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(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, 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 static inline struct sock *lookup_reuseport(struct net *net, struct sock *sk, 115 struct sk_buff *skb, int doff, 116 const struct in6_addr *saddr, 117 __be16 sport, 118 const struct in6_addr *daddr, 119 unsigned short hnum) 120 { 121 struct sock *reuse_sk = NULL; 122 u32 phash; 123 124 if (sk->sk_reuseport) { 125 phash = inet6_ehashfn(net, daddr, hnum, saddr, sport); 126 reuse_sk = reuseport_select_sock(sk, phash, skb, doff); 127 } 128 return reuse_sk; 129 } 130 131 /* called with rcu_read_lock() */ 132 static struct sock *inet6_lhash2_lookup(struct net *net, 133 struct inet_listen_hashbucket *ilb2, 134 struct sk_buff *skb, int doff, 135 const struct in6_addr *saddr, 136 const __be16 sport, const struct in6_addr *daddr, 137 const unsigned short hnum, const int dif, const int sdif) 138 { 139 struct sock *sk, *result = NULL; 140 struct hlist_nulls_node *node; 141 int score, hiscore = 0; 142 143 sk_nulls_for_each_rcu(sk, node, &ilb2->nulls_head) { 144 score = compute_score(sk, net, hnum, daddr, dif, sdif); 145 if (score > hiscore) { 146 result = lookup_reuseport(net, sk, skb, doff, 147 saddr, sport, daddr, hnum); 148 if (result) 149 return result; 150 151 result = sk; 152 hiscore = score; 153 } 154 } 155 156 return result; 157 } 158 159 static inline struct sock *inet6_lookup_run_bpf(struct net *net, 160 struct inet_hashinfo *hashinfo, 161 struct sk_buff *skb, int doff, 162 const struct in6_addr *saddr, 163 const __be16 sport, 164 const struct in6_addr *daddr, 165 const u16 hnum, const int dif) 166 { 167 struct sock *sk, *reuse_sk; 168 bool no_reuseport; 169 170 if (hashinfo != net->ipv4.tcp_death_row.hashinfo) 171 return NULL; /* only TCP is supported */ 172 173 no_reuseport = bpf_sk_lookup_run_v6(net, IPPROTO_TCP, saddr, sport, 174 daddr, hnum, dif, &sk); 175 if (no_reuseport || IS_ERR_OR_NULL(sk)) 176 return sk; 177 178 reuse_sk = lookup_reuseport(net, sk, skb, doff, saddr, sport, daddr, hnum); 179 if (reuse_sk) 180 sk = reuse_sk; 181 return sk; 182 } 183 184 struct sock *inet6_lookup_listener(struct net *net, 185 struct inet_hashinfo *hashinfo, 186 struct sk_buff *skb, int doff, 187 const struct in6_addr *saddr, 188 const __be16 sport, const struct in6_addr *daddr, 189 const unsigned short hnum, const int dif, const int sdif) 190 { 191 struct inet_listen_hashbucket *ilb2; 192 struct sock *result = NULL; 193 unsigned int hash2; 194 195 /* Lookup redirect from BPF */ 196 if (static_branch_unlikely(&bpf_sk_lookup_enabled)) { 197 result = inet6_lookup_run_bpf(net, hashinfo, skb, doff, 198 saddr, sport, daddr, hnum, dif); 199 if (result) 200 goto done; 201 } 202 203 hash2 = ipv6_portaddr_hash(net, daddr, hnum); 204 ilb2 = inet_lhash2_bucket(hashinfo, hash2); 205 206 result = inet6_lhash2_lookup(net, ilb2, skb, doff, 207 saddr, sport, daddr, hnum, 208 dif, sdif); 209 if (result) 210 goto done; 211 212 /* Lookup lhash2 with in6addr_any */ 213 hash2 = ipv6_portaddr_hash(net, &in6addr_any, hnum); 214 ilb2 = inet_lhash2_bucket(hashinfo, hash2); 215 216 result = inet6_lhash2_lookup(net, ilb2, skb, doff, 217 saddr, sport, &in6addr_any, hnum, 218 dif, sdif); 219 done: 220 if (IS_ERR(result)) 221 return NULL; 222 return result; 223 } 224 EXPORT_SYMBOL_GPL(inet6_lookup_listener); 225 226 struct sock *inet6_lookup(struct net *net, struct inet_hashinfo *hashinfo, 227 struct sk_buff *skb, int doff, 228 const struct in6_addr *saddr, const __be16 sport, 229 const struct in6_addr *daddr, const __be16 dport, 230 const int dif) 231 { 232 struct sock *sk; 233 bool refcounted; 234 235 sk = __inet6_lookup(net, hashinfo, skb, doff, saddr, sport, daddr, 236 ntohs(dport), dif, 0, &refcounted); 237 if (sk && !refcounted && !refcount_inc_not_zero(&sk->sk_refcnt)) 238 sk = NULL; 239 return sk; 240 } 241 EXPORT_SYMBOL_GPL(inet6_lookup); 242 243 static int __inet6_check_established(struct inet_timewait_death_row *death_row, 244 struct sock *sk, const __u16 lport, 245 struct inet_timewait_sock **twp) 246 { 247 struct inet_hashinfo *hinfo = death_row->hashinfo; 248 struct inet_sock *inet = inet_sk(sk); 249 const struct in6_addr *daddr = &sk->sk_v6_rcv_saddr; 250 const struct in6_addr *saddr = &sk->sk_v6_daddr; 251 const int dif = sk->sk_bound_dev_if; 252 struct net *net = sock_net(sk); 253 const int sdif = l3mdev_master_ifindex_by_index(net, dif); 254 const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport); 255 const unsigned int hash = inet6_ehashfn(net, daddr, lport, saddr, 256 inet->inet_dport); 257 struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash); 258 spinlock_t *lock = inet_ehash_lockp(hinfo, hash); 259 struct sock *sk2; 260 const struct hlist_nulls_node *node; 261 struct inet_timewait_sock *tw = NULL; 262 263 spin_lock(lock); 264 265 sk_nulls_for_each(sk2, node, &head->chain) { 266 if (sk2->sk_hash != hash) 267 continue; 268 269 if (likely(inet6_match(net, sk2, saddr, daddr, ports, 270 dif, sdif))) { 271 if (sk2->sk_state == TCP_TIME_WAIT) { 272 tw = inet_twsk(sk2); 273 if (twsk_unique(sk, sk2, twp)) 274 break; 275 } 276 goto not_unique; 277 } 278 } 279 280 /* Must record num and sport now. Otherwise we will see 281 * in hash table socket with a funny identity. 282 */ 283 inet->inet_num = lport; 284 inet->inet_sport = htons(lport); 285 sk->sk_hash = hash; 286 WARN_ON(!sk_unhashed(sk)); 287 __sk_nulls_add_node_rcu(sk, &head->chain); 288 if (tw) { 289 sk_nulls_del_node_init_rcu((struct sock *)tw); 290 __NET_INC_STATS(net, LINUX_MIB_TIMEWAITRECYCLED); 291 } 292 spin_unlock(lock); 293 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1); 294 295 if (twp) { 296 *twp = tw; 297 } else if (tw) { 298 /* Silly. Should hash-dance instead... */ 299 inet_twsk_deschedule_put(tw); 300 } 301 return 0; 302 303 not_unique: 304 spin_unlock(lock); 305 return -EADDRNOTAVAIL; 306 } 307 308 static u64 inet6_sk_port_offset(const struct sock *sk) 309 { 310 const struct inet_sock *inet = inet_sk(sk); 311 312 return secure_ipv6_port_ephemeral(sk->sk_v6_rcv_saddr.s6_addr32, 313 sk->sk_v6_daddr.s6_addr32, 314 inet->inet_dport); 315 } 316 317 int inet6_hash_connect(struct inet_timewait_death_row *death_row, 318 struct sock *sk) 319 { 320 u64 port_offset = 0; 321 322 if (!inet_sk(sk)->inet_num) 323 port_offset = inet6_sk_port_offset(sk); 324 return __inet_hash_connect(death_row, sk, port_offset, 325 __inet6_check_established); 326 } 327 EXPORT_SYMBOL_GPL(inet6_hash_connect); 328 329 int inet6_hash(struct sock *sk) 330 { 331 int err = 0; 332 333 if (sk->sk_state != TCP_CLOSE) 334 err = __inet_hash(sk, NULL); 335 336 return err; 337 } 338 EXPORT_SYMBOL_GPL(inet6_hash); 339