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 EXPORT_SYMBOL_GPL(inet6_ehashfn); 43 44 /* 45 * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so 46 * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM 47 * 48 * The sockhash lock must be held as a reader here. 49 */ 50 struct sock *__inet6_lookup_established(struct net *net, 51 struct inet_hashinfo *hashinfo, 52 const struct in6_addr *saddr, 53 const __be16 sport, 54 const struct in6_addr *daddr, 55 const u16 hnum, 56 const int dif, const int sdif) 57 { 58 struct sock *sk; 59 const struct hlist_nulls_node *node; 60 const __portpair ports = INET_COMBINED_PORTS(sport, hnum); 61 /* Optimize here for direct hit, only listening connections can 62 * have wildcards anyways. 63 */ 64 unsigned int hash = inet6_ehashfn(net, daddr, hnum, saddr, sport); 65 unsigned int slot = hash & hashinfo->ehash_mask; 66 struct inet_ehash_bucket *head = &hashinfo->ehash[slot]; 67 68 69 begin: 70 sk_nulls_for_each_rcu(sk, node, &head->chain) { 71 if (sk->sk_hash != hash) 72 continue; 73 if (!inet6_match(net, sk, saddr, daddr, ports, dif, sdif)) 74 continue; 75 if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt))) 76 goto out; 77 78 if (unlikely(!inet6_match(net, sk, saddr, daddr, ports, dif, sdif))) { 79 sock_gen_put(sk); 80 goto begin; 81 } 82 goto found; 83 } 84 if (get_nulls_value(node) != slot) 85 goto begin; 86 out: 87 sk = NULL; 88 found: 89 return sk; 90 } 91 EXPORT_SYMBOL(__inet6_lookup_established); 92 93 static inline int compute_score(struct sock *sk, struct net *net, 94 const unsigned short hnum, 95 const struct in6_addr *daddr, 96 const int dif, const int sdif) 97 { 98 int score = -1; 99 100 if (net_eq(sock_net(sk), net) && inet_sk(sk)->inet_num == hnum && 101 sk->sk_family == PF_INET6) { 102 if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr)) 103 return -1; 104 105 if (!inet_sk_bound_dev_eq(net, sk->sk_bound_dev_if, dif, sdif)) 106 return -1; 107 108 score = sk->sk_bound_dev_if ? 2 : 1; 109 if (READ_ONCE(sk->sk_incoming_cpu) == raw_smp_processor_id()) 110 score++; 111 } 112 return score; 113 } 114 115 /** 116 * inet6_lookup_reuseport() - execute reuseport logic on AF_INET6 socket if necessary. 117 * @net: network namespace. 118 * @sk: AF_INET6 socket, must be in TCP_LISTEN state for TCP or TCP_CLOSE for UDP. 119 * @skb: context for a potential SK_REUSEPORT program. 120 * @doff: header offset. 121 * @saddr: source address. 122 * @sport: source port. 123 * @daddr: destination address. 124 * @hnum: destination port in host byte order. 125 * @ehashfn: hash function used to generate the fallback hash. 126 * 127 * Return: NULL if sk doesn't have SO_REUSEPORT set, otherwise a pointer to 128 * the selected sock or an error. 129 */ 130 struct sock *inet6_lookup_reuseport(struct net *net, struct sock *sk, 131 struct sk_buff *skb, int doff, 132 const struct in6_addr *saddr, 133 __be16 sport, 134 const struct in6_addr *daddr, 135 unsigned short hnum, 136 inet6_ehashfn_t *ehashfn) 137 { 138 struct sock *reuse_sk = NULL; 139 u32 phash; 140 141 if (sk->sk_reuseport) { 142 phash = INDIRECT_CALL_INET(ehashfn, udp6_ehashfn, inet6_ehashfn, 143 net, daddr, hnum, saddr, sport); 144 reuse_sk = reuseport_select_sock(sk, phash, skb, doff); 145 } 146 return reuse_sk; 147 } 148 EXPORT_SYMBOL_GPL(inet6_lookup_reuseport); 149 150 /* called with rcu_read_lock() */ 151 static struct sock *inet6_lhash2_lookup(struct net *net, 152 struct inet_listen_hashbucket *ilb2, 153 struct sk_buff *skb, int doff, 154 const struct in6_addr *saddr, 155 const __be16 sport, const struct in6_addr *daddr, 156 const unsigned short hnum, const int dif, const int sdif) 157 { 158 struct sock *sk, *result = NULL; 159 struct hlist_nulls_node *node; 160 int score, hiscore = 0; 161 162 sk_nulls_for_each_rcu(sk, node, &ilb2->nulls_head) { 163 score = compute_score(sk, net, hnum, daddr, dif, sdif); 164 if (score > hiscore) { 165 result = inet6_lookup_reuseport(net, sk, skb, doff, 166 saddr, sport, daddr, hnum, inet6_ehashfn); 167 if (result) 168 return result; 169 170 result = sk; 171 hiscore = score; 172 } 173 } 174 175 return result; 176 } 177 178 struct sock *inet6_lookup_run_sk_lookup(struct net *net, 179 int protocol, 180 struct sk_buff *skb, int doff, 181 const struct in6_addr *saddr, 182 const __be16 sport, 183 const struct in6_addr *daddr, 184 const u16 hnum, const int dif, 185 inet6_ehashfn_t *ehashfn) 186 { 187 struct sock *sk, *reuse_sk; 188 bool no_reuseport; 189 190 no_reuseport = bpf_sk_lookup_run_v6(net, protocol, saddr, sport, 191 daddr, hnum, dif, &sk); 192 if (no_reuseport || IS_ERR_OR_NULL(sk)) 193 return sk; 194 195 reuse_sk = inet6_lookup_reuseport(net, sk, skb, doff, 196 saddr, sport, daddr, hnum, ehashfn); 197 if (reuse_sk) 198 sk = reuse_sk; 199 return sk; 200 } 201 EXPORT_SYMBOL_GPL(inet6_lookup_run_sk_lookup); 202 203 struct sock *inet6_lookup_listener(struct net *net, 204 struct inet_hashinfo *hashinfo, 205 struct sk_buff *skb, int doff, 206 const struct in6_addr *saddr, 207 const __be16 sport, const struct in6_addr *daddr, 208 const unsigned short hnum, const int dif, const int sdif) 209 { 210 struct inet_listen_hashbucket *ilb2; 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 hashinfo == net->ipv4.tcp_death_row.hashinfo) { 217 result = inet6_lookup_run_sk_lookup(net, IPPROTO_TCP, skb, doff, 218 saddr, sport, daddr, hnum, dif, 219 inet6_ehashfn); 220 if (result) 221 goto done; 222 } 223 224 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(struct net *net, 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 (twsk_unique(sk, sk2, twp)) 295 break; 296 } 297 goto not_unique; 298 } 299 } 300 301 /* Must record num and sport now. Otherwise we will see 302 * in hash table socket with a funny identity. 303 */ 304 inet->inet_num = lport; 305 inet->inet_sport = htons(lport); 306 sk->sk_hash = hash; 307 WARN_ON(!sk_unhashed(sk)); 308 __sk_nulls_add_node_rcu(sk, &head->chain); 309 if (tw) { 310 sk_nulls_del_node_init_rcu((struct sock *)tw); 311 __NET_INC_STATS(net, LINUX_MIB_TIMEWAITRECYCLED); 312 } 313 spin_unlock(lock); 314 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 315 316 if (twp) { 317 *twp = tw; 318 } else if (tw) { 319 /* Silly. Should hash-dance instead... */ 320 inet_twsk_deschedule_put(tw); 321 } 322 return 0; 323 324 not_unique: 325 spin_unlock(lock); 326 return -EADDRNOTAVAIL; 327 } 328 329 static u64 inet6_sk_port_offset(const struct sock *sk) 330 { 331 const struct inet_sock *inet = inet_sk(sk); 332 333 return secure_ipv6_port_ephemeral(sk->sk_v6_rcv_saddr.s6_addr32, 334 sk->sk_v6_daddr.s6_addr32, 335 inet->inet_dport); 336 } 337 338 int inet6_hash_connect(struct inet_timewait_death_row *death_row, 339 struct sock *sk) 340 { 341 u64 port_offset = 0; 342 343 if (!inet_sk(sk)->inet_num) 344 port_offset = inet6_sk_port_offset(sk); 345 return __inet_hash_connect(death_row, sk, port_offset, 346 __inet6_check_established); 347 } 348 EXPORT_SYMBOL_GPL(inet6_hash_connect); 349 350 int inet6_hash(struct sock *sk) 351 { 352 int err = 0; 353 354 if (sk->sk_state != TCP_CLOSE) 355 err = __inet_hash(sk, NULL); 356 357 return err; 358 } 359 EXPORT_SYMBOL_GPL(inet6_hash); 360