1/* 2 * INET An implementation of the TCP/IP protocol suite for the LINUX 3 * operating system. INET is implemented using the BSD Socket 4 * interface as the means of communication with the user level. 5 * 6 * Authors: Lotsa people, from code originally in tcp 7 * 8 * This program is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU General Public License 10 * as published by the Free Software Foundation; either version 11 * 2 of the License, or (at your option) any later version. 12 */ 13 14#ifndef _INET_HASHTABLES_H 15#define _INET_HASHTABLES_H 16 17 18#include <linux/interrupt.h> 19#include <linux/ip.h> 20#include <linux/ipv6.h> 21#include <linux/list.h> 22#include <linux/slab.h> 23#include <linux/socket.h> 24#include <linux/spinlock.h> 25#include <linux/types.h> 26#include <linux/wait.h> 27#include <linux/vmalloc.h> 28 29#include <net/inet_connection_sock.h> 30#include <net/inet_sock.h> 31#include <net/sock.h> 32#include <net/route.h> 33#include <net/tcp_states.h> 34#include <net/netns/hash.h> 35 36#include <linux/atomic.h> 37#include <asm/byteorder.h> 38 39/* This is for all connections with a full identity, no wildcards. 40 * The 'e' prefix stands for Establish, but we really put all sockets 41 * but LISTEN ones. 42 */ 43struct inet_ehash_bucket { 44 struct hlist_nulls_head chain; 45}; 46 47/* There are a few simple rules, which allow for local port reuse by 48 * an application. In essence: 49 * 50 * 1) Sockets bound to different interfaces may share a local port. 51 * Failing that, goto test 2. 52 * 2) If all sockets have sk->sk_reuse set, and none of them are in 53 * TCP_LISTEN state, the port may be shared. 54 * Failing that, goto test 3. 55 * 3) If all sockets are bound to a specific inet_sk(sk)->rcv_saddr local 56 * address, and none of them are the same, the port may be 57 * shared. 58 * Failing this, the port cannot be shared. 59 * 60 * The interesting point, is test #2. This is what an FTP server does 61 * all day. To optimize this case we use a specific flag bit defined 62 * below. As we add sockets to a bind bucket list, we perform a 63 * check of: (newsk->sk_reuse && (newsk->sk_state != TCP_LISTEN)) 64 * As long as all sockets added to a bind bucket pass this test, 65 * the flag bit will be set. 66 * The resulting situation is that tcp_v[46]_verify_bind() can just check 67 * for this flag bit, if it is set and the socket trying to bind has 68 * sk->sk_reuse set, we don't even have to walk the owners list at all, 69 * we return that it is ok to bind this socket to the requested local port. 70 * 71 * Sounds like a lot of work, but it is worth it. In a more naive 72 * implementation (ie. current FreeBSD etc.) the entire list of ports 73 * must be walked for each data port opened by an ftp server. Needless 74 * to say, this does not scale at all. With a couple thousand FTP 75 * users logged onto your box, isn't it nice to know that new data 76 * ports are created in O(1) time? I thought so. ;-) -DaveM 77 */ 78struct inet_bind_bucket { 79 possible_net_t ib_net; 80 unsigned short port; 81 signed char fastreuse; 82 signed char fastreuseport; 83 kuid_t fastuid; 84 int num_owners; 85 struct hlist_node node; 86 struct hlist_head owners; 87}; 88 89static inline struct net *ib_net(struct inet_bind_bucket *ib) 90{ 91 return read_pnet(&ib->ib_net); 92} 93 94#define inet_bind_bucket_for_each(tb, head) \ 95 hlist_for_each_entry(tb, head, node) 96 97struct inet_bind_hashbucket { 98 spinlock_t lock; 99 struct hlist_head chain; 100}; 101 102/* 103 * Sockets can be hashed in established or listening table 104 * We must use different 'nulls' end-of-chain value for listening 105 * hash table, or we might find a socket that was closed and 106 * reallocated/inserted into established hash table 107 */ 108#define LISTENING_NULLS_BASE (1U << 29) 109struct inet_listen_hashbucket { 110 spinlock_t lock; 111 struct hlist_nulls_head head; 112}; 113 114/* This is for listening sockets, thus all sockets which possess wildcards. */ 115#define INET_LHTABLE_SIZE 32 /* Yes, really, this is all you need. */ 116 117struct inet_hashinfo { 118 /* This is for sockets with full identity only. Sockets here will 119 * always be without wildcards and will have the following invariant: 120 * 121 * TCP_ESTABLISHED <= sk->sk_state < TCP_CLOSE 122 * 123 */ 124 struct inet_ehash_bucket *ehash; 125 spinlock_t *ehash_locks; 126 unsigned int ehash_mask; 127 unsigned int ehash_locks_mask; 128 129 /* Ok, let's try this, I give up, we do need a local binding 130 * TCP hash as well as the others for fast bind/connect. 131 */ 132 struct inet_bind_hashbucket *bhash; 133 134 unsigned int bhash_size; 135 /* 4 bytes hole on 64 bit */ 136 137 struct kmem_cache *bind_bucket_cachep; 138 139 /* All the above members are written once at bootup and 140 * never written again _or_ are predominantly read-access. 141 * 142 * Now align to a new cache line as all the following members 143 * might be often dirty. 144 */ 145 /* All sockets in TCP_LISTEN state will be in here. This is the only 146 * table where wildcard'd TCP sockets can exist. Hash function here 147 * is just local port number. 148 */ 149 struct inet_listen_hashbucket listening_hash[INET_LHTABLE_SIZE] 150 ____cacheline_aligned_in_smp; 151 152 atomic_t bsockets; 153}; 154 155static inline struct inet_ehash_bucket *inet_ehash_bucket( 156 struct inet_hashinfo *hashinfo, 157 unsigned int hash) 158{ 159 return &hashinfo->ehash[hash & hashinfo->ehash_mask]; 160} 161 162static inline spinlock_t *inet_ehash_lockp( 163 struct inet_hashinfo *hashinfo, 164 unsigned int hash) 165{ 166 return &hashinfo->ehash_locks[hash & hashinfo->ehash_locks_mask]; 167} 168 169static inline int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo) 170{ 171 unsigned int i, size = 256; 172#if defined(CONFIG_PROVE_LOCKING) 173 unsigned int nr_pcpus = 2; 174#else 175 unsigned int nr_pcpus = num_possible_cpus(); 176#endif 177 if (nr_pcpus >= 4) 178 size = 512; 179 if (nr_pcpus >= 8) 180 size = 1024; 181 if (nr_pcpus >= 16) 182 size = 2048; 183 if (nr_pcpus >= 32) 184 size = 4096; 185 if (sizeof(spinlock_t) != 0) { 186#ifdef CONFIG_NUMA 187 if (size * sizeof(spinlock_t) > PAGE_SIZE) 188 hashinfo->ehash_locks = vmalloc(size * sizeof(spinlock_t)); 189 else 190#endif 191 hashinfo->ehash_locks = kmalloc(size * sizeof(spinlock_t), 192 GFP_KERNEL); 193 if (!hashinfo->ehash_locks) 194 return ENOMEM; 195 for (i = 0; i < size; i++) 196 spin_lock_init(&hashinfo->ehash_locks[i]); 197 } 198 hashinfo->ehash_locks_mask = size - 1; 199 return 0; 200} 201 202static inline void inet_ehash_locks_free(struct inet_hashinfo *hashinfo) 203{ 204 if (hashinfo->ehash_locks) { 205#ifdef CONFIG_NUMA 206 unsigned int size = (hashinfo->ehash_locks_mask + 1) * 207 sizeof(spinlock_t); 208 if (size > PAGE_SIZE) 209 vfree(hashinfo->ehash_locks); 210 else 211#endif 212 kfree(hashinfo->ehash_locks); 213 hashinfo->ehash_locks = NULL; 214 } 215} 216 217struct inet_bind_bucket * 218inet_bind_bucket_create(struct kmem_cache *cachep, struct net *net, 219 struct inet_bind_hashbucket *head, 220 const unsigned short snum); 221void inet_bind_bucket_destroy(struct kmem_cache *cachep, 222 struct inet_bind_bucket *tb); 223 224static inline u32 inet_bhashfn(const struct net *net, const __u16 lport, 225 const u32 bhash_size) 226{ 227 return (lport + net_hash_mix(net)) & (bhash_size - 1); 228} 229 230void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb, 231 const unsigned short snum); 232 233/* These can have wildcards, don't try too hard. */ 234static inline u32 inet_lhashfn(const struct net *net, const unsigned short num) 235{ 236 return (num + net_hash_mix(net)) & (INET_LHTABLE_SIZE - 1); 237} 238 239static inline int inet_sk_listen_hashfn(const struct sock *sk) 240{ 241 return inet_lhashfn(sock_net(sk), inet_sk(sk)->inet_num); 242} 243 244/* Caller must disable local BH processing. */ 245int __inet_inherit_port(struct sock *sk, struct sock *child); 246 247void inet_put_port(struct sock *sk); 248 249void inet_hashinfo_init(struct inet_hashinfo *h); 250 251int __inet_hash_nolisten(struct sock *sk, struct inet_timewait_sock *tw); 252int __inet_hash(struct sock *sk, struct inet_timewait_sock *tw); 253void inet_hash(struct sock *sk); 254void inet_unhash(struct sock *sk); 255 256struct sock *__inet_lookup_listener(struct net *net, 257 struct inet_hashinfo *hashinfo, 258 const __be32 saddr, const __be16 sport, 259 const __be32 daddr, 260 const unsigned short hnum, 261 const int dif); 262 263static inline struct sock *inet_lookup_listener(struct net *net, 264 struct inet_hashinfo *hashinfo, 265 __be32 saddr, __be16 sport, 266 __be32 daddr, __be16 dport, int dif) 267{ 268 return __inet_lookup_listener(net, hashinfo, saddr, sport, 269 daddr, ntohs(dport), dif); 270} 271 272/* Socket demux engine toys. */ 273/* What happens here is ugly; there's a pair of adjacent fields in 274 struct inet_sock; __be16 dport followed by __u16 num. We want to 275 search by pair, so we combine the keys into a single 32bit value 276 and compare with 32bit value read from &...->dport. Let's at least 277 make sure that it's not mixed with anything else... 278 On 64bit targets we combine comparisons with pair of adjacent __be32 279 fields in the same way. 280*/ 281#ifdef __BIG_ENDIAN 282#define INET_COMBINED_PORTS(__sport, __dport) \ 283 ((__force __portpair)(((__force __u32)(__be16)(__sport) << 16) | (__u32)(__dport))) 284#else /* __LITTLE_ENDIAN */ 285#define INET_COMBINED_PORTS(__sport, __dport) \ 286 ((__force __portpair)(((__u32)(__dport) << 16) | (__force __u32)(__be16)(__sport))) 287#endif 288 289#if (BITS_PER_LONG == 64) 290#ifdef __BIG_ENDIAN 291#define INET_ADDR_COOKIE(__name, __saddr, __daddr) \ 292 const __addrpair __name = (__force __addrpair) ( \ 293 (((__force __u64)(__be32)(__saddr)) << 32) | \ 294 ((__force __u64)(__be32)(__daddr))) 295#else /* __LITTLE_ENDIAN */ 296#define INET_ADDR_COOKIE(__name, __saddr, __daddr) \ 297 const __addrpair __name = (__force __addrpair) ( \ 298 (((__force __u64)(__be32)(__daddr)) << 32) | \ 299 ((__force __u64)(__be32)(__saddr))) 300#endif /* __BIG_ENDIAN */ 301#define INET_MATCH(__sk, __net, __cookie, __saddr, __daddr, __ports, __dif) \ 302 (((__sk)->sk_portpair == (__ports)) && \ 303 ((__sk)->sk_addrpair == (__cookie)) && \ 304 (!(__sk)->sk_bound_dev_if || \ 305 ((__sk)->sk_bound_dev_if == (__dif))) && \ 306 net_eq(sock_net(__sk), (__net))) 307#else /* 32-bit arch */ 308#define INET_ADDR_COOKIE(__name, __saddr, __daddr) \ 309 const int __name __deprecated __attribute__((unused)) 310 311#define INET_MATCH(__sk, __net, __cookie, __saddr, __daddr, __ports, __dif) \ 312 (((__sk)->sk_portpair == (__ports)) && \ 313 ((__sk)->sk_daddr == (__saddr)) && \ 314 ((__sk)->sk_rcv_saddr == (__daddr)) && \ 315 (!(__sk)->sk_bound_dev_if || \ 316 ((__sk)->sk_bound_dev_if == (__dif))) && \ 317 net_eq(sock_net(__sk), (__net))) 318#endif /* 64-bit arch */ 319 320/* 321 * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so we need 322 * not check it for lookups anymore, thanks Alexey. -DaveM 323 * 324 * Local BH must be disabled here. 325 */ 326struct sock *__inet_lookup_established(struct net *net, 327 struct inet_hashinfo *hashinfo, 328 const __be32 saddr, const __be16 sport, 329 const __be32 daddr, const u16 hnum, 330 const int dif); 331 332static inline struct sock * 333 inet_lookup_established(struct net *net, struct inet_hashinfo *hashinfo, 334 const __be32 saddr, const __be16 sport, 335 const __be32 daddr, const __be16 dport, 336 const int dif) 337{ 338 return __inet_lookup_established(net, hashinfo, saddr, sport, daddr, 339 ntohs(dport), dif); 340} 341 342static inline struct sock *__inet_lookup(struct net *net, 343 struct inet_hashinfo *hashinfo, 344 const __be32 saddr, const __be16 sport, 345 const __be32 daddr, const __be16 dport, 346 const int dif) 347{ 348 u16 hnum = ntohs(dport); 349 struct sock *sk = __inet_lookup_established(net, hashinfo, 350 saddr, sport, daddr, hnum, dif); 351 352 return sk ? : __inet_lookup_listener(net, hashinfo, saddr, sport, 353 daddr, hnum, dif); 354} 355 356static inline struct sock *inet_lookup(struct net *net, 357 struct inet_hashinfo *hashinfo, 358 const __be32 saddr, const __be16 sport, 359 const __be32 daddr, const __be16 dport, 360 const int dif) 361{ 362 struct sock *sk; 363 364 local_bh_disable(); 365 sk = __inet_lookup(net, hashinfo, saddr, sport, daddr, dport, dif); 366 local_bh_enable(); 367 368 return sk; 369} 370 371static inline struct sock *__inet_lookup_skb(struct inet_hashinfo *hashinfo, 372 struct sk_buff *skb, 373 const __be16 sport, 374 const __be16 dport) 375{ 376 struct sock *sk = skb_steal_sock(skb); 377 const struct iphdr *iph = ip_hdr(skb); 378 379 if (sk) 380 return sk; 381 else 382 return __inet_lookup(dev_net(skb_dst(skb)->dev), hashinfo, 383 iph->saddr, sport, 384 iph->daddr, dport, inet_iif(skb)); 385} 386 387u32 sk_ehashfn(const struct sock *sk); 388u32 inet6_ehashfn(const struct net *net, 389 const struct in6_addr *laddr, const u16 lport, 390 const struct in6_addr *faddr, const __be16 fport); 391 392static inline void sk_daddr_set(struct sock *sk, __be32 addr) 393{ 394 sk->sk_daddr = addr; /* alias of inet_daddr */ 395#if IS_ENABLED(CONFIG_IPV6) 396 ipv6_addr_set_v4mapped(addr, &sk->sk_v6_daddr); 397#endif 398} 399 400static inline void sk_rcv_saddr_set(struct sock *sk, __be32 addr) 401{ 402 sk->sk_rcv_saddr = addr; /* alias of inet_rcv_saddr */ 403#if IS_ENABLED(CONFIG_IPV6) 404 ipv6_addr_set_v4mapped(addr, &sk->sk_v6_rcv_saddr); 405#endif 406} 407 408int __inet_hash_connect(struct inet_timewait_death_row *death_row, 409 struct sock *sk, u32 port_offset, 410 int (*check_established)(struct inet_timewait_death_row *, 411 struct sock *, __u16, 412 struct inet_timewait_sock **)); 413 414int inet_hash_connect(struct inet_timewait_death_row *death_row, 415 struct sock *sk); 416#endif /* _INET_HASHTABLES_H */ 417