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/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* Generic TIME_WAIT sockets functions
*
* From code orinally in TCP
*/
#include <linux/config.h>
#include <net/inet_hashtables.h>
#include <net/inet_timewait_sock.h>
/* Must be called with locally disabled BHs. */
void __inet_twsk_kill(struct inet_timewait_sock *tw, struct inet_hashinfo *hashinfo)
{
struct inet_bind_hashbucket *bhead;
struct inet_bind_bucket *tb;
/* Unlink from established hashes. */
struct inet_ehash_bucket *ehead = &hashinfo->ehash[tw->tw_hashent];
write_lock(&ehead->lock);
if (hlist_unhashed(&tw->tw_node)) {
write_unlock(&ehead->lock);
return;
}
__hlist_del(&tw->tw_node);
sk_node_init(&tw->tw_node);
write_unlock(&ehead->lock);
/* Disassociate with bind bucket. */
bhead = &hashinfo->bhash[inet_bhashfn(tw->tw_num, hashinfo->bhash_size)];
spin_lock(&bhead->lock);
tb = tw->tw_tb;
__hlist_del(&tw->tw_bind_node);
tw->tw_tb = NULL;
inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb);
spin_unlock(&bhead->lock);
#ifdef SOCK_REFCNT_DEBUG
if (atomic_read(&tw->tw_refcnt) != 1) {
printk(KERN_DEBUG "%s timewait_sock %p refcnt=%d\n",
tw->tw_prot->name, tw, atomic_read(&tw->tw_refcnt));
}
#endif
inet_twsk_put(tw);
}
/*
* Enter the time wait state. This is called with locally disabled BH.
* Essentially we whip up a timewait bucket, copy the relevant info into it
* from the SK, and mess with hash chains and list linkage.
*/
void __inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
struct inet_hashinfo *hashinfo)
{
const struct inet_sock *inet = inet_sk(sk);
struct inet_ehash_bucket *ehead = &hashinfo->ehash[sk->sk_hashent];
struct inet_bind_hashbucket *bhead;
/* Step 1: Put TW into bind hash. Original socket stays there too.
Note, that any socket with inet->num != 0 MUST be bound in
binding cache, even if it is closed.
*/
bhead = &hashinfo->bhash[inet_bhashfn(inet->num, hashinfo->bhash_size)];
spin_lock(&bhead->lock);
tw->tw_tb = inet->bind_hash;
BUG_TRAP(inet->bind_hash);
inet_twsk_add_bind_node(tw, &tw->tw_tb->owners);
spin_unlock(&bhead->lock);
write_lock(&ehead->lock);
/* Step 2: Remove SK from established hash. */
if (__sk_del_node_init(sk))
sock_prot_dec_use(sk->sk_prot);
/* Step 3: Hash TW into TIMEWAIT half of established hash table. */
inet_twsk_add_node(tw, &(ehead + hashinfo->ehash_size)->chain);
atomic_inc(&tw->tw_refcnt);
write_unlock(&ehead->lock);
}
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