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>
24 #include <net/secure_seq.h>
28 * Allocate and initialize a new local port bind bucket.
29 * The bindhash mutex for snum's hash chain must be held here.
31 struct inet_bind_bucket *inet_bind_bucket_create(struct kmem_cache *cachep,
33 struct inet_bind_hashbucket *head,
34 const unsigned short snum)
36 struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, GFP_ATOMIC);
39 write_pnet(&tb->ib_net, hold_net(net));
43 INIT_HLIST_HEAD(&tb->owners);
44 hlist_add_head(&tb->node, &head->chain);
50 * Caller must hold hashbucket lock for this tb with local BH disabled
52 void inet_bind_bucket_destroy(struct kmem_cache *cachep, struct inet_bind_bucket *tb)
54 if (hlist_empty(&tb->owners)) {
55 __hlist_del(&tb->node);
56 release_net(ib_net(tb));
57 kmem_cache_free(cachep, tb);
61 void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
62 const unsigned short snum)
64 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
66 atomic_inc(&hashinfo->bsockets);
68 inet_sk(sk)->inet_num = snum;
69 sk_add_bind_node(sk, &tb->owners);
71 inet_csk(sk)->icsk_bind_hash = tb;
75 * Get rid of any references to a local port held by the given sock.
77 static void __inet_put_port(struct sock *sk)
79 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
80 const int bhash = inet_bhashfn(sock_net(sk), inet_sk(sk)->inet_num,
81 hashinfo->bhash_size);
82 struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash];
83 struct inet_bind_bucket *tb;
85 atomic_dec(&hashinfo->bsockets);
87 spin_lock(&head->lock);
88 tb = inet_csk(sk)->icsk_bind_hash;
89 __sk_del_bind_node(sk);
91 inet_csk(sk)->icsk_bind_hash = NULL;
92 inet_sk(sk)->inet_num = 0;
93 inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);
94 spin_unlock(&head->lock);
97 void inet_put_port(struct sock *sk)
103 EXPORT_SYMBOL(inet_put_port);
105 int __inet_inherit_port(struct sock *sk, struct sock *child)
107 struct inet_hashinfo *table = sk->sk_prot->h.hashinfo;
108 unsigned short port = inet_sk(child)->inet_num;
109 const int bhash = inet_bhashfn(sock_net(sk), port,
111 struct inet_bind_hashbucket *head = &table->bhash[bhash];
112 struct inet_bind_bucket *tb;
114 spin_lock(&head->lock);
115 tb = inet_csk(sk)->icsk_bind_hash;
116 if (tb->port != port) {
117 /* NOTE: using tproxy and redirecting skbs to a proxy
118 * on a different listener port breaks the assumption
119 * that the listener socket's icsk_bind_hash is the same
120 * as that of the child socket. We have to look up or
121 * create a new bind bucket for the child here. */
122 struct hlist_node *node;
123 inet_bind_bucket_for_each(tb, node, &head->chain) {
124 if (net_eq(ib_net(tb), sock_net(sk)) &&
129 tb = inet_bind_bucket_create(table->bind_bucket_cachep,
130 sock_net(sk), head, port);
132 spin_unlock(&head->lock);
137 inet_bind_hash(child, tb, port);
138 spin_unlock(&head->lock);
142 EXPORT_SYMBOL_GPL(__inet_inherit_port);
144 static inline int compute_score(struct sock *sk, struct net *net,
145 const unsigned short hnum, const __be32 daddr,
149 struct inet_sock *inet = inet_sk(sk);
151 if (net_eq(sock_net(sk), net) && inet->inet_num == hnum &&
152 !ipv6_only_sock(sk)) {
153 __be32 rcv_saddr = inet->inet_rcv_saddr;
154 score = sk->sk_family == PF_INET ? 1 : 0;
156 if (rcv_saddr != daddr)
160 if (sk->sk_bound_dev_if) {
161 if (sk->sk_bound_dev_if != dif)
170 * Don't inline this cruft. Here are some nice properties to exploit here. The
171 * BSD API does not allow a listening sock to specify the remote port nor the
172 * remote address for the connection. So always assume those are both
173 * wildcarded during the search since they can never be otherwise.
177 struct sock *__inet_lookup_listener(struct net *net,
178 struct inet_hashinfo *hashinfo,
179 const __be32 daddr, const unsigned short hnum,
182 struct sock *sk, *result;
183 struct hlist_nulls_node *node;
184 unsigned int hash = inet_lhashfn(net, hnum);
185 struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];
192 sk_nulls_for_each_rcu(sk, node, &ilb->head) {
193 score = compute_score(sk, net, hnum, daddr, dif);
194 if (score > hiscore) {
200 * if the nulls value we got at the end of this lookup is
201 * not the expected one, we must restart lookup.
202 * We probably met an item that was moved to another chain.
204 if (get_nulls_value(node) != hash + LISTENING_NULLS_BASE)
207 if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
209 else if (unlikely(compute_score(result, net, hnum, daddr,
218 EXPORT_SYMBOL_GPL(__inet_lookup_listener);
220 struct sock * __inet_lookup_established(struct net *net,
221 struct inet_hashinfo *hashinfo,
222 const __be32 saddr, const __be16 sport,
223 const __be32 daddr, const u16 hnum,
226 INET_ADDR_COOKIE(acookie, saddr, daddr)
227 const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
229 const struct hlist_nulls_node *node;
230 /* Optimize here for direct hit, only listening connections can
231 * have wildcards anyways.
233 unsigned int hash = inet_ehashfn(net, daddr, hnum, saddr, sport);
234 unsigned int slot = hash & hashinfo->ehash_mask;
235 struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
239 sk_nulls_for_each_rcu(sk, node, &head->chain) {
240 if (INET_MATCH(sk, net, hash, acookie,
241 saddr, daddr, ports, dif)) {
242 if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt)))
244 if (unlikely(!INET_MATCH(sk, net, hash, acookie,
245 saddr, daddr, ports, dif))) {
253 * if the nulls value we got at the end of this lookup is
254 * not the expected one, we must restart lookup.
255 * We probably met an item that was moved to another chain.
257 if (get_nulls_value(node) != slot)
261 /* Must check for a TIME_WAIT'er before going to listener hash. */
262 sk_nulls_for_each_rcu(sk, node, &head->twchain) {
263 if (INET_TW_MATCH(sk, net, hash, acookie,
264 saddr, daddr, ports, dif)) {
265 if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt))) {
269 if (unlikely(!INET_TW_MATCH(sk, net, hash, acookie,
270 saddr, daddr, ports, dif))) {
278 * if the nulls value we got at the end of this lookup is
279 * not the expected one, we must restart lookup.
280 * We probably met an item that was moved to another chain.
282 if (get_nulls_value(node) != slot)
289 EXPORT_SYMBOL_GPL(__inet_lookup_established);
291 /* called with local bh disabled */
292 static int __inet_check_established(struct inet_timewait_death_row *death_row,
293 struct sock *sk, __u16 lport,
294 struct inet_timewait_sock **twp)
296 struct inet_hashinfo *hinfo = death_row->hashinfo;
297 struct inet_sock *inet = inet_sk(sk);
298 __be32 daddr = inet->inet_rcv_saddr;
299 __be32 saddr = inet->inet_daddr;
300 int dif = sk->sk_bound_dev_if;
301 INET_ADDR_COOKIE(acookie, saddr, daddr)
302 const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
303 struct net *net = sock_net(sk);
304 unsigned int hash = inet_ehashfn(net, daddr, lport,
305 saddr, inet->inet_dport);
306 struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
307 spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
309 const struct hlist_nulls_node *node;
310 struct inet_timewait_sock *tw;
315 /* Check TIME-WAIT sockets first. */
316 sk_nulls_for_each(sk2, node, &head->twchain) {
319 if (INET_TW_MATCH(sk2, net, hash, acookie,
320 saddr, daddr, ports, dif)) {
321 if (twsk_unique(sk, sk2, twp))
329 /* And established part... */
330 sk_nulls_for_each(sk2, node, &head->chain) {
331 if (INET_MATCH(sk2, net, hash, acookie,
332 saddr, daddr, ports, dif))
337 /* Must record num and sport now. Otherwise we will see
338 * in hash table socket with a funny identity. */
339 inet->inet_num = lport;
340 inet->inet_sport = htons(lport);
342 WARN_ON(!sk_unhashed(sk));
343 __sk_nulls_add_node_rcu(sk, &head->chain);
345 twrefcnt = inet_twsk_unhash(tw);
346 NET_INC_STATS_BH(net, LINUX_MIB_TIMEWAITRECYCLED);
351 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
356 /* Silly. Should hash-dance instead... */
357 inet_twsk_deschedule(tw, death_row);
365 return -EADDRNOTAVAIL;
368 static inline u32 inet_sk_port_offset(const struct sock *sk)
370 const struct inet_sock *inet = inet_sk(sk);
371 return secure_ipv4_port_ephemeral(inet->inet_rcv_saddr,
376 int __inet_hash_nolisten(struct sock *sk, struct inet_timewait_sock *tw)
378 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
379 struct hlist_nulls_head *list;
381 struct inet_ehash_bucket *head;
384 WARN_ON(!sk_unhashed(sk));
386 sk->sk_hash = inet_sk_ehashfn(sk);
387 head = inet_ehash_bucket(hashinfo, sk->sk_hash);
389 lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
392 __sk_nulls_add_node_rcu(sk, list);
394 WARN_ON(sk->sk_hash != tw->tw_hash);
395 twrefcnt = inet_twsk_unhash(tw);
398 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
401 EXPORT_SYMBOL_GPL(__inet_hash_nolisten);
403 static void __inet_hash(struct sock *sk)
405 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
406 struct inet_listen_hashbucket *ilb;
408 if (sk->sk_state != TCP_LISTEN) {
409 __inet_hash_nolisten(sk, NULL);
413 WARN_ON(!sk_unhashed(sk));
414 ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
416 spin_lock(&ilb->lock);
417 __sk_nulls_add_node_rcu(sk, &ilb->head);
418 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
419 spin_unlock(&ilb->lock);
422 void inet_hash(struct sock *sk)
424 if (sk->sk_state != TCP_CLOSE) {
430 EXPORT_SYMBOL_GPL(inet_hash);
432 void inet_unhash(struct sock *sk)
434 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
441 if (sk->sk_state == TCP_LISTEN)
442 lock = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)].lock;
444 lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
447 done =__sk_nulls_del_node_init_rcu(sk);
449 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
450 spin_unlock_bh(lock);
452 EXPORT_SYMBOL_GPL(inet_unhash);
454 int __inet_hash_connect(struct inet_timewait_death_row *death_row,
455 struct sock *sk, u32 port_offset,
456 int (*check_established)(struct inet_timewait_death_row *,
457 struct sock *, __u16, struct inet_timewait_sock **),
458 int (*hash)(struct sock *sk, struct inet_timewait_sock *twp))
460 struct inet_hashinfo *hinfo = death_row->hashinfo;
461 const unsigned short snum = inet_sk(sk)->inet_num;
462 struct inet_bind_hashbucket *head;
463 struct inet_bind_bucket *tb;
465 struct net *net = sock_net(sk);
469 int i, remaining, low, high, port;
471 u32 offset = hint + port_offset;
472 struct hlist_node *node;
473 struct inet_timewait_sock *tw = NULL;
475 inet_get_local_port_range(&low, &high);
476 remaining = (high - low) + 1;
479 for (i = 1; i <= remaining; i++) {
480 port = low + (i + offset) % remaining;
481 if (inet_is_reserved_local_port(port))
483 head = &hinfo->bhash[inet_bhashfn(net, port,
485 spin_lock(&head->lock);
487 /* Does not bother with rcv_saddr checks,
488 * because the established check is already
491 inet_bind_bucket_for_each(tb, node, &head->chain) {
492 if (net_eq(ib_net(tb), net) &&
494 if (tb->fastreuse >= 0)
496 WARN_ON(hlist_empty(&tb->owners));
497 if (!check_established(death_row, sk,
504 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
507 spin_unlock(&head->lock);
514 spin_unlock(&head->lock);
518 return -EADDRNOTAVAIL;
523 /* Head lock still held and bh's disabled */
524 inet_bind_hash(sk, tb, port);
525 if (sk_unhashed(sk)) {
526 inet_sk(sk)->inet_sport = htons(port);
527 twrefcnt += hash(sk, tw);
530 twrefcnt += inet_twsk_bind_unhash(tw, hinfo);
531 spin_unlock(&head->lock);
534 inet_twsk_deschedule(tw, death_row);
545 head = &hinfo->bhash[inet_bhashfn(net, snum, hinfo->bhash_size)];
546 tb = inet_csk(sk)->icsk_bind_hash;
547 spin_lock_bh(&head->lock);
548 if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
550 spin_unlock_bh(&head->lock);
553 spin_unlock(&head->lock);
554 /* No definite answer... Walk to established hash table */
555 ret = check_established(death_row, sk, snum, NULL);
563 * Bind a port for a connect operation and hash it.
565 int inet_hash_connect(struct inet_timewait_death_row *death_row,
568 return __inet_hash_connect(death_row, sk, inet_sk_port_offset(sk),
569 __inet_check_established, __inet_hash_nolisten);
571 EXPORT_SYMBOL_GPL(inet_hash_connect);
573 void inet_hashinfo_init(struct inet_hashinfo *h)
577 atomic_set(&h->bsockets, 0);
578 for (i = 0; i < INET_LHTABLE_SIZE; i++) {
579 spin_lock_init(&h->listening_hash[i].lock);
580 INIT_HLIST_NULLS_HEAD(&h->listening_hash[i].head,
581 i + LISTENING_NULLS_BASE);
584 EXPORT_SYMBOL_GPL(inet_hashinfo_init);