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.
6 * Generic INET transport hashtables
8 * Authors: Lotsa people, from code originally in tcp
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
16 #include <linux/module.h>
17 #include <linux/random.h>
18 #include <linux/sched.h>
19 #include <linux/slab.h>
20 #include <linux/wait.h>
22 #include <net/inet_connection_sock.h>
23 #include <net/inet_hashtables.h>
27 * Allocate and initialize a new local port bind bucket.
28 * The bindhash mutex for snum's hash chain must be held here.
30 struct inet_bind_bucket *inet_bind_bucket_create(struct kmem_cache *cachep,
32 struct inet_bind_hashbucket *head,
33 const unsigned short snum)
35 struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, GFP_ATOMIC);
38 write_pnet(&tb->ib_net, hold_net(net));
42 INIT_HLIST_HEAD(&tb->owners);
43 hlist_add_head(&tb->node, &head->chain);
49 * Caller must hold hashbucket lock for this tb with local BH disabled
51 void inet_bind_bucket_destroy(struct kmem_cache *cachep, struct inet_bind_bucket *tb)
53 if (hlist_empty(&tb->owners)) {
54 __hlist_del(&tb->node);
55 release_net(ib_net(tb));
56 kmem_cache_free(cachep, tb);
60 void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
61 const unsigned short snum)
63 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
65 atomic_inc(&hashinfo->bsockets);
67 inet_sk(sk)->inet_num = snum;
68 sk_add_bind_node(sk, &tb->owners);
70 inet_csk(sk)->icsk_bind_hash = tb;
74 * Get rid of any references to a local port held by the given sock.
76 static void __inet_put_port(struct sock *sk)
78 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
79 const int bhash = inet_bhashfn(sock_net(sk), inet_sk(sk)->inet_num,
80 hashinfo->bhash_size);
81 struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash];
82 struct inet_bind_bucket *tb;
84 atomic_dec(&hashinfo->bsockets);
86 spin_lock(&head->lock);
87 tb = inet_csk(sk)->icsk_bind_hash;
88 __sk_del_bind_node(sk);
90 inet_csk(sk)->icsk_bind_hash = NULL;
91 inet_sk(sk)->inet_num = 0;
92 inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);
93 spin_unlock(&head->lock);
96 void inet_put_port(struct sock *sk)
103 EXPORT_SYMBOL(inet_put_port);
105 void __inet_inherit_port(struct sock *sk, struct sock *child)
107 struct inet_hashinfo *table = sk->sk_prot->h.hashinfo;
108 const int bhash = inet_bhashfn(sock_net(sk), inet_sk(child)->inet_num,
110 struct inet_bind_hashbucket *head = &table->bhash[bhash];
111 struct inet_bind_bucket *tb;
113 spin_lock(&head->lock);
114 tb = inet_csk(sk)->icsk_bind_hash;
115 sk_add_bind_node(child, &tb->owners);
116 inet_csk(child)->icsk_bind_hash = tb;
117 spin_unlock(&head->lock);
120 EXPORT_SYMBOL_GPL(__inet_inherit_port);
122 static inline int compute_score(struct sock *sk, struct net *net,
123 const unsigned short hnum, const __be32 daddr,
127 struct inet_sock *inet = inet_sk(sk);
129 if (net_eq(sock_net(sk), net) && inet->inet_num == hnum &&
130 !ipv6_only_sock(sk)) {
131 __be32 rcv_saddr = inet->inet_rcv_saddr;
132 score = sk->sk_family == PF_INET ? 1 : 0;
134 if (rcv_saddr != daddr)
138 if (sk->sk_bound_dev_if) {
139 if (sk->sk_bound_dev_if != dif)
148 * Don't inline this cruft. Here are some nice properties to exploit here. The
149 * BSD API does not allow a listening sock to specify the remote port nor the
150 * remote address for the connection. So always assume those are both
151 * wildcarded during the search since they can never be otherwise.
155 struct sock *__inet_lookup_listener(struct net *net,
156 struct inet_hashinfo *hashinfo,
157 const __be32 daddr, const unsigned short hnum,
160 struct sock *sk, *result;
161 struct hlist_nulls_node *node;
162 unsigned int hash = inet_lhashfn(net, hnum);
163 struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];
170 sk_nulls_for_each_rcu(sk, node, &ilb->head) {
171 score = compute_score(sk, net, hnum, daddr, dif);
172 if (score > hiscore) {
178 * if the nulls value we got at the end of this lookup is
179 * not the expected one, we must restart lookup.
180 * We probably met an item that was moved to another chain.
182 if (get_nulls_value(node) != hash + LISTENING_NULLS_BASE)
185 if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
187 else if (unlikely(compute_score(result, net, hnum, daddr,
196 EXPORT_SYMBOL_GPL(__inet_lookup_listener);
198 struct sock * __inet_lookup_established(struct net *net,
199 struct inet_hashinfo *hashinfo,
200 const __be32 saddr, const __be16 sport,
201 const __be32 daddr, const u16 hnum,
204 INET_ADDR_COOKIE(acookie, saddr, daddr)
205 const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
207 const struct hlist_nulls_node *node;
208 /* Optimize here for direct hit, only listening connections can
209 * have wildcards anyways.
211 unsigned int hash = inet_ehashfn(net, daddr, hnum, saddr, sport);
212 unsigned int slot = hash & hashinfo->ehash_mask;
213 struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
217 sk_nulls_for_each_rcu(sk, node, &head->chain) {
218 if (INET_MATCH(sk, net, hash, acookie,
219 saddr, daddr, ports, dif)) {
220 if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt)))
222 if (unlikely(!INET_MATCH(sk, net, hash, acookie,
223 saddr, daddr, ports, dif))) {
231 * if the nulls value we got at the end of this lookup is
232 * not the expected one, we must restart lookup.
233 * We probably met an item that was moved to another chain.
235 if (get_nulls_value(node) != slot)
239 /* Must check for a TIME_WAIT'er before going to listener hash. */
240 sk_nulls_for_each_rcu(sk, node, &head->twchain) {
241 if (INET_TW_MATCH(sk, net, hash, acookie,
242 saddr, daddr, ports, dif)) {
243 if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt))) {
247 if (unlikely(!INET_TW_MATCH(sk, net, hash, acookie,
248 saddr, daddr, ports, dif))) {
256 * if the nulls value we got at the end of this lookup is
257 * not the expected one, we must restart lookup.
258 * We probably met an item that was moved to another chain.
260 if (get_nulls_value(node) != slot)
267 EXPORT_SYMBOL_GPL(__inet_lookup_established);
269 /* called with local bh disabled */
270 static int __inet_check_established(struct inet_timewait_death_row *death_row,
271 struct sock *sk, __u16 lport,
272 struct inet_timewait_sock **twp)
274 struct inet_hashinfo *hinfo = death_row->hashinfo;
275 struct inet_sock *inet = inet_sk(sk);
276 __be32 daddr = inet->inet_rcv_saddr;
277 __be32 saddr = inet->inet_daddr;
278 int dif = sk->sk_bound_dev_if;
279 INET_ADDR_COOKIE(acookie, saddr, daddr)
280 const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
281 struct net *net = sock_net(sk);
282 unsigned int hash = inet_ehashfn(net, daddr, lport,
283 saddr, inet->inet_dport);
284 struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
285 spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
287 const struct hlist_nulls_node *node;
288 struct inet_timewait_sock *tw;
293 /* Check TIME-WAIT sockets first. */
294 sk_nulls_for_each(sk2, node, &head->twchain) {
297 if (INET_TW_MATCH(sk2, net, hash, acookie,
298 saddr, daddr, ports, dif)) {
299 if (twsk_unique(sk, sk2, twp))
307 /* And established part... */
308 sk_nulls_for_each(sk2, node, &head->chain) {
309 if (INET_MATCH(sk2, net, hash, acookie,
310 saddr, daddr, ports, dif))
315 /* Must record num and sport now. Otherwise we will see
316 * in hash table socket with a funny identity. */
317 inet->inet_num = lport;
318 inet->inet_sport = htons(lport);
320 WARN_ON(!sk_unhashed(sk));
321 __sk_nulls_add_node_rcu(sk, &head->chain);
323 twrefcnt = inet_twsk_unhash(tw);
324 NET_INC_STATS_BH(net, LINUX_MIB_TIMEWAITRECYCLED);
329 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
334 /* Silly. Should hash-dance instead... */
335 inet_twsk_deschedule(tw, death_row);
343 return -EADDRNOTAVAIL;
346 static inline u32 inet_sk_port_offset(const struct sock *sk)
348 const struct inet_sock *inet = inet_sk(sk);
349 return secure_ipv4_port_ephemeral(inet->inet_rcv_saddr,
354 void __inet_hash_nolisten(struct sock *sk)
356 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
357 struct hlist_nulls_head *list;
359 struct inet_ehash_bucket *head;
361 WARN_ON(!sk_unhashed(sk));
363 sk->sk_hash = inet_sk_ehashfn(sk);
364 head = inet_ehash_bucket(hashinfo, sk->sk_hash);
366 lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
369 __sk_nulls_add_node_rcu(sk, list);
371 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
373 EXPORT_SYMBOL_GPL(__inet_hash_nolisten);
375 static void __inet_hash(struct sock *sk)
377 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
378 struct inet_listen_hashbucket *ilb;
380 if (sk->sk_state != TCP_LISTEN) {
381 __inet_hash_nolisten(sk);
385 WARN_ON(!sk_unhashed(sk));
386 ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
388 spin_lock(&ilb->lock);
389 __sk_nulls_add_node_rcu(sk, &ilb->head);
390 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
391 spin_unlock(&ilb->lock);
394 void inet_hash(struct sock *sk)
396 if (sk->sk_state != TCP_CLOSE) {
402 EXPORT_SYMBOL_GPL(inet_hash);
404 void inet_unhash(struct sock *sk)
406 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
413 if (sk->sk_state == TCP_LISTEN)
414 lock = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)].lock;
416 lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
419 done =__sk_nulls_del_node_init_rcu(sk);
421 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
422 spin_unlock_bh(lock);
424 EXPORT_SYMBOL_GPL(inet_unhash);
426 int __inet_hash_connect(struct inet_timewait_death_row *death_row,
427 struct sock *sk, u32 port_offset,
428 int (*check_established)(struct inet_timewait_death_row *,
429 struct sock *, __u16, struct inet_timewait_sock **),
430 void (*hash)(struct sock *sk))
432 struct inet_hashinfo *hinfo = death_row->hashinfo;
433 const unsigned short snum = inet_sk(sk)->inet_num;
434 struct inet_bind_hashbucket *head;
435 struct inet_bind_bucket *tb;
437 struct net *net = sock_net(sk);
440 int i, remaining, low, high, port;
442 u32 offset = hint + port_offset;
443 struct hlist_node *node;
444 struct inet_timewait_sock *tw = NULL;
446 inet_get_local_port_range(&low, &high);
447 remaining = (high - low) + 1;
450 for (i = 1; i <= remaining; i++) {
451 port = low + (i + offset) % remaining;
452 head = &hinfo->bhash[inet_bhashfn(net, port,
454 spin_lock(&head->lock);
456 /* Does not bother with rcv_saddr checks,
457 * because the established check is already
460 inet_bind_bucket_for_each(tb, node, &head->chain) {
461 if (net_eq(ib_net(tb), net) &&
463 if (tb->fastreuse >= 0)
465 WARN_ON(hlist_empty(&tb->owners));
466 if (!check_established(death_row, sk,
473 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
476 spin_unlock(&head->lock);
483 spin_unlock(&head->lock);
487 return -EADDRNOTAVAIL;
492 /* Head lock still held and bh's disabled */
493 inet_bind_hash(sk, tb, port);
494 if (sk_unhashed(sk)) {
495 inet_sk(sk)->inet_sport = htons(port);
498 spin_unlock(&head->lock);
501 inet_twsk_deschedule(tw, death_row);
509 head = &hinfo->bhash[inet_bhashfn(net, snum, hinfo->bhash_size)];
510 tb = inet_csk(sk)->icsk_bind_hash;
511 spin_lock_bh(&head->lock);
512 if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
514 spin_unlock_bh(&head->lock);
517 spin_unlock(&head->lock);
518 /* No definite answer... Walk to established hash table */
519 ret = check_established(death_row, sk, snum, NULL);
527 * Bind a port for a connect operation and hash it.
529 int inet_hash_connect(struct inet_timewait_death_row *death_row,
532 return __inet_hash_connect(death_row, sk, inet_sk_port_offset(sk),
533 __inet_check_established, __inet_hash_nolisten);
536 EXPORT_SYMBOL_GPL(inet_hash_connect);
538 void inet_hashinfo_init(struct inet_hashinfo *h)
542 atomic_set(&h->bsockets, 0);
543 for (i = 0; i < INET_LHTABLE_SIZE; i++) {
544 spin_lock_init(&h->listening_hash[i].lock);
545 INIT_HLIST_NULLS_HEAD(&h->listening_hash[i].head,
546 i + LISTENING_NULLS_BASE);
550 EXPORT_SYMBOL_GPL(inet_hashinfo_init);