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 int __inet_inherit_port(struct sock *sk, struct sock *child)
106 struct inet_hashinfo *table = sk->sk_prot->h.hashinfo;
107 unsigned short port = inet_sk(child)->inet_num;
108 const int bhash = inet_bhashfn(sock_net(sk), port,
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 if (tb->port != port) {
116 /* NOTE: using tproxy and redirecting skbs to a proxy
117 * on a different listener port breaks the assumption
118 * that the listener socket's icsk_bind_hash is the same
119 * as that of the child socket. We have to look up or
120 * create a new bind bucket for the child here. */
121 struct hlist_node *node;
122 inet_bind_bucket_for_each(tb, node, &head->chain) {
123 if (net_eq(ib_net(tb), sock_net(sk)) &&
128 tb = inet_bind_bucket_create(table->bind_bucket_cachep,
129 sock_net(sk), head, port);
131 spin_unlock(&head->lock);
136 inet_bind_hash(child, tb, port);
137 spin_unlock(&head->lock);
141 EXPORT_SYMBOL_GPL(__inet_inherit_port);
143 static inline int compute_score(struct sock *sk, struct net *net,
144 const unsigned short hnum, const __be32 daddr,
148 struct inet_sock *inet = inet_sk(sk);
150 if (net_eq(sock_net(sk), net) && inet->inet_num == hnum &&
151 !ipv6_only_sock(sk)) {
152 __be32 rcv_saddr = inet->inet_rcv_saddr;
153 score = sk->sk_family == PF_INET ? 1 : 0;
155 if (rcv_saddr != daddr)
159 if (sk->sk_bound_dev_if) {
160 if (sk->sk_bound_dev_if != dif)
169 * Don't inline this cruft. Here are some nice properties to exploit here. The
170 * BSD API does not allow a listening sock to specify the remote port nor the
171 * remote address for the connection. So always assume those are both
172 * wildcarded during the search since they can never be otherwise.
176 struct sock *__inet_lookup_listener(struct net *net,
177 struct inet_hashinfo *hashinfo,
178 const __be32 daddr, const unsigned short hnum,
181 struct sock *sk, *result;
182 struct hlist_nulls_node *node;
183 unsigned int hash = inet_lhashfn(net, hnum);
184 struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];
191 sk_nulls_for_each_rcu(sk, node, &ilb->head) {
192 score = compute_score(sk, net, hnum, daddr, dif);
193 if (score > hiscore) {
199 * if the nulls value we got at the end of this lookup is
200 * not the expected one, we must restart lookup.
201 * We probably met an item that was moved to another chain.
203 if (get_nulls_value(node) != hash + LISTENING_NULLS_BASE)
206 if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
208 else if (unlikely(compute_score(result, net, hnum, daddr,
217 EXPORT_SYMBOL_GPL(__inet_lookup_listener);
219 struct sock * __inet_lookup_established(struct net *net,
220 struct inet_hashinfo *hashinfo,
221 const __be32 saddr, const __be16 sport,
222 const __be32 daddr, const u16 hnum,
225 INET_ADDR_COOKIE(acookie, saddr, daddr)
226 const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
228 const struct hlist_nulls_node *node;
229 /* Optimize here for direct hit, only listening connections can
230 * have wildcards anyways.
232 unsigned int hash = inet_ehashfn(net, daddr, hnum, saddr, sport);
233 unsigned int slot = hash & hashinfo->ehash_mask;
234 struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
238 sk_nulls_for_each_rcu(sk, node, &head->chain) {
239 if (INET_MATCH(sk, net, hash, acookie,
240 saddr, daddr, ports, dif)) {
241 if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt)))
243 if (unlikely(!INET_MATCH(sk, net, hash, acookie,
244 saddr, daddr, ports, dif))) {
252 * if the nulls value we got at the end of this lookup is
253 * not the expected one, we must restart lookup.
254 * We probably met an item that was moved to another chain.
256 if (get_nulls_value(node) != slot)
260 /* Must check for a TIME_WAIT'er before going to listener hash. */
261 sk_nulls_for_each_rcu(sk, node, &head->twchain) {
262 if (INET_TW_MATCH(sk, net, hash, acookie,
263 saddr, daddr, ports, dif)) {
264 if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt))) {
268 if (unlikely(!INET_TW_MATCH(sk, net, hash, acookie,
269 saddr, daddr, ports, dif))) {
277 * if the nulls value we got at the end of this lookup is
278 * not the expected one, we must restart lookup.
279 * We probably met an item that was moved to another chain.
281 if (get_nulls_value(node) != slot)
288 EXPORT_SYMBOL_GPL(__inet_lookup_established);
290 /* called with local bh disabled */
291 static int __inet_check_established(struct inet_timewait_death_row *death_row,
292 struct sock *sk, __u16 lport,
293 struct inet_timewait_sock **twp)
295 struct inet_hashinfo *hinfo = death_row->hashinfo;
296 struct inet_sock *inet = inet_sk(sk);
297 __be32 daddr = inet->inet_rcv_saddr;
298 __be32 saddr = inet->inet_daddr;
299 int dif = sk->sk_bound_dev_if;
300 INET_ADDR_COOKIE(acookie, saddr, daddr)
301 const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
302 struct net *net = sock_net(sk);
303 unsigned int hash = inet_ehashfn(net, daddr, lport,
304 saddr, inet->inet_dport);
305 struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
306 spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
308 const struct hlist_nulls_node *node;
309 struct inet_timewait_sock *tw;
314 /* Check TIME-WAIT sockets first. */
315 sk_nulls_for_each(sk2, node, &head->twchain) {
318 if (INET_TW_MATCH(sk2, net, hash, acookie,
319 saddr, daddr, ports, dif)) {
320 if (twsk_unique(sk, sk2, twp))
328 /* And established part... */
329 sk_nulls_for_each(sk2, node, &head->chain) {
330 if (INET_MATCH(sk2, net, hash, acookie,
331 saddr, daddr, ports, dif))
336 /* Must record num and sport now. Otherwise we will see
337 * in hash table socket with a funny identity. */
338 inet->inet_num = lport;
339 inet->inet_sport = htons(lport);
341 WARN_ON(!sk_unhashed(sk));
342 __sk_nulls_add_node_rcu(sk, &head->chain);
344 twrefcnt = inet_twsk_unhash(tw);
345 NET_INC_STATS_BH(net, LINUX_MIB_TIMEWAITRECYCLED);
350 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
355 /* Silly. Should hash-dance instead... */
356 inet_twsk_deschedule(tw, death_row);
364 return -EADDRNOTAVAIL;
367 static inline u32 inet_sk_port_offset(const struct sock *sk)
369 const struct inet_sock *inet = inet_sk(sk);
370 return secure_ipv4_port_ephemeral(inet->inet_rcv_saddr,
375 int __inet_hash_nolisten(struct sock *sk, struct inet_timewait_sock *tw)
377 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
378 struct hlist_nulls_head *list;
380 struct inet_ehash_bucket *head;
383 WARN_ON(!sk_unhashed(sk));
385 sk->sk_hash = inet_sk_ehashfn(sk);
386 head = inet_ehash_bucket(hashinfo, sk->sk_hash);
388 lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
391 __sk_nulls_add_node_rcu(sk, list);
393 WARN_ON(sk->sk_hash != tw->tw_hash);
394 twrefcnt = inet_twsk_unhash(tw);
397 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
400 EXPORT_SYMBOL_GPL(__inet_hash_nolisten);
402 static void __inet_hash(struct sock *sk)
404 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
405 struct inet_listen_hashbucket *ilb;
407 if (sk->sk_state != TCP_LISTEN) {
408 __inet_hash_nolisten(sk, NULL);
412 WARN_ON(!sk_unhashed(sk));
413 ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
415 spin_lock(&ilb->lock);
416 __sk_nulls_add_node_rcu(sk, &ilb->head);
417 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
418 spin_unlock(&ilb->lock);
421 void inet_hash(struct sock *sk)
423 if (sk->sk_state != TCP_CLOSE) {
429 EXPORT_SYMBOL_GPL(inet_hash);
431 void inet_unhash(struct sock *sk)
433 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
440 if (sk->sk_state == TCP_LISTEN)
441 lock = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)].lock;
443 lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
446 done =__sk_nulls_del_node_init_rcu(sk);
448 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
449 spin_unlock_bh(lock);
451 EXPORT_SYMBOL_GPL(inet_unhash);
453 int __inet_hash_connect(struct inet_timewait_death_row *death_row,
454 struct sock *sk, u32 port_offset,
455 int (*check_established)(struct inet_timewait_death_row *,
456 struct sock *, __u16, struct inet_timewait_sock **),
457 int (*hash)(struct sock *sk, struct inet_timewait_sock *twp))
459 struct inet_hashinfo *hinfo = death_row->hashinfo;
460 const unsigned short snum = inet_sk(sk)->inet_num;
461 struct inet_bind_hashbucket *head;
462 struct inet_bind_bucket *tb;
464 struct net *net = sock_net(sk);
468 int i, remaining, low, high, port;
470 u32 offset = hint + port_offset;
471 struct hlist_node *node;
472 struct inet_timewait_sock *tw = NULL;
474 inet_get_local_port_range(&low, &high);
475 remaining = (high - low) + 1;
478 for (i = 1; i <= remaining; i++) {
479 port = low + (i + offset) % remaining;
480 if (inet_is_reserved_local_port(port))
482 head = &hinfo->bhash[inet_bhashfn(net, port,
484 spin_lock(&head->lock);
486 /* Does not bother with rcv_saddr checks,
487 * because the established check is already
490 inet_bind_bucket_for_each(tb, node, &head->chain) {
491 if (net_eq(ib_net(tb), net) &&
493 if (tb->fastreuse >= 0)
495 WARN_ON(hlist_empty(&tb->owners));
496 if (!check_established(death_row, sk,
503 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
506 spin_unlock(&head->lock);
513 spin_unlock(&head->lock);
517 return -EADDRNOTAVAIL;
522 /* Head lock still held and bh's disabled */
523 inet_bind_hash(sk, tb, port);
524 if (sk_unhashed(sk)) {
525 inet_sk(sk)->inet_sport = htons(port);
526 twrefcnt += hash(sk, tw);
529 twrefcnt += inet_twsk_bind_unhash(tw, hinfo);
530 spin_unlock(&head->lock);
533 inet_twsk_deschedule(tw, death_row);
544 head = &hinfo->bhash[inet_bhashfn(net, snum, hinfo->bhash_size)];
545 tb = inet_csk(sk)->icsk_bind_hash;
546 spin_lock_bh(&head->lock);
547 if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
549 spin_unlock_bh(&head->lock);
552 spin_unlock(&head->lock);
553 /* No definite answer... Walk to established hash table */
554 ret = check_established(death_row, sk, snum, NULL);
562 * Bind a port for a connect operation and hash it.
564 int inet_hash_connect(struct inet_timewait_death_row *death_row,
567 return __inet_hash_connect(death_row, sk, inet_sk_port_offset(sk),
568 __inet_check_established, __inet_hash_nolisten);
570 EXPORT_SYMBOL_GPL(inet_hash_connect);
572 void inet_hashinfo_init(struct inet_hashinfo *h)
576 atomic_set(&h->bsockets, 0);
577 for (i = 0; i < INET_LHTABLE_SIZE; i++) {
578 spin_lock_init(&h->listening_hash[i].lock);
579 INIT_HLIST_NULLS_HEAD(&h->listening_hash[i].head,
580 i + LISTENING_NULLS_BASE);
583 EXPORT_SYMBOL_GPL(inet_hashinfo_init);