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/config.h>
17 #include <linux/module.h>
18 #include <linux/random.h>
19 #include <linux/sched.h>
20 #include <linux/slab.h>
21 #include <linux/wait.h>
23 #include <net/inet_connection_sock.h>
24 #include <net/inet_hashtables.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(kmem_cache_t
*cachep
,
32 struct inet_bind_hashbucket
*head
,
33 const unsigned short snum
)
35 struct inet_bind_bucket
*tb
= kmem_cache_alloc(cachep
, SLAB_ATOMIC
);
40 INIT_HLIST_HEAD(&tb
->owners
);
41 hlist_add_head(&tb
->node
, &head
->chain
);
47 * Caller must hold hashbucket lock for this tb with local BH disabled
49 void inet_bind_bucket_destroy(kmem_cache_t
*cachep
, struct inet_bind_bucket
*tb
)
51 if (hlist_empty(&tb
->owners
)) {
52 __hlist_del(&tb
->node
);
53 kmem_cache_free(cachep
, tb
);
57 void inet_bind_hash(struct sock
*sk
, struct inet_bind_bucket
*tb
,
58 const unsigned short snum
)
60 inet_sk(sk
)->num
= snum
;
61 sk_add_bind_node(sk
, &tb
->owners
);
62 inet_csk(sk
)->icsk_bind_hash
= tb
;
66 * Get rid of any references to a local port held by the given sock.
68 static void __inet_put_port(struct inet_hashinfo
*hashinfo
, struct sock
*sk
)
70 const int bhash
= inet_bhashfn(inet_sk(sk
)->num
, hashinfo
->bhash_size
);
71 struct inet_bind_hashbucket
*head
= &hashinfo
->bhash
[bhash
];
72 struct inet_bind_bucket
*tb
;
74 spin_lock(&head
->lock
);
75 tb
= inet_csk(sk
)->icsk_bind_hash
;
76 __sk_del_bind_node(sk
);
77 inet_csk(sk
)->icsk_bind_hash
= NULL
;
79 inet_bind_bucket_destroy(hashinfo
->bind_bucket_cachep
, tb
);
80 spin_unlock(&head
->lock
);
83 void inet_put_port(struct inet_hashinfo
*hashinfo
, struct sock
*sk
)
86 __inet_put_port(hashinfo
, sk
);
90 EXPORT_SYMBOL(inet_put_port
);
93 * This lock without WQ_FLAG_EXCLUSIVE is good on UP and it can be very bad on SMP.
94 * Look, when several writers sleep and reader wakes them up, all but one
95 * immediately hit write lock and grab all the cpus. Exclusive sleep solves
96 * this, _but_ remember, it adds useless work on UP machines (wake up each
97 * exclusive lock release). It should be ifdefed really.
99 void inet_listen_wlock(struct inet_hashinfo
*hashinfo
)
101 write_lock(&hashinfo
->lhash_lock
);
103 if (atomic_read(&hashinfo
->lhash_users
)) {
107 prepare_to_wait_exclusive(&hashinfo
->lhash_wait
,
108 &wait
, TASK_UNINTERRUPTIBLE
);
109 if (!atomic_read(&hashinfo
->lhash_users
))
111 write_unlock_bh(&hashinfo
->lhash_lock
);
113 write_lock_bh(&hashinfo
->lhash_lock
);
116 finish_wait(&hashinfo
->lhash_wait
, &wait
);
120 EXPORT_SYMBOL(inet_listen_wlock
);
123 * Don't inline this cruft. Here are some nice properties to exploit here. The
124 * BSD API does not allow a listening sock to specify the remote port nor the
125 * remote address for the connection. So always assume those are both
126 * wildcarded during the search since they can never be otherwise.
128 struct sock
*__inet_lookup_listener(const struct hlist_head
*head
, const u32 daddr
,
129 const unsigned short hnum
, const int dif
)
131 struct sock
*result
= NULL
, *sk
;
132 const struct hlist_node
*node
;
135 sk_for_each(sk
, node
, head
) {
136 const struct inet_sock
*inet
= inet_sk(sk
);
138 if (inet
->num
== hnum
&& !ipv6_only_sock(sk
)) {
139 const __u32 rcv_saddr
= inet
->rcv_saddr
;
140 int score
= sk
->sk_family
== PF_INET
? 1 : 0;
143 if (rcv_saddr
!= daddr
)
147 if (sk
->sk_bound_dev_if
) {
148 if (sk
->sk_bound_dev_if
!= dif
)
154 if (score
> hiscore
) {
163 EXPORT_SYMBOL_GPL(__inet_lookup_listener
);
165 /* called with local bh disabled */
166 static int __inet_check_established(struct inet_timewait_death_row
*death_row
,
167 struct sock
*sk
, __u16 lport
,
168 struct inet_timewait_sock
**twp
)
170 struct inet_hashinfo
*hinfo
= death_row
->hashinfo
;
171 struct inet_sock
*inet
= inet_sk(sk
);
172 u32 daddr
= inet
->rcv_saddr
;
173 u32 saddr
= inet
->daddr
;
174 int dif
= sk
->sk_bound_dev_if
;
175 INET_ADDR_COOKIE(acookie
, saddr
, daddr
)
176 const __u32 ports
= INET_COMBINED_PORTS(inet
->dport
, lport
);
177 unsigned int hash
= inet_ehashfn(daddr
, lport
, saddr
, inet
->dport
);
178 struct inet_ehash_bucket
*head
= inet_ehash_bucket(hinfo
, hash
);
180 const struct hlist_node
*node
;
181 struct inet_timewait_sock
*tw
;
183 prefetch(head
->chain
.first
);
184 write_lock(&head
->lock
);
186 /* Check TIME-WAIT sockets first. */
187 sk_for_each(sk2
, node
, &(head
+ hinfo
->ehash_size
)->chain
) {
190 if (INET_TW_MATCH(sk2
, hash
, acookie
, saddr
, daddr
, ports
, dif
)) {
191 if (twsk_unique(sk
, sk2
, twp
))
199 /* And established part... */
200 sk_for_each(sk2
, node
, &head
->chain
) {
201 if (INET_MATCH(sk2
, hash
, acookie
, saddr
, daddr
, ports
, dif
))
206 /* Must record num and sport now. Otherwise we will see
207 * in hash table socket with a funny identity. */
209 inet
->sport
= htons(lport
);
211 BUG_TRAP(sk_unhashed(sk
));
212 __sk_add_node(sk
, &head
->chain
);
213 sock_prot_inc_use(sk
->sk_prot
);
214 write_unlock(&head
->lock
);
218 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED
);
220 /* Silly. Should hash-dance instead... */
221 inet_twsk_deschedule(tw
, death_row
);
222 NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED
);
230 write_unlock(&head
->lock
);
231 return -EADDRNOTAVAIL
;
234 static inline u32
inet_sk_port_offset(const struct sock
*sk
)
236 const struct inet_sock
*inet
= inet_sk(sk
);
237 return secure_ipv4_port_ephemeral(inet
->rcv_saddr
, inet
->daddr
,
242 * Bind a port for a connect operation and hash it.
244 int inet_hash_connect(struct inet_timewait_death_row
*death_row
,
247 struct inet_hashinfo
*hinfo
= death_row
->hashinfo
;
248 const unsigned short snum
= inet_sk(sk
)->num
;
249 struct inet_bind_hashbucket
*head
;
250 struct inet_bind_bucket
*tb
;
254 int low
= sysctl_local_port_range
[0];
255 int high
= sysctl_local_port_range
[1];
256 int range
= high
- low
;
260 u32 offset
= hint
+ inet_sk_port_offset(sk
);
261 struct hlist_node
*node
;
262 struct inet_timewait_sock
*tw
= NULL
;
265 for (i
= 1; i
<= range
; i
++) {
266 port
= low
+ (i
+ offset
) % range
;
267 head
= &hinfo
->bhash
[inet_bhashfn(port
, hinfo
->bhash_size
)];
268 spin_lock(&head
->lock
);
270 /* Does not bother with rcv_saddr checks,
271 * because the established check is already
274 inet_bind_bucket_for_each(tb
, node
, &head
->chain
) {
275 if (tb
->port
== port
) {
276 BUG_TRAP(!hlist_empty(&tb
->owners
));
277 if (tb
->fastreuse
>= 0)
279 if (!__inet_check_established(death_row
,
287 tb
= inet_bind_bucket_create(hinfo
->bind_bucket_cachep
, head
, port
);
289 spin_unlock(&head
->lock
);
296 spin_unlock(&head
->lock
);
300 return -EADDRNOTAVAIL
;
305 /* Head lock still held and bh's disabled */
306 inet_bind_hash(sk
, tb
, port
);
307 if (sk_unhashed(sk
)) {
308 inet_sk(sk
)->sport
= htons(port
);
309 __inet_hash(hinfo
, sk
, 0);
311 spin_unlock(&head
->lock
);
314 inet_twsk_deschedule(tw
, death_row
);
322 head
= &hinfo
->bhash
[inet_bhashfn(snum
, hinfo
->bhash_size
)];
323 tb
= inet_csk(sk
)->icsk_bind_hash
;
324 spin_lock_bh(&head
->lock
);
325 if (sk_head(&tb
->owners
) == sk
&& !sk
->sk_bind_node
.next
) {
326 __inet_hash(hinfo
, sk
, 0);
327 spin_unlock_bh(&head
->lock
);
330 spin_unlock(&head
->lock
);
331 /* No definite answer... Walk to established hash table */
332 ret
= __inet_check_established(death_row
, sk
, snum
, NULL
);
339 EXPORT_SYMBOL_GPL(inet_hash_connect
);