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 __inet6_ehashfn(lhash, lport, 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 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(net, sk, 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(net, sk, 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, const struct net *net, 93 const unsigned short hnum, 94 const struct in6_addr *daddr, 95 const int dif, const int sdif) 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 = sk->sk_bound_dev_if ? 2 : 1; 108 if (READ_ONCE(sk->sk_incoming_cpu) == raw_smp_processor_id()) 109 score++; 110 } 111 return score; 112 } 113 114 /** 115 * inet6_lookup_reuseport() - execute reuseport logic on AF_INET6 socket if necessary. 116 * @net: network namespace. 117 * @sk: AF_INET6 socket, must be in TCP_LISTEN state for TCP or TCP_CLOSE for UDP. 118 * @skb: context for a potential SK_REUSEPORT program. 119 * @doff: header offset. 120 * @saddr: source address. 121 * @sport: source port. 122 * @daddr: destination address. 123 * @hnum: destination port in host byte order. 124 * @ehashfn: hash function used to generate the fallback hash. 125 * 126 * Return: NULL if sk doesn't have SO_REUSEPORT set, otherwise a pointer to 127 * the selected sock or an error. 128 */ 129 struct sock *inet6_lookup_reuseport(const struct net *net, struct sock *sk, 130 struct sk_buff *skb, int doff, 131 const struct in6_addr *saddr, 132 __be16 sport, 133 const struct in6_addr *daddr, 134 unsigned short hnum, 135 inet6_ehashfn_t *ehashfn) 136 { 137 struct sock *reuse_sk = NULL; 138 u32 phash; 139 140 if (sk->sk_reuseport) { 141 phash = INDIRECT_CALL_INET(ehashfn, udp6_ehashfn, inet6_ehashfn, 142 net, daddr, hnum, saddr, sport); 143 reuse_sk = reuseport_select_sock(sk, phash, skb, doff); 144 } 145 return reuse_sk; 146 } 147 EXPORT_SYMBOL_GPL(inet6_lookup_reuseport); 148 149 /* called with rcu_read_lock() */ 150 static struct sock *inet6_lhash2_lookup(const struct net *net, 151 struct inet_listen_hashbucket *ilb2, 152 struct sk_buff *skb, int doff, 153 const struct in6_addr *saddr, 154 const __be16 sport, const struct in6_addr *daddr, 155 const unsigned short hnum, const int dif, const int sdif) 156 { 157 struct sock *sk, *result = NULL; 158 struct hlist_nulls_node *node; 159 int score, hiscore = 0; 160 161 sk_nulls_for_each_rcu(sk, node, &ilb2->nulls_head) { 162 score = compute_score(sk, net, hnum, daddr, dif, sdif); 163 if (score > hiscore) { 164 result = inet6_lookup_reuseport(net, sk, skb, doff, 165 saddr, sport, daddr, hnum, inet6_ehashfn); 166 if (result) 167 return result; 168 169 result = sk; 170 hiscore = score; 171 } 172 } 173 174 return result; 175 } 176 177 struct sock *inet6_lookup_run_sk_lookup(const struct net *net, 178 int protocol, 179 struct sk_buff *skb, int doff, 180 const struct in6_addr *saddr, 181 const __be16 sport, 182 const struct in6_addr *daddr, 183 const u16 hnum, const int dif, 184 inet6_ehashfn_t *ehashfn) 185 { 186 struct sock *sk, *reuse_sk; 187 bool no_reuseport; 188 189 no_reuseport = bpf_sk_lookup_run_v6(net, protocol, saddr, sport, 190 daddr, hnum, dif, &sk); 191 if (no_reuseport || IS_ERR_OR_NULL(sk)) 192 return sk; 193 194 reuse_sk = inet6_lookup_reuseport(net, sk, skb, doff, 195 saddr, sport, daddr, hnum, ehashfn); 196 if (reuse_sk) 197 sk = reuse_sk; 198 return sk; 199 } 200 EXPORT_SYMBOL_GPL(inet6_lookup_run_sk_lookup); 201 202 struct sock *inet6_lookup_listener(const struct net *net, 203 struct inet_hashinfo *hashinfo, 204 struct sk_buff *skb, int doff, 205 const struct in6_addr *saddr, 206 const __be16 sport, const struct in6_addr *daddr, 207 const unsigned short hnum, const int dif, const int sdif) 208 { 209 struct inet_listen_hashbucket *ilb2; 210 struct sock *result = NULL; 211 unsigned int hash2; 212 213 /* Lookup redirect from BPF */ 214 if (static_branch_unlikely(&bpf_sk_lookup_enabled) && 215 hashinfo == net->ipv4.tcp_death_row.hashinfo) { 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 hash2 = ipv6_portaddr_hash(net, daddr, hnum); 224 ilb2 = inet_lhash2_bucket(hashinfo, hash2); 225 226 result = inet6_lhash2_lookup(net, ilb2, skb, doff, 227 saddr, sport, daddr, hnum, 228 dif, sdif); 229 if (result) 230 goto done; 231 232 /* Lookup lhash2 with in6addr_any */ 233 hash2 = ipv6_portaddr_hash(net, &in6addr_any, hnum); 234 ilb2 = inet_lhash2_bucket(hashinfo, hash2); 235 236 result = inet6_lhash2_lookup(net, ilb2, skb, doff, 237 saddr, sport, &in6addr_any, hnum, 238 dif, sdif); 239 done: 240 if (IS_ERR(result)) 241 return NULL; 242 return result; 243 } 244 EXPORT_SYMBOL_GPL(inet6_lookup_listener); 245 246 struct sock *inet6_lookup(const struct net *net, 247 struct inet_hashinfo *hashinfo, 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, hashinfo, 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 { 268 struct inet_hashinfo *hinfo = death_row->hashinfo; 269 struct inet_sock *inet = inet_sk(sk); 270 const struct in6_addr *daddr = &sk->sk_v6_rcv_saddr; 271 const struct in6_addr *saddr = &sk->sk_v6_daddr; 272 const int dif = sk->sk_bound_dev_if; 273 struct net *net = sock_net(sk); 274 const int sdif = l3mdev_master_ifindex_by_index(net, dif); 275 const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport); 276 const unsigned int hash = inet6_ehashfn(net, daddr, lport, saddr, 277 inet->inet_dport); 278 struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash); 279 spinlock_t *lock = inet_ehash_lockp(hinfo, hash); 280 struct sock *sk2; 281 const struct hlist_nulls_node *node; 282 struct inet_timewait_sock *tw = NULL; 283 284 spin_lock(lock); 285 286 sk_nulls_for_each(sk2, node, &head->chain) { 287 if (sk2->sk_hash != hash) 288 continue; 289 290 if (likely(inet6_match(net, sk2, saddr, daddr, ports, 291 dif, sdif))) { 292 if (sk2->sk_state == TCP_TIME_WAIT) { 293 tw = inet_twsk(sk2); 294 if (sk->sk_protocol == IPPROTO_TCP && 295 tcp_twsk_unique(sk, sk2, twp)) 296 break; 297 } 298 goto not_unique; 299 } 300 } 301 302 /* Must record num and sport now. Otherwise we will see 303 * in hash table socket with a funny identity. 304 */ 305 inet->inet_num = lport; 306 inet->inet_sport = htons(lport); 307 sk->sk_hash = hash; 308 WARN_ON(!sk_unhashed(sk)); 309 __sk_nulls_add_node_rcu(sk, &head->chain); 310 if (tw) { 311 sk_nulls_del_node_init_rcu((struct sock *)tw); 312 __NET_INC_STATS(net, LINUX_MIB_TIMEWAITRECYCLED); 313 } 314 spin_unlock(lock); 315 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 316 317 if (twp) { 318 *twp = tw; 319 } else if (tw) { 320 /* Silly. Should hash-dance instead... */ 321 inet_twsk_deschedule_put(tw); 322 } 323 return 0; 324 325 not_unique: 326 spin_unlock(lock); 327 return -EADDRNOTAVAIL; 328 } 329 330 static u64 inet6_sk_port_offset(const struct sock *sk) 331 { 332 const struct inet_sock *inet = inet_sk(sk); 333 334 return secure_ipv6_port_ephemeral(sk->sk_v6_rcv_saddr.s6_addr32, 335 sk->sk_v6_daddr.s6_addr32, 336 inet->inet_dport); 337 } 338 339 int inet6_hash_connect(struct inet_timewait_death_row *death_row, 340 struct sock *sk) 341 { 342 u64 port_offset = 0; 343 344 if (!inet_sk(sk)->inet_num) 345 port_offset = inet6_sk_port_offset(sk); 346 return __inet_hash_connect(death_row, sk, port_offset, 347 __inet6_check_established); 348 } 349 EXPORT_SYMBOL_GPL(inet6_hash_connect); 350 351 int inet6_hash(struct sock *sk) 352 { 353 int err = 0; 354 355 if (sk->sk_state != TCP_CLOSE) 356 err = __inet_hash(sk, NULL); 357 358 return err; 359 } 360 EXPORT_SYMBOL_GPL(inet6_hash); 361