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>
27 static u32 inet_ehashfn(const struct net *net, const __be32 laddr,
28 const __u16 lport, const __be32 faddr,
31 static u32 inet_ehash_secret __read_mostly;
33 net_get_random_once(&inet_ehash_secret, sizeof(inet_ehash_secret));
35 return __inet_ehashfn(laddr, lport, faddr, fport,
36 inet_ehash_secret + net_hash_mix(net));
39 /* This function handles inet_sock, but also timewait and request sockets
42 u32 sk_ehashfn(const struct sock *sk)
44 #if IS_ENABLED(CONFIG_IPV6)
45 if (sk->sk_family == AF_INET6 &&
46 !ipv6_addr_v4mapped(&sk->sk_v6_daddr))
47 return inet6_ehashfn(sock_net(sk),
48 &sk->sk_v6_rcv_saddr, sk->sk_num,
49 &sk->sk_v6_daddr, sk->sk_dport);
51 return inet_ehashfn(sock_net(sk),
52 sk->sk_rcv_saddr, sk->sk_num,
53 sk->sk_daddr, sk->sk_dport);
57 * Allocate and initialize a new local port bind bucket.
58 * The bindhash mutex for snum's hash chain must be held here.
60 struct inet_bind_bucket *inet_bind_bucket_create(struct kmem_cache *cachep,
62 struct inet_bind_hashbucket *head,
63 const unsigned short snum)
65 struct inet_bind_bucket *tb = kmem_cache_alloc(cachep, GFP_ATOMIC);
68 write_pnet(&tb->ib_net, net);
71 tb->fastreuseport = 0;
73 INIT_HLIST_HEAD(&tb->owners);
74 hlist_add_head(&tb->node, &head->chain);
80 * Caller must hold hashbucket lock for this tb with local BH disabled
82 void inet_bind_bucket_destroy(struct kmem_cache *cachep, struct inet_bind_bucket *tb)
84 if (hlist_empty(&tb->owners)) {
85 __hlist_del(&tb->node);
86 kmem_cache_free(cachep, tb);
90 void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
91 const unsigned short snum)
93 inet_sk(sk)->inet_num = snum;
94 sk_add_bind_node(sk, &tb->owners);
96 inet_csk(sk)->icsk_bind_hash = tb;
100 * Get rid of any references to a local port held by the given sock.
102 static void __inet_put_port(struct sock *sk)
104 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
105 const int bhash = inet_bhashfn(sock_net(sk), inet_sk(sk)->inet_num,
106 hashinfo->bhash_size);
107 struct inet_bind_hashbucket *head = &hashinfo->bhash[bhash];
108 struct inet_bind_bucket *tb;
110 spin_lock(&head->lock);
111 tb = inet_csk(sk)->icsk_bind_hash;
112 __sk_del_bind_node(sk);
114 inet_csk(sk)->icsk_bind_hash = NULL;
115 inet_sk(sk)->inet_num = 0;
116 inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);
117 spin_unlock(&head->lock);
120 void inet_put_port(struct sock *sk)
126 EXPORT_SYMBOL(inet_put_port);
128 int __inet_inherit_port(struct sock *sk, struct sock *child)
130 struct inet_hashinfo *table = sk->sk_prot->h.hashinfo;
131 unsigned short port = inet_sk(child)->inet_num;
132 const int bhash = inet_bhashfn(sock_net(sk), port,
134 struct inet_bind_hashbucket *head = &table->bhash[bhash];
135 struct inet_bind_bucket *tb;
137 spin_lock(&head->lock);
138 tb = inet_csk(sk)->icsk_bind_hash;
139 if (tb->port != port) {
140 /* NOTE: using tproxy and redirecting skbs to a proxy
141 * on a different listener port breaks the assumption
142 * that the listener socket's icsk_bind_hash is the same
143 * as that of the child socket. We have to look up or
144 * create a new bind bucket for the child here. */
145 inet_bind_bucket_for_each(tb, &head->chain) {
146 if (net_eq(ib_net(tb), sock_net(sk)) &&
151 tb = inet_bind_bucket_create(table->bind_bucket_cachep,
152 sock_net(sk), head, port);
154 spin_unlock(&head->lock);
159 inet_bind_hash(child, tb, port);
160 spin_unlock(&head->lock);
164 EXPORT_SYMBOL_GPL(__inet_inherit_port);
166 static inline int compute_score(struct sock *sk, struct net *net,
167 const unsigned short hnum, const __be32 daddr,
171 struct inet_sock *inet = inet_sk(sk);
173 if (net_eq(sock_net(sk), net) && inet->inet_num == hnum &&
174 !ipv6_only_sock(sk)) {
175 __be32 rcv_saddr = inet->inet_rcv_saddr;
176 score = sk->sk_family == PF_INET ? 2 : 1;
178 if (rcv_saddr != daddr)
182 if (sk->sk_bound_dev_if) {
183 if (sk->sk_bound_dev_if != dif)
192 * Don't inline this cruft. Here are some nice properties to exploit here. The
193 * BSD API does not allow a listening sock to specify the remote port nor the
194 * remote address for the connection. So always assume those are both
195 * wildcarded during the search since they can never be otherwise.
199 struct sock *__inet_lookup_listener(struct net *net,
200 struct inet_hashinfo *hashinfo,
201 const __be32 saddr, __be16 sport,
202 const __be32 daddr, const unsigned short hnum,
205 struct sock *sk, *result;
206 struct hlist_nulls_node *node;
207 unsigned int hash = inet_lhashfn(net, hnum);
208 struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];
209 int score, hiscore, matches = 0, reuseport = 0;
216 sk_nulls_for_each_rcu(sk, node, &ilb->head) {
217 score = compute_score(sk, net, hnum, daddr, dif);
218 if (score > hiscore) {
221 reuseport = sk->sk_reuseport;
223 phash = inet_ehashfn(net, daddr, hnum,
227 } else if (score == hiscore && reuseport) {
229 if (reciprocal_scale(phash, matches) == 0)
231 phash = next_pseudo_random32(phash);
235 * if the nulls value we got at the end of this lookup is
236 * not the expected one, we must restart lookup.
237 * We probably met an item that was moved to another chain.
239 if (get_nulls_value(node) != hash + LISTENING_NULLS_BASE)
242 if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
244 else if (unlikely(compute_score(result, net, hnum, daddr,
253 EXPORT_SYMBOL_GPL(__inet_lookup_listener);
255 /* All sockets share common refcount, but have different destructors */
256 void sock_gen_put(struct sock *sk)
258 if (!atomic_dec_and_test(&sk->sk_refcnt))
261 if (sk->sk_state == TCP_TIME_WAIT)
262 inet_twsk_free(inet_twsk(sk));
263 else if (sk->sk_state == TCP_NEW_SYN_RECV)
264 reqsk_free(inet_reqsk(sk));
268 EXPORT_SYMBOL_GPL(sock_gen_put);
270 void sock_edemux(struct sk_buff *skb)
272 sock_gen_put(skb->sk);
274 EXPORT_SYMBOL(sock_edemux);
276 struct sock *__inet_lookup_established(struct net *net,
277 struct inet_hashinfo *hashinfo,
278 const __be32 saddr, const __be16 sport,
279 const __be32 daddr, const u16 hnum,
282 INET_ADDR_COOKIE(acookie, saddr, daddr);
283 const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
285 const struct hlist_nulls_node *node;
286 /* Optimize here for direct hit, only listening connections can
287 * have wildcards anyways.
289 unsigned int hash = inet_ehashfn(net, daddr, hnum, saddr, sport);
290 unsigned int slot = hash & hashinfo->ehash_mask;
291 struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
295 sk_nulls_for_each_rcu(sk, node, &head->chain) {
296 if (sk->sk_hash != hash)
298 if (likely(INET_MATCH(sk, net, acookie,
299 saddr, daddr, ports, dif))) {
300 if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt)))
302 if (unlikely(!INET_MATCH(sk, net, acookie,
303 saddr, daddr, ports, dif))) {
311 * if the nulls value we got at the end of this lookup is
312 * not the expected one, we must restart lookup.
313 * We probably met an item that was moved to another chain.
315 if (get_nulls_value(node) != slot)
323 EXPORT_SYMBOL_GPL(__inet_lookup_established);
325 /* called with local bh disabled */
326 static int __inet_check_established(struct inet_timewait_death_row *death_row,
327 struct sock *sk, __u16 lport,
328 struct inet_timewait_sock **twp)
330 struct inet_hashinfo *hinfo = death_row->hashinfo;
331 struct inet_sock *inet = inet_sk(sk);
332 __be32 daddr = inet->inet_rcv_saddr;
333 __be32 saddr = inet->inet_daddr;
334 int dif = sk->sk_bound_dev_if;
335 INET_ADDR_COOKIE(acookie, saddr, daddr);
336 const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
337 struct net *net = sock_net(sk);
338 unsigned int hash = inet_ehashfn(net, daddr, lport,
339 saddr, inet->inet_dport);
340 struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
341 spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
343 const struct hlist_nulls_node *node;
344 struct inet_timewait_sock *tw = NULL;
349 sk_nulls_for_each(sk2, node, &head->chain) {
350 if (sk2->sk_hash != hash)
353 if (likely(INET_MATCH(sk2, net, acookie,
354 saddr, daddr, ports, dif))) {
355 if (sk2->sk_state == TCP_TIME_WAIT) {
357 if (twsk_unique(sk, sk2, twp))
364 /* Must record num and sport now. Otherwise we will see
365 * in hash table socket with a funny identity.
367 inet->inet_num = lport;
368 inet->inet_sport = htons(lport);
370 WARN_ON(!sk_unhashed(sk));
371 __sk_nulls_add_node_rcu(sk, &head->chain);
373 twrefcnt = inet_twsk_unhash(tw);
374 NET_INC_STATS_BH(net, LINUX_MIB_TIMEWAITRECYCLED);
379 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
384 /* Silly. Should hash-dance instead... */
385 inet_twsk_deschedule(tw);
393 return -EADDRNOTAVAIL;
396 static inline u32 inet_sk_port_offset(const struct sock *sk)
398 const struct inet_sock *inet = inet_sk(sk);
399 return secure_ipv4_port_ephemeral(inet->inet_rcv_saddr,
404 int __inet_hash_nolisten(struct sock *sk, struct inet_timewait_sock *tw)
406 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
407 struct hlist_nulls_head *list;
408 struct inet_ehash_bucket *head;
412 WARN_ON(!sk_unhashed(sk));
414 sk->sk_hash = sk_ehashfn(sk);
415 head = inet_ehash_bucket(hashinfo, sk->sk_hash);
417 lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
420 __sk_nulls_add_node_rcu(sk, list);
422 WARN_ON(sk->sk_hash != tw->tw_hash);
423 twrefcnt = inet_twsk_unhash(tw);
426 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
429 EXPORT_SYMBOL_GPL(__inet_hash_nolisten);
431 int __inet_hash(struct sock *sk, struct inet_timewait_sock *tw)
433 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
434 struct inet_listen_hashbucket *ilb;
436 if (sk->sk_state != TCP_LISTEN)
437 return __inet_hash_nolisten(sk, tw);
439 WARN_ON(!sk_unhashed(sk));
440 ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
442 spin_lock(&ilb->lock);
443 __sk_nulls_add_node_rcu(sk, &ilb->head);
444 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
445 spin_unlock(&ilb->lock);
448 EXPORT_SYMBOL(__inet_hash);
450 void inet_hash(struct sock *sk)
452 if (sk->sk_state != TCP_CLOSE) {
454 __inet_hash(sk, NULL);
458 EXPORT_SYMBOL_GPL(inet_hash);
460 void inet_unhash(struct sock *sk)
462 struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
469 if (sk->sk_state == TCP_LISTEN)
470 lock = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)].lock;
472 lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
475 done = __sk_nulls_del_node_init_rcu(sk);
477 sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
478 spin_unlock_bh(lock);
480 EXPORT_SYMBOL_GPL(inet_unhash);
482 int __inet_hash_connect(struct inet_timewait_death_row *death_row,
483 struct sock *sk, u32 port_offset,
484 int (*check_established)(struct inet_timewait_death_row *,
485 struct sock *, __u16, struct inet_timewait_sock **))
487 struct inet_hashinfo *hinfo = death_row->hashinfo;
488 const unsigned short snum = inet_sk(sk)->inet_num;
489 struct inet_bind_hashbucket *head;
490 struct inet_bind_bucket *tb;
492 struct net *net = sock_net(sk);
496 int i, remaining, low, high, port;
498 u32 offset = hint + port_offset;
499 struct inet_timewait_sock *tw = NULL;
501 inet_get_local_port_range(net, &low, &high);
502 remaining = (high - low) + 1;
505 for (i = 1; i <= remaining; i++) {
506 port = low + (i + offset) % remaining;
507 if (inet_is_local_reserved_port(net, port))
509 head = &hinfo->bhash[inet_bhashfn(net, port,
511 spin_lock(&head->lock);
513 /* Does not bother with rcv_saddr checks,
514 * because the established check is already
517 inet_bind_bucket_for_each(tb, &head->chain) {
518 if (net_eq(ib_net(tb), net) &&
520 if (tb->fastreuse >= 0 ||
521 tb->fastreuseport >= 0)
523 WARN_ON(hlist_empty(&tb->owners));
524 if (!check_established(death_row, sk,
531 tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
534 spin_unlock(&head->lock);
538 tb->fastreuseport = -1;
542 spin_unlock(&head->lock);
546 return -EADDRNOTAVAIL;
551 /* Head lock still held and bh's disabled */
552 inet_bind_hash(sk, tb, port);
553 if (sk_unhashed(sk)) {
554 inet_sk(sk)->inet_sport = htons(port);
555 twrefcnt += __inet_hash_nolisten(sk, tw);
558 twrefcnt += inet_twsk_bind_unhash(tw, hinfo);
559 spin_unlock(&head->lock);
562 inet_twsk_deschedule(tw);
573 head = &hinfo->bhash[inet_bhashfn(net, snum, hinfo->bhash_size)];
574 tb = inet_csk(sk)->icsk_bind_hash;
575 spin_lock_bh(&head->lock);
576 if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
577 __inet_hash_nolisten(sk, NULL);
578 spin_unlock_bh(&head->lock);
581 spin_unlock(&head->lock);
582 /* No definite answer... Walk to established hash table */
583 ret = check_established(death_row, sk, snum, NULL);
591 * Bind a port for a connect operation and hash it.
593 int inet_hash_connect(struct inet_timewait_death_row *death_row,
596 return __inet_hash_connect(death_row, sk, inet_sk_port_offset(sk),
597 __inet_check_established);
599 EXPORT_SYMBOL_GPL(inet_hash_connect);
601 void inet_hashinfo_init(struct inet_hashinfo *h)
605 for (i = 0; i < INET_LHTABLE_SIZE; i++) {
606 spin_lock_init(&h->listening_hash[i].lock);
607 INIT_HLIST_NULLS_HEAD(&h->listening_hash[i].head,
608 i + LISTENING_NULLS_BASE);
611 EXPORT_SYMBOL_GPL(inet_hashinfo_init);