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 tb
->ib_net
= hold_net(net
);
41 INIT_HLIST_HEAD(&tb
->owners
);
42 hlist_add_head(&tb
->node
, &head
->chain
);
48 * Caller must hold hashbucket lock for this tb with local BH disabled
50 void inet_bind_bucket_destroy(struct kmem_cache
*cachep
, struct inet_bind_bucket
*tb
)
52 if (hlist_empty(&tb
->owners
)) {
53 __hlist_del(&tb
->node
);
54 release_net(tb
->ib_net
);
55 kmem_cache_free(cachep
, tb
);
59 void inet_bind_hash(struct sock
*sk
, struct inet_bind_bucket
*tb
,
60 const unsigned short snum
)
62 inet_sk(sk
)->num
= snum
;
63 sk_add_bind_node(sk
, &tb
->owners
);
64 inet_csk(sk
)->icsk_bind_hash
= tb
;
68 * Get rid of any references to a local port held by the given sock.
70 static void __inet_put_port(struct sock
*sk
)
72 struct inet_hashinfo
*hashinfo
= sk
->sk_prot
->h
.hashinfo
;
73 const int bhash
= inet_bhashfn(inet_sk(sk
)->num
, hashinfo
->bhash_size
);
74 struct inet_bind_hashbucket
*head
= &hashinfo
->bhash
[bhash
];
75 struct inet_bind_bucket
*tb
;
77 spin_lock(&head
->lock
);
78 tb
= inet_csk(sk
)->icsk_bind_hash
;
79 __sk_del_bind_node(sk
);
80 inet_csk(sk
)->icsk_bind_hash
= NULL
;
82 inet_bind_bucket_destroy(hashinfo
->bind_bucket_cachep
, tb
);
83 spin_unlock(&head
->lock
);
86 void inet_put_port(struct sock
*sk
)
93 EXPORT_SYMBOL(inet_put_port
);
96 * This lock without WQ_FLAG_EXCLUSIVE is good on UP and it can be very bad on SMP.
97 * Look, when several writers sleep and reader wakes them up, all but one
98 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
99 * this, _but_ remember, it adds useless work on UP machines (wake up each
100 * exclusive lock release). It should be ifdefed really.
102 void inet_listen_wlock(struct inet_hashinfo
*hashinfo
)
103 __acquires(hashinfo
->lhash_lock
)
105 write_lock(&hashinfo
->lhash_lock
);
107 if (atomic_read(&hashinfo
->lhash_users
)) {
111 prepare_to_wait_exclusive(&hashinfo
->lhash_wait
,
112 &wait
, TASK_UNINTERRUPTIBLE
);
113 if (!atomic_read(&hashinfo
->lhash_users
))
115 write_unlock_bh(&hashinfo
->lhash_lock
);
117 write_lock_bh(&hashinfo
->lhash_lock
);
120 finish_wait(&hashinfo
->lhash_wait
, &wait
);
125 * Don't inline this cruft. Here are some nice properties to exploit here. The
126 * BSD API does not allow a listening sock to specify the remote port nor the
127 * remote address for the connection. So always assume those are both
128 * wildcarded during the search since they can never be otherwise.
130 static struct sock
*inet_lookup_listener_slow(struct net
*net
,
131 const struct hlist_head
*head
,
133 const unsigned short hnum
,
136 struct sock
*result
= NULL
, *sk
;
137 const struct hlist_node
*node
;
140 sk_for_each(sk
, node
, head
) {
141 const struct inet_sock
*inet
= inet_sk(sk
);
143 if (net_eq(sock_net(sk
), net
) && inet
->num
== hnum
&&
144 !ipv6_only_sock(sk
)) {
145 const __be32 rcv_saddr
= inet
->rcv_saddr
;
146 int score
= sk
->sk_family
== PF_INET
? 1 : 0;
149 if (rcv_saddr
!= daddr
)
153 if (sk
->sk_bound_dev_if
) {
154 if (sk
->sk_bound_dev_if
!= dif
)
160 if (score
> hiscore
) {
169 /* Optimize the common listener case. */
170 struct sock
*__inet_lookup_listener(struct net
*net
,
171 struct inet_hashinfo
*hashinfo
,
172 const __be32 daddr
, const unsigned short hnum
,
175 struct sock
*sk
= NULL
;
176 const struct hlist_head
*head
;
178 read_lock(&hashinfo
->lhash_lock
);
179 head
= &hashinfo
->listening_hash
[inet_lhashfn(hnum
)];
180 if (!hlist_empty(head
)) {
181 const struct inet_sock
*inet
= inet_sk((sk
= __sk_head(head
)));
183 if (inet
->num
== hnum
&& !sk
->sk_node
.next
&&
184 (!inet
->rcv_saddr
|| inet
->rcv_saddr
== daddr
) &&
185 (sk
->sk_family
== PF_INET
|| !ipv6_only_sock(sk
)) &&
186 !sk
->sk_bound_dev_if
&& net_eq(sock_net(sk
), net
))
188 sk
= inet_lookup_listener_slow(net
, head
, daddr
, hnum
, dif
);
194 read_unlock(&hashinfo
->lhash_lock
);
197 EXPORT_SYMBOL_GPL(__inet_lookup_listener
);
199 struct sock
* __inet_lookup_established(struct net
*net
,
200 struct inet_hashinfo
*hashinfo
,
201 const __be32 saddr
, const __be16 sport
,
202 const __be32 daddr
, const u16 hnum
,
205 INET_ADDR_COOKIE(acookie
, saddr
, daddr
)
206 const __portpair ports
= INET_COMBINED_PORTS(sport
, hnum
);
208 const struct hlist_node
*node
;
209 /* Optimize here for direct hit, only listening connections can
210 * have wildcards anyways.
212 unsigned int hash
= inet_ehashfn(daddr
, hnum
, saddr
, sport
);
213 struct inet_ehash_bucket
*head
= inet_ehash_bucket(hashinfo
, hash
);
214 rwlock_t
*lock
= inet_ehash_lockp(hashinfo
, hash
);
216 prefetch(head
->chain
.first
);
218 sk_for_each(sk
, node
, &head
->chain
) {
219 if (INET_MATCH(sk
, net
, hash
, acookie
,
220 saddr
, daddr
, ports
, dif
))
221 goto hit
; /* You sunk my battleship! */
224 /* Must check for a TIME_WAIT'er before going to listener hash. */
225 sk_for_each(sk
, node
, &head
->twchain
) {
226 if (INET_TW_MATCH(sk
, net
, hash
, acookie
,
227 saddr
, daddr
, ports
, dif
))
238 EXPORT_SYMBOL_GPL(__inet_lookup_established
);
240 /* called with local bh disabled */
241 static int __inet_check_established(struct inet_timewait_death_row
*death_row
,
242 struct sock
*sk
, __u16 lport
,
243 struct inet_timewait_sock
**twp
)
245 struct inet_hashinfo
*hinfo
= death_row
->hashinfo
;
246 struct inet_sock
*inet
= inet_sk(sk
);
247 __be32 daddr
= inet
->rcv_saddr
;
248 __be32 saddr
= inet
->daddr
;
249 int dif
= sk
->sk_bound_dev_if
;
250 INET_ADDR_COOKIE(acookie
, saddr
, daddr
)
251 const __portpair ports
= INET_COMBINED_PORTS(inet
->dport
, lport
);
252 unsigned int hash
= inet_ehashfn(daddr
, lport
, saddr
, inet
->dport
);
253 struct inet_ehash_bucket
*head
= inet_ehash_bucket(hinfo
, hash
);
254 rwlock_t
*lock
= inet_ehash_lockp(hinfo
, hash
);
256 const struct hlist_node
*node
;
257 struct inet_timewait_sock
*tw
;
258 struct net
*net
= sock_net(sk
);
260 prefetch(head
->chain
.first
);
263 /* Check TIME-WAIT sockets first. */
264 sk_for_each(sk2
, node
, &head
->twchain
) {
267 if (INET_TW_MATCH(sk2
, net
, hash
, acookie
,
268 saddr
, daddr
, ports
, dif
)) {
269 if (twsk_unique(sk
, sk2
, twp
))
277 /* And established part... */
278 sk_for_each(sk2
, node
, &head
->chain
) {
279 if (INET_MATCH(sk2
, net
, hash
, acookie
,
280 saddr
, daddr
, ports
, dif
))
285 /* Must record num and sport now. Otherwise we will see
286 * in hash table socket with a funny identity. */
288 inet
->sport
= htons(lport
);
290 BUG_TRAP(sk_unhashed(sk
));
291 __sk_add_node(sk
, &head
->chain
);
292 sock_prot_inuse_add(sock_net(sk
), sk
->sk_prot
, 1);
297 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED
);
299 /* Silly. Should hash-dance instead... */
300 inet_twsk_deschedule(tw
, death_row
);
301 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED
);
310 return -EADDRNOTAVAIL
;
313 static inline u32
inet_sk_port_offset(const struct sock
*sk
)
315 const struct inet_sock
*inet
= inet_sk(sk
);
316 return secure_ipv4_port_ephemeral(inet
->rcv_saddr
, inet
->daddr
,
320 void __inet_hash_nolisten(struct sock
*sk
)
322 struct inet_hashinfo
*hashinfo
= sk
->sk_prot
->h
.hashinfo
;
323 struct hlist_head
*list
;
325 struct inet_ehash_bucket
*head
;
327 BUG_TRAP(sk_unhashed(sk
));
329 sk
->sk_hash
= inet_sk_ehashfn(sk
);
330 head
= inet_ehash_bucket(hashinfo
, sk
->sk_hash
);
332 lock
= inet_ehash_lockp(hashinfo
, sk
->sk_hash
);
335 __sk_add_node(sk
, list
);
336 sock_prot_inuse_add(sock_net(sk
), sk
->sk_prot
, 1);
339 EXPORT_SYMBOL_GPL(__inet_hash_nolisten
);
341 static void __inet_hash(struct sock
*sk
)
343 struct inet_hashinfo
*hashinfo
= sk
->sk_prot
->h
.hashinfo
;
344 struct hlist_head
*list
;
347 if (sk
->sk_state
!= TCP_LISTEN
) {
348 __inet_hash_nolisten(sk
);
352 BUG_TRAP(sk_unhashed(sk
));
353 list
= &hashinfo
->listening_hash
[inet_sk_listen_hashfn(sk
)];
354 lock
= &hashinfo
->lhash_lock
;
356 inet_listen_wlock(hashinfo
);
357 __sk_add_node(sk
, list
);
358 sock_prot_inuse_add(sock_net(sk
), sk
->sk_prot
, 1);
360 wake_up(&hashinfo
->lhash_wait
);
363 void inet_hash(struct sock
*sk
)
365 if (sk
->sk_state
!= TCP_CLOSE
) {
371 EXPORT_SYMBOL_GPL(inet_hash
);
373 void inet_unhash(struct sock
*sk
)
376 struct inet_hashinfo
*hashinfo
= sk
->sk_prot
->h
.hashinfo
;
381 if (sk
->sk_state
== TCP_LISTEN
) {
383 inet_listen_wlock(hashinfo
);
384 lock
= &hashinfo
->lhash_lock
;
386 lock
= inet_ehash_lockp(hashinfo
, sk
->sk_hash
);
390 if (__sk_del_node_init(sk
))
391 sock_prot_inuse_add(sock_net(sk
), sk
->sk_prot
, -1);
392 write_unlock_bh(lock
);
394 if (sk
->sk_state
== TCP_LISTEN
)
395 wake_up(&hashinfo
->lhash_wait
);
397 EXPORT_SYMBOL_GPL(inet_unhash
);
399 int __inet_hash_connect(struct inet_timewait_death_row
*death_row
,
400 struct sock
*sk
, u32 port_offset
,
401 int (*check_established
)(struct inet_timewait_death_row
*,
402 struct sock
*, __u16
, struct inet_timewait_sock
**),
403 void (*hash
)(struct sock
*sk
))
405 struct inet_hashinfo
*hinfo
= death_row
->hashinfo
;
406 const unsigned short snum
= inet_sk(sk
)->num
;
407 struct inet_bind_hashbucket
*head
;
408 struct inet_bind_bucket
*tb
;
410 struct net
*net
= sock_net(sk
);
413 int i
, remaining
, low
, high
, port
;
415 u32 offset
= hint
+ port_offset
;
416 struct hlist_node
*node
;
417 struct inet_timewait_sock
*tw
= NULL
;
419 inet_get_local_port_range(&low
, &high
);
420 remaining
= (high
- low
) + 1;
423 for (i
= 1; i
<= remaining
; i
++) {
424 port
= low
+ (i
+ offset
) % remaining
;
425 head
= &hinfo
->bhash
[inet_bhashfn(port
, hinfo
->bhash_size
)];
426 spin_lock(&head
->lock
);
428 /* Does not bother with rcv_saddr checks,
429 * because the established check is already
432 inet_bind_bucket_for_each(tb
, node
, &head
->chain
) {
433 if (tb
->ib_net
== net
&& tb
->port
== port
) {
434 BUG_TRAP(!hlist_empty(&tb
->owners
));
435 if (tb
->fastreuse
>= 0)
437 if (!check_established(death_row
, sk
,
444 tb
= inet_bind_bucket_create(hinfo
->bind_bucket_cachep
,
447 spin_unlock(&head
->lock
);
454 spin_unlock(&head
->lock
);
458 return -EADDRNOTAVAIL
;
463 /* Head lock still held and bh's disabled */
464 inet_bind_hash(sk
, tb
, port
);
465 if (sk_unhashed(sk
)) {
466 inet_sk(sk
)->sport
= htons(port
);
469 spin_unlock(&head
->lock
);
472 inet_twsk_deschedule(tw
, death_row
);
480 head
= &hinfo
->bhash
[inet_bhashfn(snum
, hinfo
->bhash_size
)];
481 tb
= inet_csk(sk
)->icsk_bind_hash
;
482 spin_lock_bh(&head
->lock
);
483 if (sk_head(&tb
->owners
) == sk
&& !sk
->sk_bind_node
.next
) {
485 spin_unlock_bh(&head
->lock
);
488 spin_unlock(&head
->lock
);
489 /* No definite answer... Walk to established hash table */
490 ret
= check_established(death_row
, sk
, snum
, NULL
);
498 * Bind a port for a connect operation and hash it.
500 int inet_hash_connect(struct inet_timewait_death_row
*death_row
,
503 return __inet_hash_connect(death_row
, sk
, inet_sk_port_offset(sk
),
504 __inet_check_established
, __inet_hash_nolisten
);
507 EXPORT_SYMBOL_GPL(inet_hash_connect
);