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 * One chain is dedicated to TIME_WAIT sockets. 41 * I'll experiment with dynamic table growth later. 42 */ 43struct inet_ehash_bucket { 44 struct hlist_nulls_head chain; 45 struct hlist_nulls_head twchain; 46}; 47 48/* There are a few simple rules, which allow for local port reuse by 49 * an application. In essence: 50 * 51 * 1) Sockets bound to different interfaces may share a local port. 52 * Failing that, goto test 2. 53 * 2) If all sockets have sk->sk_reuse set, and none of them are in 54 * TCP_LISTEN state, the port may be shared. 55 * Failing that, goto test 3. 56 * 3) If all sockets are bound to a specific inet_sk(sk)->rcv_saddr local 57 * address, and none of them are the same, the port may be 58 * shared. 59 * Failing this, the port cannot be shared. 60 * 61 * The interesting point, is test #2. This is what an FTP server does 62 * all day. To optimize this case we use a specific flag bit defined 63 * below. As we add sockets to a bind bucket list, we perform a 64 * check of: (newsk->sk_reuse && (newsk->sk_state != TCP_LISTEN)) 65 * As long as all sockets added to a bind bucket pass this test, 66 * the flag bit will be set. 67 * The resulting situation is that tcp_v[46]_verify_bind() can just check 68 * for this flag bit, if it is set and the socket trying to bind has 69 * sk->sk_reuse set, we don't even have to walk the owners list at all, 70 * we return that it is ok to bind this socket to the requested local port. 71 * 72 * Sounds like a lot of work, but it is worth it. In a more naive 73 * implementation (ie. current FreeBSD etc.) the entire list of ports 74 * must be walked for each data port opened by an ftp server. Needless 75 * to say, this does not scale at all. With a couple thousand FTP 76 * users logged onto your box, isn't it nice to know that new data 77 * ports are created in O(1) time? I thought so. ;-) -DaveM 78 */ 79struct inet_bind_bucket { 80#ifdef CONFIG_NET_NS 81 struct net *ib_net; 82#endif 83 unsigned short port; 84 signed short fastreuse; 85 int num_owners; 86 struct hlist_node node; 87 struct hlist_head owners; 88}; 89 90static inline struct net *ib_net(struct inet_bind_bucket *ib) 91{ 92 return read_pnet(&ib->ib_net); 93} 94 95#define inet_bind_bucket_for_each(tb, pos, head) \ 96 hlist_for_each_entry(tb, pos, head, node) 97 98struct inet_bind_hashbucket { 99 spinlock_t lock; 100 struct hlist_head chain; 101}; 102 103/* 104 * Sockets can be hashed in established or listening table 105 * We must use different 'nulls' end-of-chain value for listening 106 * hash table, or we might find a socket that was closed and 107 * reallocated/inserted into established hash table 108 */ 109#define LISTENING_NULLS_BASE (1U << 29) 110struct inet_listen_hashbucket { 111 spinlock_t lock; 112 struct hlist_nulls_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 118struct 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 * TIME_WAIT sockets use a separate chain (twchain). 125 */ 126 struct inet_ehash_bucket *ehash; 127 spinlock_t *ehash_locks; 128 unsigned int ehash_mask; 129 unsigned int ehash_locks_mask; 130 131 /* Ok, let's try this, I give up, we do need a local binding 132 * TCP hash as well as the others for fast bind/connect. 133 */ 134 struct inet_bind_hashbucket *bhash; 135 136 unsigned int bhash_size; 137 /* 4 bytes hole on 64 bit */ 138 139 struct kmem_cache *bind_bucket_cachep; 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 here. This is the only 148 * table where wildcard'd TCP sockets can exist. Hash function here 149 * is just local port number. 150 */ 151 struct inet_listen_hashbucket listening_hash[INET_LHTABLE_SIZE] 152 ____cacheline_aligned_in_smp; 153 154 atomic_t bsockets; 155}; 156 157static inline struct inet_ehash_bucket *inet_ehash_bucket( 158 struct inet_hashinfo *hashinfo, 159 unsigned int hash) 160{ 161 return &hashinfo->ehash[hash & hashinfo->ehash_mask]; 162} 163 164static inline spinlock_t *inet_ehash_lockp( 165 struct inet_hashinfo *hashinfo, 166 unsigned int hash) 167{ 168 return &hashinfo->ehash_locks[hash & hashinfo->ehash_locks_mask]; 169} 170 171static inline int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo) 172{ 173 unsigned int i, size = 256; 174#if defined(CONFIG_PROVE_LOCKING) 175 unsigned int nr_pcpus = 2; 176#else 177 unsigned int nr_pcpus = num_possible_cpus(); 178#endif 179 if (nr_pcpus >= 4) 180 size = 512; 181 if (nr_pcpus >= 8) 182 size = 1024; 183 if (nr_pcpus >= 16) 184 size = 2048; 185 if (nr_pcpus >= 32) 186 size = 4096; 187 if (sizeof(spinlock_t) != 0) { 188#ifdef CONFIG_NUMA 189 if (size * sizeof(spinlock_t) > PAGE_SIZE) 190 hashinfo->ehash_locks = vmalloc(size * sizeof(spinlock_t)); 191 else 192#endif 193 hashinfo->ehash_locks = kmalloc(size * sizeof(spinlock_t), 194 GFP_KERNEL); 195 if (!hashinfo->ehash_locks) 196 return ENOMEM; 197 for (i = 0; i < size; i++) 198 spin_lock_init(&hashinfo->ehash_locks[i]); 199 } 200 hashinfo->ehash_locks_mask = size - 1; 201 return 0; 202} 203 204static inline void inet_ehash_locks_free(struct inet_hashinfo *hashinfo) 205{ 206 if (hashinfo->ehash_locks) { 207#ifdef CONFIG_NUMA 208 unsigned int size = (hashinfo->ehash_locks_mask + 1) * 209 sizeof(spinlock_t); 210 if (size > PAGE_SIZE) 211 vfree(hashinfo->ehash_locks); 212 else 213#endif 214 kfree(hashinfo->ehash_locks); 215 hashinfo->ehash_locks = NULL; 216 } 217} 218 219extern struct inet_bind_bucket * 220 inet_bind_bucket_create(struct kmem_cache *cachep, 221 struct net *net, 222 struct inet_bind_hashbucket *head, 223 const unsigned short snum); 224extern void inet_bind_bucket_destroy(struct kmem_cache *cachep, 225 struct inet_bind_bucket *tb); 226 227static inline int inet_bhashfn(struct net *net, 228 const __u16 lport, const int bhash_size) 229{ 230 return (lport + net_hash_mix(net)) & (bhash_size - 1); 231} 232 233extern void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb, 234 const unsigned short snum); 235 236/* These can have wildcards, don't try too hard. */ 237static inline int inet_lhashfn(struct net *net, const unsigned short num) 238{ 239 return (num + net_hash_mix(net)) & (INET_LHTABLE_SIZE - 1); 240} 241 242static inline int inet_sk_listen_hashfn(const struct sock *sk) 243{ 244 return inet_lhashfn(sock_net(sk), inet_sk(sk)->inet_num); 245} 246 247/* Caller must disable local BH processing. */ 248extern int __inet_inherit_port(struct sock *sk, struct sock *child); 249 250extern void inet_put_port(struct sock *sk); 251 252void inet_hashinfo_init(struct inet_hashinfo *h); 253 254extern int __inet_hash_nolisten(struct sock *sk, struct inet_timewait_sock *tw); 255extern void inet_hash(struct sock *sk); 256extern void inet_unhash(struct sock *sk); 257 258extern struct sock *__inet_lookup_listener(struct net *net, 259 struct inet_hashinfo *hashinfo, 260 const __be32 daddr, 261 const unsigned short hnum, 262 const int dif); 263 264static inline struct sock *inet_lookup_listener(struct net *net, 265 struct inet_hashinfo *hashinfo, 266 __be32 daddr, __be16 dport, int dif) 267{ 268 return __inet_lookup_listener(net, hashinfo, daddr, ntohs(dport), dif); 269} 270 271/* Socket demux engine toys. */ 272/* What happens here is ugly; there's a pair of adjacent fields in 273 struct inet_sock; __be16 dport followed by __u16 num. We want to 274 search by pair, so we combine the keys into a single 32bit value 275 and compare with 32bit value read from &...->dport. Let's at least 276 make sure that it's not mixed with anything else... 277 On 64bit targets we combine comparisons with pair of adjacent __be32 278 fields in the same way. 279*/ 280typedef __u32 __bitwise __portpair; 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) 290typedef __u64 __bitwise __addrpair; 291#ifdef __BIG_ENDIAN 292#define INET_ADDR_COOKIE(__name, __saddr, __daddr) \ 293 const __addrpair __name = (__force __addrpair) ( \ 294 (((__force __u64)(__be32)(__saddr)) << 32) | \ 295 ((__force __u64)(__be32)(__daddr))); 296#else /* __LITTLE_ENDIAN */ 297#define INET_ADDR_COOKIE(__name, __saddr, __daddr) \ 298 const __addrpair __name = (__force __addrpair) ( \ 299 (((__force __u64)(__be32)(__daddr)) << 32) | \ 300 ((__force __u64)(__be32)(__saddr))); 301#endif /* __BIG_ENDIAN */ 302#define INET_MATCH(__sk, __net, __hash, __cookie, __saddr, __daddr, __ports, __dif)\ 303 (((__sk)->sk_hash == (__hash)) && net_eq(sock_net(__sk), (__net)) && \ 304 ((*((__addrpair *)&(inet_sk(__sk)->inet_daddr))) == (__cookie)) && \ 305 ((*((__portpair *)&(inet_sk(__sk)->inet_dport))) == (__ports)) && \ 306 (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) 307#define INET_TW_MATCH(__sk, __net, __hash, __cookie, __saddr, __daddr, __ports, __dif)\ 308 (((__sk)->sk_hash == (__hash)) && net_eq(sock_net(__sk), (__net)) && \ 309 ((*((__addrpair *)&(inet_twsk(__sk)->tw_daddr))) == (__cookie)) && \ 310 ((*((__portpair *)&(inet_twsk(__sk)->tw_dport))) == (__ports)) && \ 311 (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) 312#else /* 32-bit arch */ 313#define INET_ADDR_COOKIE(__name, __saddr, __daddr) 314#define INET_MATCH(__sk, __net, __hash, __cookie, __saddr, __daddr, __ports, __dif) \ 315 (((__sk)->sk_hash == (__hash)) && net_eq(sock_net(__sk), (__net)) && \ 316 (inet_sk(__sk)->inet_daddr == (__saddr)) && \ 317 (inet_sk(__sk)->inet_rcv_saddr == (__daddr)) && \ 318 ((*((__portpair *)&(inet_sk(__sk)->inet_dport))) == (__ports)) && \ 319 (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) 320#define INET_TW_MATCH(__sk, __net, __hash,__cookie, __saddr, __daddr, __ports, __dif) \ 321 (((__sk)->sk_hash == (__hash)) && net_eq(sock_net(__sk), (__net)) && \ 322 (inet_twsk(__sk)->tw_daddr == (__saddr)) && \ 323 (inet_twsk(__sk)->tw_rcv_saddr == (__daddr)) && \ 324 ((*((__portpair *)&(inet_twsk(__sk)->tw_dport))) == (__ports)) && \ 325 (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) 326#endif /* 64-bit arch */ 327 328/* 329 * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so we need 330 * not check it for lookups anymore, thanks Alexey. -DaveM 331 * 332 * Local BH must be disabled here. 333 */ 334extern struct sock * __inet_lookup_established(struct net *net, 335 struct inet_hashinfo *hashinfo, 336 const __be32 saddr, const __be16 sport, 337 const __be32 daddr, const u16 hnum, const int dif); 338 339static inline struct sock * 340 inet_lookup_established(struct net *net, struct inet_hashinfo *hashinfo, 341 const __be32 saddr, const __be16 sport, 342 const __be32 daddr, const __be16 dport, 343 const int dif) 344{ 345 return __inet_lookup_established(net, hashinfo, saddr, sport, daddr, 346 ntohs(dport), dif); 347} 348 349static inline struct sock *__inet_lookup(struct net *net, 350 struct inet_hashinfo *hashinfo, 351 const __be32 saddr, const __be16 sport, 352 const __be32 daddr, const __be16 dport, 353 const int dif) 354{ 355 u16 hnum = ntohs(dport); 356 struct sock *sk = __inet_lookup_established(net, hashinfo, 357 saddr, sport, daddr, hnum, dif); 358 359 return sk ? : __inet_lookup_listener(net, hashinfo, daddr, hnum, dif); 360} 361 362static inline struct sock *inet_lookup(struct net *net, 363 struct inet_hashinfo *hashinfo, 364 const __be32 saddr, const __be16 sport, 365 const __be32 daddr, const __be16 dport, 366 const int dif) 367{ 368 struct sock *sk; 369 370 local_bh_disable(); 371 sk = __inet_lookup(net, hashinfo, saddr, sport, daddr, dport, dif); 372 local_bh_enable(); 373 374 return sk; 375} 376 377static inline struct sock *__inet_lookup_skb(struct inet_hashinfo *hashinfo, 378 struct sk_buff *skb, 379 const __be16 sport, 380 const __be16 dport) 381{ 382 struct sock *sk; 383 const struct iphdr *iph = ip_hdr(skb); 384 385 if (unlikely(sk = skb_steal_sock(skb))) 386 return sk; 387 else 388 return __inet_lookup(dev_net(skb_dst(skb)->dev), hashinfo, 389 iph->saddr, sport, 390 iph->daddr, dport, inet_iif(skb)); 391} 392 393extern int __inet_hash_connect(struct inet_timewait_death_row *death_row, 394 struct sock *sk, 395 u32 port_offset, 396 int (*check_established)(struct inet_timewait_death_row *, 397 struct sock *, __u16, struct inet_timewait_sock **), 398 int (*hash)(struct sock *sk, struct inet_timewait_sock *twp)); 399 400extern int inet_hash_connect(struct inet_timewait_death_row *death_row, 401 struct sock *sk); 402#endif /* _INET_HASHTABLES_H */ 403