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)
102 EXPORT_SYMBOL(inet_put_port);
104 void __inet_inherit_port(struct sock *sk, struct sock *child)
106 struct inet_hashinfo *table = sk->sk_prot->h.hashinfo;
107 const int bhash = inet_bhashfn(sock_net(sk), inet_sk(child)->inet_num,
109 struct inet_bind_hashbucket *head = &table->bhash[bhash];
110 struct inet_bind_bucket *tb;
112 spin_lock(&head->lock);
113 tb = inet_csk(sk)->icsk_bind_hash;
114 sk_add_bind_node(child, &tb->owners);
115 inet_csk(child)->icsk_bind_hash = tb;
116 spin_unlock(&head->lock);
118 EXPORT_SYMBOL_GPL(__inet_inherit_port);
120 static inline int compute_score(struct sock *sk, struct net *net,
121 const unsigned short hnum, const __be32 daddr,
125 struct inet_sock *inet = inet_sk(sk);
127 if (net_eq(sock_net(sk), net) && inet->inet_num == hnum &&
128 !ipv6_only_sock(sk)) {
129 __be32 rcv_saddr = inet->inet_rcv_saddr;
130 score = sk->sk_family == PF_INET ? 1 : 0;
132 if (rcv_saddr != daddr)
136 if (sk->sk_bound_dev_if) {
137 if (sk->sk_bound_dev_if != dif)
146 * Don't inline this cruft. Here are some nice properties to exploit here. The
147 * BSD API does not allow a listening sock to specify the remote port nor the
148 * remote address for the connection. So always assume those are both
149 * wildcarded during the search since they can never be otherwise.
153 struct sock *__inet_lookup_listener(struct net *net,
154 struct inet_hashinfo *hashinfo,
155 const __be32 daddr, const unsigned short hnum,
158 struct sock *sk, *result;
159 struct hlist_nulls_node *node;
160 unsigned int hash = inet_lhashfn(net, hnum);
161 struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];
168 sk_nulls_for_each_rcu(sk, node, &ilb->head) {
169 score = compute_score(sk, net, hnum, daddr, dif);
170 if (score > hiscore) {
176 * if the nulls value we got at the end of this lookup is
177 * not the expected one, we must restart lookup.
178 * We probably met an item that was moved to another chain.
180 if (get_nulls_value(node) != hash + LISTENING_NULLS_BASE)
183 if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
185 else if (unlikely(compute_score(result, net, hnum, daddr,
194 EXPORT_SYMBOL_GPL(__inet_lookup_listener);
196 struct sock * __inet_lookup_established(struct net *net,
197 struct inet_hashinfo *hashinfo,
198 const __be32 saddr, const __be16 sport,
199 const __be32 daddr, const u16 hnum,
202 INET_ADDR_COOKIE(acookie, saddr, daddr)
203 const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
205 const struct hlist_nulls_node *node;
206 /* Optimize here for direct hit, only listening connections can
207 * have wildcards anyways.
209 unsigned int hash = inet_ehashfn(net, daddr, hnum, saddr, sport);
210 unsigned int slot = hash & hashinfo->ehash_mask;
211 struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
215 sk_nulls_for_each_rcu(sk, node, &head->chain) {
216 if (INET_MATCH(sk, net, hash, acookie,
217 saddr, daddr, ports, dif)) {
218 if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt)))
220 if (unlikely(!INET_MATCH(sk, net, hash, acookie,
221 saddr, daddr, ports, dif))) {
229 * if the nulls value we got at the end of this lookup is
230 * not the expected one, we must restart lookup.
231 * We probably met an item that was moved to another chain.
233 if (get_nulls_value(node) != slot)
237 /* Must check for a TIME_WAIT'er before going to listener hash. */
238 sk_nulls_for_each_rcu(sk, node, &head->twchain) {
239 if (INET_TW_MATCH(sk, net, hash, acookie,
240 saddr, daddr, ports, dif)) {
241 if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt))) {
245 if (unlikely(!INET_TW_MATCH(sk, net, hash, acookie,
246 saddr, daddr, ports, dif))) {
254 * if the nulls value we got at the end of this lookup is
255 * not the expected one, we must restart lookup.
256 * We probably met an item that was moved to another chain.
258 if (get_nulls_value(node) != slot)
265 EXPORT_SYMBOL_GPL(__inet_lookup_established);
267 /* called with local bh disabled */
268 static int __inet_check_established(struct inet_timewait_death_row *death_row,
269 struct sock *sk, __u16 lport,
270 struct inet_timewait_sock **twp)
272 struct inet_hashinfo *hinfo = death_row->hashinfo;
273 struct inet_sock *inet = inet_sk(sk);
274 __be32 daddr = inet->inet_rcv_saddr;
275 __be32 saddr = inet->inet_daddr;
276 int dif = sk->sk_bound_dev_if;
277 INET_ADDR_COOKIE(acookie, saddr, daddr)
278 const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
279 struct net *net = sock_net(sk);
280 unsigned int hash = inet_ehashfn(net, daddr, lport,
281 saddr, inet->inet_dport);
282 struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
283 spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
285 const struct hlist_nulls_node *node;
286 struct inet_timewait_sock *tw;
291 /* Check TIME-WAIT sockets first. */
292 sk_nulls_for_each(sk2, node, &head->twchain) {
295 if (INET_TW_MATCH(sk2, net, hash, acookie,
296 saddr, daddr, ports, dif)) {
297 if (twsk_unique(sk, sk2, twp))
305 /* And established part... */
306 sk_nulls_for_each(sk2, node, &head->chain) {
307 if (INET_MATCH(sk2, net, hash, acookie,
308 saddr, daddr, ports, dif))
313 /* Must record num and sport now. Otherwise we will see
314 * in hash table socket with a funny identity. */
315 inet->inet_num = lport;
316 inet->inet_sport = htons(lport);
318 WARN_ON(!sk_unhashed(sk));
319 __sk_nulls_add_node_rcu(sk, &head->chain);
321 twrefcnt = inet_twsk_unhash(tw);
322 NET_INC_STATS_BH(net, LINUX_MIB_TIMEWAITRECYCLED);
327 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
332 /* Silly. Should hash-dance instead... */
333 inet_twsk_deschedule(tw, death_row);
341 return -EADDRNOTAVAIL;
344 static inline u32 inet_sk_port_offset(const struct sock *sk)
346 const struct inet_sock *inet = inet_sk(sk);
347 return secure_ipv4_port_ephemeral(inet->inet_rcv_saddr,
352 int __inet_hash_nolisten(struct sock *sk, struct inet_timewait_sock *tw)
354 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
355 struct hlist_nulls_head *list;
357 struct inet_ehash_bucket *head;
360 WARN_ON(!sk_unhashed(sk));
362 sk->sk_hash = inet_sk_ehashfn(sk);
363 head = inet_ehash_bucket(hashinfo, sk->sk_hash);
365 lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
368 __sk_nulls_add_node_rcu(sk, list);
370 WARN_ON(sk->sk_hash != tw->tw_hash);
371 twrefcnt = inet_twsk_unhash(tw);
374 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
377 EXPORT_SYMBOL_GPL(__inet_hash_nolisten);
379 static void __inet_hash(struct sock *sk)
381 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
382 struct inet_listen_hashbucket *ilb;
384 if (sk->sk_state != TCP_LISTEN) {
385 __inet_hash_nolisten(sk, NULL);
389 WARN_ON(!sk_unhashed(sk));
390 ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
392 spin_lock(&ilb->lock);
393 __sk_nulls_add_node_rcu(sk, &ilb->head);
394 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
395 spin_unlock(&ilb->lock);
398 void inet_hash(struct sock *sk)
400 if (sk->sk_state != TCP_CLOSE) {
406 EXPORT_SYMBOL_GPL(inet_hash);
408 void inet_unhash(struct sock *sk)
410 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
417 if (sk->sk_state == TCP_LISTEN)
418 lock = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)].lock;
420 lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
423 done =__sk_nulls_del_node_init_rcu(sk);
425 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
426 spin_unlock_bh(lock);
428 EXPORT_SYMBOL_GPL(inet_unhash);
430 int __inet_hash_connect(struct inet_timewait_death_row *death_row,
431 struct sock *sk, u32 port_offset,
432 int (*check_established)(struct inet_timewait_death_row *,
433 struct sock *, __u16, struct inet_timewait_sock **),
434 int (*hash)(struct sock *sk, struct inet_timewait_sock *twp))
436 struct inet_hashinfo *hinfo = death_row->hashinfo;
437 const unsigned short snum = inet_sk(sk)->inet_num;
438 struct inet_bind_hashbucket *head;
439 struct inet_bind_bucket *tb;
441 struct net *net = sock_net(sk);
445 int i, remaining, low, high, port;
447 u32 offset = hint + port_offset;
448 struct hlist_node *node;
449 struct inet_timewait_sock *tw = NULL;
451 inet_get_local_port_range(&low, &high);
452 remaining = (high - low) + 1;
455 for (i = 1; i <= remaining; i++) {
456 port = low + (i + offset) % remaining;
457 if (inet_is_reserved_local_port(port))
459 head = &hinfo->bhash[inet_bhashfn(net, port,
461 spin_lock(&head->lock);
463 /* Does not bother with rcv_saddr checks,
464 * because the established check is already
467 inet_bind_bucket_for_each(tb, node, &head->chain) {
468 if (net_eq(ib_net(tb), net) &&
470 if (tb->fastreuse >= 0)
472 WARN_ON(hlist_empty(&tb->owners));
473 if (!check_established(death_row, sk,
480 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
483 spin_unlock(&head->lock);
490 spin_unlock(&head->lock);
494 return -EADDRNOTAVAIL;
499 /* Head lock still held and bh's disabled */
500 inet_bind_hash(sk, tb, port);
501 if (sk_unhashed(sk)) {
502 inet_sk(sk)->inet_sport = htons(port);
503 twrefcnt += hash(sk, tw);
506 twrefcnt += inet_twsk_bind_unhash(tw, hinfo);
507 spin_unlock(&head->lock);
510 inet_twsk_deschedule(tw, death_row);
521 head = &hinfo->bhash[inet_bhashfn(net, snum, hinfo->bhash_size)];
522 tb = inet_csk(sk)->icsk_bind_hash;
523 spin_lock_bh(&head->lock);
524 if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
526 spin_unlock_bh(&head->lock);
529 spin_unlock(&head->lock);
530 /* No definite answer... Walk to established hash table */
531 ret = check_established(death_row, sk, snum, NULL);
539 * Bind a port for a connect operation and hash it.
541 int inet_hash_connect(struct inet_timewait_death_row *death_row,
544 return __inet_hash_connect(death_row, sk, inet_sk_port_offset(sk),
545 __inet_check_established, __inet_hash_nolisten);
547 EXPORT_SYMBOL_GPL(inet_hash_connect);
549 void inet_hashinfo_init(struct inet_hashinfo *h)
553 atomic_set(&h->bsockets, 0);
554 for (i = 0; i < INET_LHTABLE_SIZE; i++) {
555 spin_lock_init(&h->listening_hash[i].lock);
556 INIT_HLIST_NULLS_HEAD(&h->listening_hash[i].head,
557 i + LISTENING_NULLS_BASE);
560 EXPORT_SYMBOL_GPL(inet_hashinfo_init);