233 goto not_unique; 234 } 235 } 236 237 /* Must record num and sport now. Otherwise we will see 238 * in hash table socket with a funny identity. 239 */ 240 inet->inet_num = lport; 241 inet->inet_sport = htons(lport); 242 sk->sk_hash = hash; 243 WARN_ON(!sk_unhashed(sk)); 244 __sk_nulls_add_node_rcu(sk, &head->chain); 245 if (tw) { 246 sk_nulls_del_node_init_rcu((struct sock *)tw); 247 __NET_INC_STATS(net, LINUX_MIB_TIMEWAITRECYCLED); 248 } 249 spin_unlock(lock); 250 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 251 252 if (twp) { 253 *twp = tw; 254 } else if (tw) { 255 /* Silly. Should hash-dance instead... */ 256 inet_twsk_deschedule_put(tw); 257 } 258 return 0; 259 260 not_unique: 261 spin_unlock(lock); 262 return -EADDRNOTAVAIL; 263 } 264 265 static u32 inet6_sk_port_offset(const struct sock *sk) 266 { 267 const struct inet_sock *inet = inet_sk(sk); 268 269 return secure_ipv6_port_ephemeral(sk->sk_v6_rcv_saddr.s6_addr32, 270 sk->sk_v6_daddr.s6_addr32, 271 inet->inet_dport); 272 } 273 274 int inet6_hash_connect(struct inet_timewait_death_row *death_row, 275 struct sock *sk) 276 { 277 u32 port_offset = 0; 278 279 if (!inet_sk(sk)->inet_num) 280 port_offset = inet6_sk_port_offset(sk); 281 return __inet_hash_connect(death_row, sk, port_offset, 282 __inet6_check_established); 283 } 284 EXPORT_SYMBOL_GPL(inet6_hash_connect); 285 286 int inet6_hash(struct sock *sk) 287 { 288 int err = 0; 289 290 if (sk->sk_state != TCP_CLOSE) { 291 local_bh_disable(); 292 err = __inet_hash(sk, NULL); 293 local_bh_enable(); 294 } 295 296 return err; 297 } 298 EXPORT_SYMBOL_GPL(inet6_hash); 299