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/hotdata.h> 18 #include <net/inet_connection_sock.h> 19 #include <net/inet_hashtables.h> 20 #include <net/inet6_hashtables.h> 21 #include <net/secure_seq.h> 22 #include <net/ip.h> 23 #include <net/sock_reuseport.h> 24 #include <net/tcp.h> 25 26 u32 inet6_ehashfn(const struct net *net, 27 const struct in6_addr *laddr, const u16 lport, 28 const struct in6_addr *faddr, const __be16 fport) 29 { 30 u32 lhash, fhash; 31 32 net_get_random_once(&inet6_ehash_secret, sizeof(inet6_ehash_secret)); 33 net_get_random_once(&tcp_ipv6_hash_secret, sizeof(tcp_ipv6_hash_secret)); 34 35 lhash = (__force u32)laddr->s6_addr32[3]; 36 fhash = __ipv6_addr_jhash(faddr, tcp_ipv6_hash_secret); 37 38 return lport + __inet6_ehashfn(lhash, 0, fhash, fport, 39 inet6_ehash_secret + net_hash_mix(net)); 40 } 41 EXPORT_SYMBOL_GPL(inet6_ehashfn); 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(const struct net *net, 50 const struct in6_addr *saddr, 51 const __be16 sport, 52 const struct in6_addr *daddr, 53 const u16 hnum, 54 const int dif, const int sdif) 55 { 56 const __portpair ports = INET_COMBINED_PORTS(sport, hnum); 57 const struct hlist_nulls_node *node; 58 struct inet_ehash_bucket *head; 59 struct inet_hashinfo *hashinfo; 60 unsigned int hash, slot; 61 struct sock *sk; 62 63 hashinfo = net->ipv4.tcp_death_row.hashinfo; 64 hash = inet6_ehashfn(net, daddr, hnum, saddr, sport); 65 slot = hash & hashinfo->ehash_mask; 66 head = &hashinfo->ehash[slot]; 67 begin: 68 sk_nulls_for_each_rcu(sk, node, &head->chain) { 69 if (sk->sk_hash != hash) 70 continue; 71 if (!inet6_match(net, sk, saddr, daddr, ports, dif, sdif)) 72 continue; 73 if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt))) 74 goto out; 75 76 if (unlikely(!inet6_match(net, sk, saddr, daddr, ports, dif, sdif))) { 77 sock_gen_put(sk); 78 goto begin; 79 } 80 goto found; 81 } 82 if (get_nulls_value(node) != slot) 83 goto begin; 84 out: 85 sk = NULL; 86 found: 87 return sk; 88 } 89 EXPORT_SYMBOL(__inet6_lookup_established); 90 91 static inline int compute_score(struct sock *sk, const struct net *net, 92 const unsigned short hnum, 93 const struct in6_addr *daddr, 94 const int dif, const int sdif) 95 { 96 int score = -1; 97 98 if (net_eq(sock_net(sk), net) && inet_sk(sk)->inet_num == hnum && 99 sk->sk_family == PF_INET6) { 100 if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr)) 101 return -1; 102 103 if (!inet_sk_bound_dev_eq(net, sk->sk_bound_dev_if, dif, sdif)) 104 return -1; 105 106 score = sk->sk_bound_dev_if ? 2 : 1; 107 if (READ_ONCE(sk->sk_incoming_cpu) == raw_smp_processor_id()) 108 score++; 109 } 110 return score; 111 } 112 113 /** 114 * inet6_lookup_reuseport() - execute reuseport logic on AF_INET6 socket if necessary. 115 * @net: network namespace. 116 * @sk: AF_INET6 socket, must be in TCP_LISTEN state for TCP or TCP_CLOSE for UDP. 117 * @skb: context for a potential SK_REUSEPORT program. 118 * @doff: header offset. 119 * @saddr: source address. 120 * @sport: source port. 121 * @daddr: destination address. 122 * @hnum: destination port in host byte order. 123 * @ehashfn: hash function used to generate the fallback hash. 124 * 125 * Return: NULL if sk doesn't have SO_REUSEPORT set, otherwise a pointer to 126 * the selected sock or an error. 127 */ 128 struct sock *inet6_lookup_reuseport(const struct net *net, struct sock *sk, 129 struct sk_buff *skb, int doff, 130 const struct in6_addr *saddr, 131 __be16 sport, 132 const struct in6_addr *daddr, 133 unsigned short hnum, 134 inet6_ehashfn_t *ehashfn) 135 { 136 struct sock *reuse_sk = NULL; 137 u32 phash; 138 139 if (sk->sk_reuseport) { 140 phash = INDIRECT_CALL_INET(ehashfn, udp6_ehashfn, inet6_ehashfn, 141 net, daddr, hnum, saddr, sport); 142 reuse_sk = reuseport_select_sock(sk, phash, skb, doff); 143 } 144 return reuse_sk; 145 } 146 EXPORT_SYMBOL_GPL(inet6_lookup_reuseport); 147 148 /* called with rcu_read_lock() */ 149 static struct sock *inet6_lhash2_lookup(const struct net *net, 150 struct inet_listen_hashbucket *ilb2, 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 sock *sk, *result = NULL; 157 struct hlist_nulls_node *node; 158 int score, hiscore = 0; 159 160 sk_nulls_for_each_rcu(sk, node, &ilb2->nulls_head) { 161 score = compute_score(sk, net, hnum, daddr, dif, sdif); 162 if (score > hiscore) { 163 result = inet6_lookup_reuseport(net, sk, skb, doff, 164 saddr, sport, daddr, hnum, inet6_ehashfn); 165 if (result) 166 return result; 167 168 result = sk; 169 hiscore = score; 170 } 171 } 172 173 return result; 174 } 175 176 struct sock *inet6_lookup_run_sk_lookup(const struct net *net, 177 int protocol, 178 struct sk_buff *skb, int doff, 179 const struct in6_addr *saddr, 180 const __be16 sport, 181 const struct in6_addr *daddr, 182 const u16 hnum, const int dif, 183 inet6_ehashfn_t *ehashfn) 184 { 185 struct sock *sk, *reuse_sk; 186 bool no_reuseport; 187 188 no_reuseport = bpf_sk_lookup_run_v6(net, protocol, saddr, sport, 189 daddr, hnum, dif, &sk); 190 if (no_reuseport || IS_ERR_OR_NULL(sk)) 191 return sk; 192 193 reuse_sk = inet6_lookup_reuseport(net, sk, skb, doff, 194 saddr, sport, daddr, hnum, ehashfn); 195 if (reuse_sk) 196 sk = reuse_sk; 197 return sk; 198 } 199 EXPORT_SYMBOL_GPL(inet6_lookup_run_sk_lookup); 200 201 struct sock *inet6_lookup_listener(const struct net *net, 202 struct sk_buff *skb, int doff, 203 const struct in6_addr *saddr, 204 const __be16 sport, 205 const struct in6_addr *daddr, 206 const unsigned short hnum, 207 const int dif, const int sdif) 208 { 209 struct inet_listen_hashbucket *ilb2; 210 struct inet_hashinfo *hashinfo; 211 struct sock *result = NULL; 212 unsigned int hash2; 213 214 /* Lookup redirect from BPF */ 215 if (static_branch_unlikely(&bpf_sk_lookup_enabled)) { 216 result = inet6_lookup_run_sk_lookup(net, IPPROTO_TCP, skb, doff, 217 saddr, sport, daddr, hnum, dif, 218 inet6_ehashfn); 219 if (result) 220 goto done; 221 } 222 223 hashinfo = net->ipv4.tcp_death_row.hashinfo; 224 hash2 = ipv6_portaddr_hash(net, daddr, hnum); 225 ilb2 = inet_lhash2_bucket(hashinfo, hash2); 226 227 result = inet6_lhash2_lookup(net, ilb2, skb, doff, 228 saddr, sport, daddr, hnum, 229 dif, sdif); 230 if (result) 231 goto done; 232 233 /* Lookup lhash2 with in6addr_any */ 234 hash2 = ipv6_portaddr_hash(net, &in6addr_any, hnum); 235 ilb2 = inet_lhash2_bucket(hashinfo, hash2); 236 237 result = inet6_lhash2_lookup(net, ilb2, skb, doff, 238 saddr, sport, &in6addr_any, hnum, 239 dif, sdif); 240 done: 241 if (IS_ERR(result)) 242 return NULL; 243 return result; 244 } 245 EXPORT_SYMBOL_GPL(inet6_lookup_listener); 246 247 struct sock *inet6_lookup(const struct net *net, 248 struct sk_buff *skb, int doff, 249 const struct in6_addr *saddr, const __be16 sport, 250 const struct in6_addr *daddr, const __be16 dport, 251 const int dif) 252 { 253 struct sock *sk; 254 bool refcounted; 255 256 sk = __inet6_lookup(net, skb, doff, saddr, sport, daddr, 257 ntohs(dport), dif, 0, &refcounted); 258 if (sk && !refcounted && !refcount_inc_not_zero(&sk->sk_refcnt)) 259 sk = NULL; 260 return sk; 261 } 262 EXPORT_SYMBOL_GPL(inet6_lookup); 263 264 static int __inet6_check_established(struct inet_timewait_death_row *death_row, 265 struct sock *sk, const __u16 lport, 266 struct inet_timewait_sock **twp, 267 bool rcu_lookup, 268 u32 hash) 269 { 270 struct inet_hashinfo *hinfo = death_row->hashinfo; 271 struct inet_sock *inet = inet_sk(sk); 272 const struct in6_addr *daddr = &sk->sk_v6_rcv_saddr; 273 const struct in6_addr *saddr = &sk->sk_v6_daddr; 274 const int dif = sk->sk_bound_dev_if; 275 struct net *net = sock_net(sk); 276 const int sdif = l3mdev_master_ifindex_by_index(net, dif); 277 const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport); 278 struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash); 279 struct inet_timewait_sock *tw = NULL; 280 const struct hlist_nulls_node *node; 281 struct sock *sk2; 282 spinlock_t *lock; 283 284 if (rcu_lookup) { 285 sk_nulls_for_each(sk2, node, &head->chain) { 286 if (sk2->sk_hash != hash || 287 !inet6_match(net, sk2, saddr, daddr, 288 ports, dif, sdif)) 289 continue; 290 if (sk2->sk_state == TCP_TIME_WAIT) 291 break; 292 return -EADDRNOTAVAIL; 293 } 294 return 0; 295 } 296 297 lock = inet_ehash_lockp(hinfo, hash); 298 spin_lock(lock); 299 300 sk_nulls_for_each(sk2, node, &head->chain) { 301 if (sk2->sk_hash != hash) 302 continue; 303 304 if (likely(inet6_match(net, sk2, saddr, daddr, ports, 305 dif, sdif))) { 306 if (sk2->sk_state == TCP_TIME_WAIT) { 307 tw = inet_twsk(sk2); 308 if (tcp_twsk_unique(sk, sk2, twp)) 309 break; 310 } 311 goto not_unique; 312 } 313 } 314 315 /* Must record num and sport now. Otherwise we will see 316 * in hash table socket with a funny identity. 317 */ 318 inet->inet_num = lport; 319 inet->inet_sport = htons(lport); 320 sk->sk_hash = hash; 321 WARN_ON(!sk_unhashed(sk)); 322 __sk_nulls_add_node_rcu(sk, &head->chain); 323 if (tw) { 324 sk_nulls_del_node_init_rcu((struct sock *)tw); 325 __NET_INC_STATS(net, LINUX_MIB_TIMEWAITRECYCLED); 326 } 327 spin_unlock(lock); 328 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 329 330 if (twp) { 331 *twp = tw; 332 } else if (tw) { 333 /* Silly. Should hash-dance instead... */ 334 inet_twsk_deschedule_put(tw); 335 } 336 return 0; 337 338 not_unique: 339 spin_unlock(lock); 340 return -EADDRNOTAVAIL; 341 } 342 343 static u64 inet6_sk_port_offset(const struct sock *sk) 344 { 345 const struct inet_sock *inet = inet_sk(sk); 346 347 return secure_ipv6_port_ephemeral(sk->sk_v6_rcv_saddr.s6_addr32, 348 sk->sk_v6_daddr.s6_addr32, 349 inet->inet_dport); 350 } 351 352 int inet6_hash_connect(struct inet_timewait_death_row *death_row, 353 struct sock *sk) 354 { 355 const struct in6_addr *daddr = &sk->sk_v6_rcv_saddr; 356 const struct in6_addr *saddr = &sk->sk_v6_daddr; 357 const struct inet_sock *inet = inet_sk(sk); 358 const struct net *net = sock_net(sk); 359 u64 port_offset = 0; 360 u32 hash_port0; 361 362 if (!inet_sk(sk)->inet_num) 363 port_offset = inet6_sk_port_offset(sk); 364 365 hash_port0 = inet6_ehashfn(net, daddr, 0, saddr, inet->inet_dport); 366 367 return __inet_hash_connect(death_row, sk, port_offset, hash_port0, 368 __inet6_check_established); 369 } 370 EXPORT_SYMBOL_GPL(inet6_hash_connect); 371