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 * Authors: Lotsa people, from code originally in tcp 8 */ 9 10 #ifndef _INET_HASHTABLES_H 11 #define _INET_HASHTABLES_H 12 13 14 #include <linux/interrupt.h> 15 #include <linux/ip.h> 16 #include <linux/ipv6.h> 17 #include <linux/list.h> 18 #include <linux/slab.h> 19 #include <linux/socket.h> 20 #include <linux/spinlock.h> 21 #include <linux/types.h> 22 #include <linux/wait.h> 23 24 #include <net/inet_connection_sock.h> 25 #include <net/inet_sock.h> 26 #include <net/sock.h> 27 #include <net/route.h> 28 #include <net/tcp_states.h> 29 #include <net/netns/hash.h> 30 31 #include <linux/refcount.h> 32 #include <asm/byteorder.h> 33 34 /* This is for all connections with a full identity, no wildcards. 35 * The 'e' prefix stands for Establish, but we really put all sockets 36 * but LISTEN ones. 37 */ 38 struct inet_ehash_bucket { 39 struct hlist_nulls_head chain; 40 }; 41 42 /* There are a few simple rules, which allow for local port reuse by 43 * an application. In essence: 44 * 45 * 1) Sockets bound to different interfaces may share a local port. 46 * Failing that, goto test 2. 47 * 2) If all sockets have sk->sk_reuse set, and none of them are in 48 * TCP_LISTEN state, the port may be shared. 49 * Failing that, goto test 3. 50 * 3) If all sockets are bound to a specific inet_sk(sk)->rcv_saddr local 51 * address, and none of them are the same, the port may be 52 * shared. 53 * Failing this, the port cannot be shared. 54 * 55 * The interesting point, is test #2. This is what an FTP server does 56 * all day. To optimize this case we use a specific flag bit defined 57 * below. As we add sockets to a bind bucket list, we perform a 58 * check of: (newsk->sk_reuse && (newsk->sk_state != TCP_LISTEN)) 59 * As long as all sockets added to a bind bucket pass this test, 60 * the flag bit will be set. 61 * The resulting situation is that tcp_v[46]_verify_bind() can just check 62 * for this flag bit, if it is set and the socket trying to bind has 63 * sk->sk_reuse set, we don't even have to walk the owners list at all, 64 * we return that it is ok to bind this socket to the requested local port. 65 * 66 * Sounds like a lot of work, but it is worth it. In a more naive 67 * implementation (ie. current FreeBSD etc.) the entire list of ports 68 * must be walked for each data port opened by an ftp server. Needless 69 * to say, this does not scale at all. With a couple thousand FTP 70 * users logged onto your box, isn't it nice to know that new data 71 * ports are created in O(1) time? I thought so. ;-) -DaveM 72 */ 73 #define FASTREUSEPORT_ANY 1 74 #define FASTREUSEPORT_STRICT 2 75 76 struct inet_bind_bucket { 77 possible_net_t ib_net; 78 int l3mdev; 79 unsigned short port; 80 signed char fastreuse; 81 signed char fastreuseport; 82 kuid_t fastuid; 83 #if IS_ENABLED(CONFIG_IPV6) 84 struct in6_addr fast_v6_rcv_saddr; 85 #endif 86 __be32 fast_rcv_saddr; 87 unsigned short fast_sk_family; 88 bool fast_ipv6_only; 89 struct hlist_node node; 90 struct hlist_head owners; 91 }; 92 93 static inline struct net *ib_net(struct inet_bind_bucket *ib) 94 { 95 return read_pnet(&ib->ib_net); 96 } 97 98 #define inet_bind_bucket_for_each(tb, head) \ 99 hlist_for_each_entry(tb, head, node) 100 101 struct inet_bind_hashbucket { 102 spinlock_t lock; 103 struct hlist_head chain; 104 }; 105 106 /* 107 * Sockets can be hashed in established or listening table 108 */ 109 struct inet_listen_hashbucket { 110 spinlock_t lock; 111 unsigned int count; 112 struct hlist_head head; 113 }; 114 115 /* This is for listening sockets, thus all sockets which possess wildcards. */ 116 #define INET_LHTABLE_SIZE 32 /* Yes, really, this is all you need. */ 117 118 struct inet_hashinfo { 119 /* This is for sockets with full identity only. Sockets here will 120 * always be without wildcards and will have the following invariant: 121 * 122 * TCP_ESTABLISHED <= sk->sk_state < TCP_CLOSE 123 * 124 */ 125 struct inet_ehash_bucket *ehash; 126 spinlock_t *ehash_locks; 127 unsigned int ehash_mask; 128 unsigned int ehash_locks_mask; 129 130 /* Ok, let's try this, I give up, we do need a local binding 131 * TCP hash as well as the others for fast bind/connect. 132 */ 133 struct kmem_cache *bind_bucket_cachep; 134 struct inet_bind_hashbucket *bhash; 135 unsigned int bhash_size; 136 137 /* The 2nd listener table hashed by local port and address */ 138 unsigned int lhash2_mask; 139 struct inet_listen_hashbucket *lhash2; 140 141 /* All the above members are written once at bootup and 142 * never written again _or_ are predominantly read-access. 143 * 144 * Now align to a new cache line as all the following members 145 * might be often dirty. 146 */ 147 /* All sockets in TCP_LISTEN state will be in listening_hash. 148 * This is the only table where wildcard'd TCP sockets can 149 * exist. listening_hash is only hashed by local port number. 150 * If lhash2 is initialized, the same socket will also be hashed 151 * to lhash2 by port and address. 152 */ 153 struct inet_listen_hashbucket listening_hash[INET_LHTABLE_SIZE] 154 ____cacheline_aligned_in_smp; 155 }; 156 157 #define inet_lhash2_for_each_icsk_rcu(__icsk, list) \ 158 hlist_for_each_entry_rcu(__icsk, list, icsk_listen_portaddr_node) 159 160 static inline struct inet_listen_hashbucket * 161 inet_lhash2_bucket(struct inet_hashinfo *h, u32 hash) 162 { 163 return &h->lhash2[hash & h->lhash2_mask]; 164 } 165 166 static inline struct inet_ehash_bucket *inet_ehash_bucket( 167 struct inet_hashinfo *hashinfo, 168 unsigned int hash) 169 { 170 return &hashinfo->ehash[hash & hashinfo->ehash_mask]; 171 } 172 173 static inline spinlock_t *inet_ehash_lockp( 174 struct inet_hashinfo *hashinfo, 175 unsigned int hash) 176 { 177 return &hashinfo->ehash_locks[hash & hashinfo->ehash_locks_mask]; 178 } 179 180 int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo); 181 182 static inline void inet_ehash_locks_free(struct inet_hashinfo *hashinfo) 183 { 184 kvfree(hashinfo->ehash_locks); 185 hashinfo->ehash_locks = NULL; 186 } 187 188 static inline bool inet_sk_bound_dev_eq(struct net *net, int bound_dev_if, 189 int dif, int sdif) 190 { 191 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV) 192 return inet_bound_dev_eq(!!net->ipv4.sysctl_tcp_l3mdev_accept, 193 bound_dev_if, dif, sdif); 194 #else 195 return inet_bound_dev_eq(true, bound_dev_if, dif, sdif); 196 #endif 197 } 198 199 struct inet_bind_bucket * 200 inet_bind_bucket_create(struct kmem_cache *cachep, struct net *net, 201 struct inet_bind_hashbucket *head, 202 const unsigned short snum, int l3mdev); 203 void inet_bind_bucket_destroy(struct kmem_cache *cachep, 204 struct inet_bind_bucket *tb); 205 206 static inline u32 inet_bhashfn(const struct net *net, const __u16 lport, 207 const u32 bhash_size) 208 { 209 return (lport + net_hash_mix(net)) & (bhash_size - 1); 210 } 211 212 void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb, 213 const unsigned short snum); 214 215 /* These can have wildcards, don't try too hard. */ 216 static inline u32 inet_lhashfn(const struct net *net, const unsigned short num) 217 { 218 return (num + net_hash_mix(net)) & (INET_LHTABLE_SIZE - 1); 219 } 220 221 static inline int inet_sk_listen_hashfn(const struct sock *sk) 222 { 223 return inet_lhashfn(sock_net(sk), inet_sk(sk)->inet_num); 224 } 225 226 /* Caller must disable local BH processing. */ 227 int __inet_inherit_port(const struct sock *sk, struct sock *child); 228 229 void inet_put_port(struct sock *sk); 230 231 void inet_hashinfo_init(struct inet_hashinfo *h); 232 void inet_hashinfo2_init(struct inet_hashinfo *h, const char *name, 233 unsigned long numentries, int scale, 234 unsigned long low_limit, 235 unsigned long high_limit); 236 int inet_hashinfo2_init_mod(struct inet_hashinfo *h); 237 238 bool inet_ehash_insert(struct sock *sk, struct sock *osk); 239 bool inet_ehash_nolisten(struct sock *sk, struct sock *osk); 240 int __inet_hash(struct sock *sk, struct sock *osk); 241 int inet_hash(struct sock *sk); 242 void inet_unhash(struct sock *sk); 243 244 struct sock *__inet_lookup_listener(struct net *net, 245 struct inet_hashinfo *hashinfo, 246 struct sk_buff *skb, int doff, 247 const __be32 saddr, const __be16 sport, 248 const __be32 daddr, 249 const unsigned short hnum, 250 const int dif, const int sdif); 251 252 static inline struct sock *inet_lookup_listener(struct net *net, 253 struct inet_hashinfo *hashinfo, 254 struct sk_buff *skb, int doff, 255 __be32 saddr, __be16 sport, 256 __be32 daddr, __be16 dport, int dif, int sdif) 257 { 258 return __inet_lookup_listener(net, hashinfo, skb, doff, saddr, sport, 259 daddr, ntohs(dport), dif, sdif); 260 } 261 262 /* Socket demux engine toys. */ 263 /* What happens here is ugly; there's a pair of adjacent fields in 264 struct inet_sock; __be16 dport followed by __u16 num. We want to 265 search by pair, so we combine the keys into a single 32bit value 266 and compare with 32bit value read from &...->dport. Let's at least 267 make sure that it's not mixed with anything else... 268 On 64bit targets we combine comparisons with pair of adjacent __be32 269 fields in the same way. 270 */ 271 #ifdef __BIG_ENDIAN 272 #define INET_COMBINED_PORTS(__sport, __dport) \ 273 ((__force __portpair)(((__force __u32)(__be16)(__sport) << 16) | (__u32)(__dport))) 274 #else /* __LITTLE_ENDIAN */ 275 #define INET_COMBINED_PORTS(__sport, __dport) \ 276 ((__force __portpair)(((__u32)(__dport) << 16) | (__force __u32)(__be16)(__sport))) 277 #endif 278 279 #if (BITS_PER_LONG == 64) 280 #ifdef __BIG_ENDIAN 281 #define INET_ADDR_COOKIE(__name, __saddr, __daddr) \ 282 const __addrpair __name = (__force __addrpair) ( \ 283 (((__force __u64)(__be32)(__saddr)) << 32) | \ 284 ((__force __u64)(__be32)(__daddr))) 285 #else /* __LITTLE_ENDIAN */ 286 #define INET_ADDR_COOKIE(__name, __saddr, __daddr) \ 287 const __addrpair __name = (__force __addrpair) ( \ 288 (((__force __u64)(__be32)(__daddr)) << 32) | \ 289 ((__force __u64)(__be32)(__saddr))) 290 #endif /* __BIG_ENDIAN */ 291 #define INET_MATCH(__sk, __net, __cookie, __saddr, __daddr, __ports, __dif, __sdif) \ 292 (((__sk)->sk_portpair == (__ports)) && \ 293 ((__sk)->sk_addrpair == (__cookie)) && \ 294 (((__sk)->sk_bound_dev_if == (__dif)) || \ 295 ((__sk)->sk_bound_dev_if == (__sdif))) && \ 296 net_eq(sock_net(__sk), (__net))) 297 #else /* 32-bit arch */ 298 #define INET_ADDR_COOKIE(__name, __saddr, __daddr) \ 299 const int __name __deprecated __attribute__((unused)) 300 301 #define INET_MATCH(__sk, __net, __cookie, __saddr, __daddr, __ports, __dif, __sdif) \ 302 (((__sk)->sk_portpair == (__ports)) && \ 303 ((__sk)->sk_daddr == (__saddr)) && \ 304 ((__sk)->sk_rcv_saddr == (__daddr)) && \ 305 (((__sk)->sk_bound_dev_if == (__dif)) || \ 306 ((__sk)->sk_bound_dev_if == (__sdif))) && \ 307 net_eq(sock_net(__sk), (__net))) 308 #endif /* 64-bit arch */ 309 310 /* Sockets in TCP_CLOSE state are _always_ taken out of the hash, so we need 311 * not check it for lookups anymore, thanks Alexey. -DaveM 312 */ 313 struct sock *__inet_lookup_established(struct net *net, 314 struct inet_hashinfo *hashinfo, 315 const __be32 saddr, const __be16 sport, 316 const __be32 daddr, const u16 hnum, 317 const int dif, const int sdif); 318 319 static inline struct sock * 320 inet_lookup_established(struct net *net, struct inet_hashinfo *hashinfo, 321 const __be32 saddr, const __be16 sport, 322 const __be32 daddr, const __be16 dport, 323 const int dif) 324 { 325 return __inet_lookup_established(net, hashinfo, saddr, sport, daddr, 326 ntohs(dport), dif, 0); 327 } 328 329 static inline struct sock *__inet_lookup(struct net *net, 330 struct inet_hashinfo *hashinfo, 331 struct sk_buff *skb, int doff, 332 const __be32 saddr, const __be16 sport, 333 const __be32 daddr, const __be16 dport, 334 const int dif, const int sdif, 335 bool *refcounted) 336 { 337 u16 hnum = ntohs(dport); 338 struct sock *sk; 339 340 sk = __inet_lookup_established(net, hashinfo, saddr, sport, 341 daddr, hnum, dif, sdif); 342 *refcounted = true; 343 if (sk) 344 return sk; 345 *refcounted = false; 346 return __inet_lookup_listener(net, hashinfo, skb, doff, saddr, 347 sport, daddr, hnum, dif, sdif); 348 } 349 350 static inline struct sock *inet_lookup(struct net *net, 351 struct inet_hashinfo *hashinfo, 352 struct sk_buff *skb, int doff, 353 const __be32 saddr, const __be16 sport, 354 const __be32 daddr, const __be16 dport, 355 const int dif) 356 { 357 struct sock *sk; 358 bool refcounted; 359 360 sk = __inet_lookup(net, hashinfo, skb, doff, saddr, sport, daddr, 361 dport, dif, 0, &refcounted); 362 363 if (sk && !refcounted && !refcount_inc_not_zero(&sk->sk_refcnt)) 364 sk = NULL; 365 return sk; 366 } 367 368 static inline struct sock *__inet_lookup_skb(struct inet_hashinfo *hashinfo, 369 struct sk_buff *skb, 370 int doff, 371 const __be16 sport, 372 const __be16 dport, 373 const int sdif, 374 bool *refcounted) 375 { 376 struct sock *sk = skb_steal_sock(skb); 377 const struct iphdr *iph = ip_hdr(skb); 378 379 *refcounted = true; 380 if (sk) 381 return sk; 382 383 return __inet_lookup(dev_net(skb_dst(skb)->dev), hashinfo, skb, 384 doff, iph->saddr, sport, 385 iph->daddr, dport, inet_iif(skb), sdif, 386 refcounted); 387 } 388 389 u32 inet6_ehashfn(const struct net *net, 390 const struct in6_addr *laddr, const u16 lport, 391 const struct in6_addr *faddr, const __be16 fport); 392 393 static inline void sk_daddr_set(struct sock *sk, __be32 addr) 394 { 395 sk->sk_daddr = addr; /* alias of inet_daddr */ 396 #if IS_ENABLED(CONFIG_IPV6) 397 ipv6_addr_set_v4mapped(addr, &sk->sk_v6_daddr); 398 #endif 399 } 400 401 static inline void sk_rcv_saddr_set(struct sock *sk, __be32 addr) 402 { 403 sk->sk_rcv_saddr = addr; /* alias of inet_rcv_saddr */ 404 #if IS_ENABLED(CONFIG_IPV6) 405 ipv6_addr_set_v4mapped(addr, &sk->sk_v6_rcv_saddr); 406 #endif 407 } 408 409 int __inet_hash_connect(struct inet_timewait_death_row *death_row, 410 struct sock *sk, u32 port_offset, 411 int (*check_established)(struct inet_timewait_death_row *, 412 struct sock *, __u16, 413 struct inet_timewait_sock **)); 414 415 int inet_hash_connect(struct inet_timewait_death_row *death_row, 416 struct sock *sk); 417 #endif /* _INET_HASHTABLES_H */ 418