include/net/inet_hashtables.h - kernel/msm-4.9 - Gitiles

 /*
  * 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.
  *
  * Authors:	Lotsa people, from code originally in tcp
  *
  *	This program is free software; you can redistribute it and/or
  *      modify it under the terms of the GNU General Public License
  *      as published by the Free Software Foundation; either version
  *      2 of the License, or (at your option) any later version.
  */

 #ifndef _INET_HASHTABLES_H
 #define _INET_HASHTABLES_H


 #include <linux/interrupt.h>
 #include <linux/ipv6.h>
 #include <linux/list.h>
 #include <linux/slab.h>
 #include <linux/socket.h>
 #include <linux/spinlock.h>
 #include <linux/types.h>
 #include <linux/wait.h>
 #include <linux/vmalloc.h>

 #include <net/inet_connection_sock.h>
 #include <net/inet_sock.h>
 #include <net/sock.h>
 #include <net/tcp_states.h>

 #include <asm/atomic.h>
 #include <asm/byteorder.h>

 /* This is for all connections with a full identity, no wildcards.
  * One chain is dedicated to TIME_WAIT sockets.
  * I'll experiment with dynamic table growth later.
  */
 struct inet_ehash_bucket {
 	struct hlist_head chain;
 	struct hlist_head twchain;
 };

 /* There are a few simple rules, which allow for local port reuse by
  * an application.  In essence:
  *
  *	1) Sockets bound to different interfaces may share a local port.
  *	   Failing that, goto test 2.
  *	2) If all sockets have sk->sk_reuse set, and none of them are in
  *	   TCP_LISTEN state, the port may be shared.
  *	   Failing that, goto test 3.
  *	3) If all sockets are bound to a specific inet_sk(sk)->rcv_saddr local
  *	   address, and none of them are the same, the port may be
  *	   shared.
  *	   Failing this, the port cannot be shared.
  *
  * The interesting point, is test #2.  This is what an FTP server does
  * all day.  To optimize this case we use a specific flag bit defined
  * below.  As we add sockets to a bind bucket list, we perform a
  * check of: (newsk->sk_reuse && (newsk->sk_state != TCP_LISTEN))
  * As long as all sockets added to a bind bucket pass this test,
  * the flag bit will be set.
  * The resulting situation is that tcp_v[46]_verify_bind() can just check
  * for this flag bit, if it is set and the socket trying to bind has
  * sk->sk_reuse set, we don't even have to walk the owners list at all,
  * we return that it is ok to bind this socket to the requested local port.
  *
  * Sounds like a lot of work, but it is worth it.  In a more naive
  * implementation (ie. current FreeBSD etc.) the entire list of ports
  * must be walked for each data port opened by an ftp server.  Needless
  * to say, this does not scale at all.  With a couple thousand FTP
  * users logged onto your box, isn't it nice to know that new data
  * ports are created in O(1) time?  I thought so. ;-)	-DaveM
  */
 struct inet_bind_bucket {
 	struct net		*ib_net;
 	unsigned short		port;
 	signed short		fastreuse;
 	struct hlist_node	node;
 	struct hlist_head	owners;
 };

 #define inet_bind_bucket_for_each(tb, node, head) \
 	hlist_for_each_entry(tb, node, head, node)

 struct inet_bind_hashbucket {
 	spinlock_t		lock;
 	struct hlist_head	chain;
 };

 /* This is for listening sockets, thus all sockets which possess wildcards. */
 #define INET_LHTABLE_SIZE	32	/* Yes, really, this is all you need. */

 struct inet_hashinfo {
 	/* This is for sockets with full identity only.  Sockets here will
 	 * always be without wildcards and will have the following invariant:
 	 *
 	 *          TCP_ESTABLISHED <= sk->sk_state < TCP_CLOSE
 	 *
 	 * TIME_WAIT sockets use a separate chain (twchain).
 	 */
 	struct inet_ehash_bucket	*ehash;
 	rwlock_t			*ehash_locks;
 	unsigned int			ehash_size;
 	unsigned int			ehash_locks_mask;

 	/* Ok, let's try this, I give up, we do need a local binding
 	 * TCP hash as well as the others for fast bind/connect.
 	 */
 	struct inet_bind_hashbucket	*bhash;

 	unsigned int			bhash_size;
 	/* Note : 4 bytes padding on 64 bit arches */

 	/* All sockets in TCP_LISTEN state will be in here.  This is the only
 	 * table where wildcard'd TCP sockets can exist.  Hash function here
 	 * is just local port number.
 	 */
 	struct hlist_head		listening_hash[INET_LHTABLE_SIZE];

 	/* All the above members are written once at bootup and
 	 * never written again _or_ are predominantly read-access.
 	 *
 	 * Now align to a new cache line as all the following members
 	 * are often dirty.
 	 */
 	rwlock_t			lhash_lock ____cacheline_aligned;
 	atomic_t			lhash_users;
 	wait_queue_head_t		lhash_wait;
 	struct kmem_cache			*bind_bucket_cachep;
 };

 static inline struct inet_ehash_bucket *inet_ehash_bucket(
 	struct inet_hashinfo *hashinfo,
 	unsigned int hash)
 {
 	return &hashinfo->ehash[hash & (hashinfo->ehash_size - 1)];
 }

 static inline rwlock_t *inet_ehash_lockp(
 	struct inet_hashinfo *hashinfo,
 	unsigned int hash)
 {
 	return &hashinfo->ehash_locks[hash & hashinfo->ehash_locks_mask];
 }

 static inline int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo)
 {
 	unsigned int i, size = 256;
 #if defined(CONFIG_PROVE_LOCKING)
 	unsigned int nr_pcpus = 2;
 #else
 	unsigned int nr_pcpus = num_possible_cpus();
 #endif
 	if (nr_pcpus >= 4)
 		size = 512;
 	if (nr_pcpus >= 8)
 		size = 1024;
 	if (nr_pcpus >= 16)
 		size = 2048;
 	if (nr_pcpus >= 32)
 		size = 4096;
 	if (sizeof(rwlock_t) != 0) {
 #ifdef CONFIG_NUMA
 		if (size * sizeof(rwlock_t) > PAGE_SIZE)
 			hashinfo->ehash_locks = vmalloc(size * sizeof(rwlock_t));
 		else
 #endif
 		hashinfo->ehash_locks =	kmalloc(size * sizeof(rwlock_t),
 						GFP_KERNEL);
 		if (!hashinfo->ehash_locks)
 			return ENOMEM;
 		for (i = 0; i < size; i++)
 			rwlock_init(&hashinfo->ehash_locks[i]);
 	}
 	hashinfo->ehash_locks_mask = size - 1;
 	return 0;
 }

 static inline void inet_ehash_locks_free(struct inet_hashinfo *hashinfo)
 {
 	if (hashinfo->ehash_locks) {
 #ifdef CONFIG_NUMA
 		unsigned int size = (hashinfo->ehash_locks_mask + 1) *
 							sizeof(rwlock_t);
 		if (size > PAGE_SIZE)
 			vfree(hashinfo->ehash_locks);
 		else
 #endif
 		kfree(hashinfo->ehash_locks);
 		hashinfo->ehash_locks = NULL;
 	}
 }

 extern struct inet_bind_bucket *
 		    inet_bind_bucket_create(struct kmem_cache *cachep,
 					    struct net *net,
 					    struct inet_bind_hashbucket *head,
 					    const unsigned short snum);
 extern void inet_bind_bucket_destroy(struct kmem_cache *cachep,
 				     struct inet_bind_bucket *tb);

 static inline int inet_bhashfn(const __u16 lport, const int bhash_size)
 {
 	return lport & (bhash_size - 1);
 }

 extern void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
 			   const unsigned short snum);

 /* These can have wildcards, don't try too hard. */
 static inline int inet_lhashfn(const unsigned short num)
 {
 	return num & (INET_LHTABLE_SIZE - 1);
 }

 static inline int inet_sk_listen_hashfn(const struct sock *sk)
 {
 	return inet_lhashfn(inet_sk(sk)->num);
 }

 /* Caller must disable local BH processing. */
 static inline void __inet_inherit_port(struct sock *sk, struct sock *child)
 {
 	struct inet_hashinfo *table = sk->sk_prot->hashinfo;
 	const int bhash = inet_bhashfn(inet_sk(child)->num, table->bhash_size);
 	struct inet_bind_hashbucket *head = &table->bhash[bhash];
 	struct inet_bind_bucket *tb;

 	spin_lock(&head->lock);
 	tb = inet_csk(sk)->icsk_bind_hash;
 	sk_add_bind_node(child, &tb->owners);
 	inet_csk(child)->icsk_bind_hash = tb;
 	spin_unlock(&head->lock);
 }

 static inline void inet_inherit_port(struct sock *sk, struct sock *child)
 {
 	local_bh_disable();
 	__inet_inherit_port(sk, child);
 	local_bh_enable();
 }

 extern void inet_put_port(struct sock *sk);

 extern void inet_listen_wlock(struct inet_hashinfo *hashinfo);

 /*
  * - We may sleep inside this lock.
  * - If sleeping is not required (or called from BH),
  *   use plain read_(un)lock(&inet_hashinfo.lhash_lock).
  */
 static inline void inet_listen_lock(struct inet_hashinfo *hashinfo)
 {
 	/* read_lock synchronizes to candidates to writers */
 	read_lock(&hashinfo->lhash_lock);
 	atomic_inc(&hashinfo->lhash_users);
 	read_unlock(&hashinfo->lhash_lock);
 }

 static inline void inet_listen_unlock(struct inet_hashinfo *hashinfo)
 {
 	if (atomic_dec_and_test(&hashinfo->lhash_users))
 		wake_up(&hashinfo->lhash_wait);
 }

 extern void __inet_hash_nolisten(struct sock *sk);
 extern void inet_hash(struct sock *sk);
 extern void inet_unhash(struct sock *sk);

 extern struct sock *__inet_lookup_listener(struct net *net,
 					   struct inet_hashinfo *hashinfo,
 					   const __be32 daddr,
 					   const unsigned short hnum,
 					   const int dif);

 static inline struct sock *inet_lookup_listener(struct net *net,
 		struct inet_hashinfo *hashinfo,
 		__be32 daddr, __be16 dport, int dif)
 {
 	return __inet_lookup_listener(net, hashinfo, daddr, ntohs(dport), dif);
 }

 /* Socket demux engine toys. */
 /* What happens here is ugly; there's a pair of adjacent fields in
    struct inet_sock; __be16 dport followed by __u16 num.  We want to
    search by pair, so we combine the keys into a single 32bit value
    and compare with 32bit value read from &...->dport.  Let's at least
    make sure that it's not mixed with anything else...
    On 64bit targets we combine comparisons with pair of adjacent __be32
    fields in the same way.
 */
 typedef __u32 __bitwise __portpair;
 #ifdef __BIG_ENDIAN
 #define INET_COMBINED_PORTS(__sport, __dport) \
 	((__force __portpair)(((__force __u32)(__be16)(__sport) << 16) | (__u32)(__dport)))
 #else /* __LITTLE_ENDIAN */
 #define INET_COMBINED_PORTS(__sport, __dport) \
 	((__force __portpair)(((__u32)(__dport) << 16) | (__force __u32)(__be16)(__sport)))
 #endif

 #if (BITS_PER_LONG == 64)
 typedef __u64 __bitwise __addrpair;
 #ifdef __BIG_ENDIAN
 #define INET_ADDR_COOKIE(__name, __saddr, __daddr) \
 	const __addrpair __name = (__force __addrpair) ( \
 				   (((__force __u64)(__be32)(__saddr)) << 32) | \
 				   ((__force __u64)(__be32)(__daddr)));
 #else /* __LITTLE_ENDIAN */
 #define INET_ADDR_COOKIE(__name, __saddr, __daddr) \
 	const __addrpair __name = (__force __addrpair) ( \
 				   (((__force __u64)(__be32)(__daddr)) << 32) | \
 				   ((__force __u64)(__be32)(__saddr)));
 #endif /* __BIG_ENDIAN */
 #define INET_MATCH(__sk, __net, __hash, __cookie, __saddr, __daddr, __ports, __dif)\
 	(((__sk)->sk_hash == (__hash)) && ((__sk)->sk_net == (__net))	&&	\
 	 ((*((__addrpair *)&(inet_sk(__sk)->daddr))) == (__cookie))	&&	\
 	 ((*((__portpair *)&(inet_sk(__sk)->dport))) == (__ports))	&&	\
 	 (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
 #define INET_TW_MATCH(__sk, __net, __hash, __cookie, __saddr, __daddr, __ports, __dif)\
 	(((__sk)->sk_hash == (__hash)) && ((__sk)->sk_net == (__net))	&&	\
 	 ((*((__addrpair *)&(inet_twsk(__sk)->tw_daddr))) == (__cookie)) &&	\
 	 ((*((__portpair *)&(inet_twsk(__sk)->tw_dport))) == (__ports)) &&	\
 	 (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
 #else /* 32-bit arch */
 #define INET_ADDR_COOKIE(__name, __saddr, __daddr)
 #define INET_MATCH(__sk, __net, __hash, __cookie, __saddr, __daddr, __ports, __dif)	\
 	(((__sk)->sk_hash == (__hash)) && ((__sk)->sk_net == (__net))	&&	\
 	 (inet_sk(__sk)->daddr		== (__saddr))		&&	\
 	 (inet_sk(__sk)->rcv_saddr	== (__daddr))		&&	\
 	 ((*((__portpair *)&(inet_sk(__sk)->dport))) == (__ports))	&&	\
 	 (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
 #define INET_TW_MATCH(__sk, __net, __hash,__cookie, __saddr, __daddr, __ports, __dif)	\
 	(((__sk)->sk_hash == (__hash)) && ((__sk)->sk_net == (__net))	&&	\
 	 (inet_twsk(__sk)->tw_daddr	== (__saddr))		&&	\
 	 (inet_twsk(__sk)->tw_rcv_saddr	== (__daddr))		&&	\
 	 ((*((__portpair *)&(inet_twsk(__sk)->tw_dport))) == (__ports)) &&	\
 	 (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
 #endif /* 64-bit arch */

 /*
  * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so we need
  * not check it for lookups anymore, thanks Alexey. -DaveM
  *
  * Local BH must be disabled here.
  */
 extern struct sock * __inet_lookup_established(struct net *net,
 		struct inet_hashinfo *hashinfo,
 		const __be32 saddr, const __be16 sport,
 		const __be32 daddr, const u16 hnum, const int dif);

 static inline struct sock *
 	inet_lookup_established(struct net *net, struct inet_hashinfo *hashinfo,
 				const __be32 saddr, const __be16 sport,
 				const __be32 daddr, const __be16 dport,
 				const int dif)
 {
 	return __inet_lookup_established(net, hashinfo, saddr, sport, daddr,
 					 ntohs(dport), dif);
 }

 static inline struct sock *__inet_lookup(struct net *net,
 					 struct inet_hashinfo *hashinfo,
 					 const __be32 saddr, const __be16 sport,
 					 const __be32 daddr, const __be16 dport,
 					 const int dif)
 {
 	u16 hnum = ntohs(dport);
 	struct sock *sk = __inet_lookup_established(net, hashinfo,
 				saddr, sport, daddr, hnum, dif);

 	return sk ? : __inet_lookup_listener(net, hashinfo, daddr, hnum, dif);
 }

 static inline struct sock *inet_lookup(struct net *net,
 				       struct inet_hashinfo *hashinfo,
 				       const __be32 saddr, const __be16 sport,
 				       const __be32 daddr, const __be16 dport,
 				       const int dif)
 {
 	struct sock *sk;

 	local_bh_disable();
 	sk = __inet_lookup(net, hashinfo, saddr, sport, daddr, dport, dif);
 	local_bh_enable();

 	return sk;
 }

 extern int __inet_hash_connect(struct inet_timewait_death_row *death_row,
 		struct sock *sk,
 		int (*check_established)(struct inet_timewait_death_row *,
 			struct sock *, __u16, struct inet_timewait_sock **),
 			       void (*hash)(struct sock *sk));
 extern int inet_hash_connect(struct inet_timewait_death_row *death_row,
 			     struct sock *sk);
 #endif /* _INET_HASHTABLES_H */
	/*
	* 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.
	*
	* Authors: Lotsa people, from code originally in tcp
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License
	* as published by the Free Software Foundation; either version
	* 2 of the License, or (at your option) any later version.
	*/

	#ifndef _INET_HASHTABLES_H
	#define _INET_HASHTABLES_H


	#include <linux/interrupt.h>
	#include <linux/ipv6.h>
	#include <linux/list.h>
	#include <linux/slab.h>
	#include <linux/socket.h>
	#include <linux/spinlock.h>
	#include <linux/types.h>
	#include <linux/wait.h>
	#include <linux/vmalloc.h>

	#include <net/inet_connection_sock.h>
	#include <net/inet_sock.h>
	#include <net/sock.h>
	#include <net/tcp_states.h>

	#include <asm/atomic.h>
	#include <asm/byteorder.h>

	/* This is for all connections with a full identity, no wildcards.
	* One chain is dedicated to TIME_WAIT sockets.
	* I'll experiment with dynamic table growth later.
	*/
	struct inet_ehash_bucket {
	struct hlist_head chain;
	struct hlist_head twchain;
	};

	/* There are a few simple rules, which allow for local port reuse by
	* an application. In essence:
	*
	* 1) Sockets bound to different interfaces may share a local port.
	* Failing that, goto test 2.
	* 2) If all sockets have sk->sk_reuse set, and none of them are in
	* TCP_LISTEN state, the port may be shared.
	* Failing that, goto test 3.
	* 3) If all sockets are bound to a specific inet_sk(sk)->rcv_saddr local
	* address, and none of them are the same, the port may be
	* shared.
	* Failing this, the port cannot be shared.
	*
	* The interesting point, is test #2. This is what an FTP server does
	* all day. To optimize this case we use a specific flag bit defined
	* below. As we add sockets to a bind bucket list, we perform a
	* check of: (newsk->sk_reuse && (newsk->sk_state != TCP_LISTEN))
	* As long as all sockets added to a bind bucket pass this test,
	* the flag bit will be set.
	* The resulting situation is that tcp_v[46]_verify_bind() can just check
	* for this flag bit, if it is set and the socket trying to bind has
	* sk->sk_reuse set, we don't even have to walk the owners list at all,
	* we return that it is ok to bind this socket to the requested local port.
	*
	* Sounds like a lot of work, but it is worth it. In a more naive
	* implementation (ie. current FreeBSD etc.) the entire list of ports
	* must be walked for each data port opened by an ftp server. Needless
	* to say, this does not scale at all. With a couple thousand FTP
	* users logged onto your box, isn't it nice to know that new data
	* ports are created in O(1) time? I thought so. ;-) -DaveM
	*/
	struct inet_bind_bucket {
	struct net *ib_net;
	unsigned short port;
	signed short fastreuse;
	struct hlist_node node;
	struct hlist_head owners;
	};

	#define inet_bind_bucket_for_each(tb, node, head) \
	hlist_for_each_entry(tb, node, head, node)

	struct inet_bind_hashbucket {
	spinlock_t lock;
	struct hlist_head chain;
	};

	/* This is for listening sockets, thus all sockets which possess wildcards. */
	#define INET_LHTABLE_SIZE 32 /* Yes, really, this is all you need. */

	struct inet_hashinfo {
	/* This is for sockets with full identity only. Sockets here will
	* always be without wildcards and will have the following invariant:
	*
	* TCP_ESTABLISHED <= sk->sk_state < TCP_CLOSE
	*
	* TIME_WAIT sockets use a separate chain (twchain).
	*/
	struct inet_ehash_bucket *ehash;
	rwlock_t *ehash_locks;
	unsigned int ehash_size;
	unsigned int ehash_locks_mask;

	/* Ok, let's try this, I give up, we do need a local binding
	* TCP hash as well as the others for fast bind/connect.
	*/
	struct inet_bind_hashbucket *bhash;

	unsigned int bhash_size;
	/* Note : 4 bytes padding on 64 bit arches */

	/* All sockets in TCP_LISTEN state will be in here. This is the only
	* table where wildcard'd TCP sockets can exist. Hash function here
	* is just local port number.
	*/
	struct hlist_head listening_hash[INET_LHTABLE_SIZE];

	/* All the above members are written once at bootup and
	* never written again _or_ are predominantly read-access.
	*
	* Now align to a new cache line as all the following members
	* are often dirty.
	*/
	rwlock_t lhash_lock ____cacheline_aligned;
	atomic_t lhash_users;
	wait_queue_head_t lhash_wait;
	struct kmem_cache *bind_bucket_cachep;
	};

	static inline struct inet_ehash_bucket *inet_ehash_bucket(
	struct inet_hashinfo *hashinfo,
	unsigned int hash)
	{
	return &hashinfo->ehash[hash & (hashinfo->ehash_size - 1)];
	}

	static inline rwlock_t *inet_ehash_lockp(
	struct inet_hashinfo *hashinfo,
	unsigned int hash)
	{
	return &hashinfo->ehash_locks[hash & hashinfo->ehash_locks_mask];
	}

	static inline int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo)
	{
	unsigned int i, size = 256;
	#if defined(CONFIG_PROVE_LOCKING)
	unsigned int nr_pcpus = 2;
	#else
	unsigned int nr_pcpus = num_possible_cpus();
	#endif
	if (nr_pcpus >= 4)
	size = 512;
	if (nr_pcpus >= 8)
	size = 1024;
	if (nr_pcpus >= 16)
	size = 2048;
	if (nr_pcpus >= 32)
	size = 4096;
	if (sizeof(rwlock_t) != 0) {
	#ifdef CONFIG_NUMA
	if (size * sizeof(rwlock_t) > PAGE_SIZE)
	hashinfo->ehash_locks = vmalloc(size * sizeof(rwlock_t));
	else
	#endif
	hashinfo->ehash_locks = kmalloc(size * sizeof(rwlock_t),
	GFP_KERNEL);
	if (!hashinfo->ehash_locks)
	return ENOMEM;
	for (i = 0; i < size; i++)
	rwlock_init(&hashinfo->ehash_locks[i]);
	}
	hashinfo->ehash_locks_mask = size - 1;
	return 0;
	}

	static inline void inet_ehash_locks_free(struct inet_hashinfo *hashinfo)
	{
	if (hashinfo->ehash_locks) {
	#ifdef CONFIG_NUMA
	unsigned int size = (hashinfo->ehash_locks_mask + 1) *
	sizeof(rwlock_t);
	if (size > PAGE_SIZE)
	vfree(hashinfo->ehash_locks);
	else
	#endif
	kfree(hashinfo->ehash_locks);
	hashinfo->ehash_locks = NULL;
	}
	}

	extern struct inet_bind_bucket *
	inet_bind_bucket_create(struct kmem_cache *cachep,
	struct net *net,
	struct inet_bind_hashbucket *head,
	const unsigned short snum);
	extern void inet_bind_bucket_destroy(struct kmem_cache *cachep,
	struct inet_bind_bucket *tb);

	static inline int inet_bhashfn(const __u16 lport, const int bhash_size)
	{
	return lport & (bhash_size - 1);
	}

	extern void inet_bind_hash(struct sock sk, struct inet_bind_bucket tb,
	const unsigned short snum);

	/* These can have wildcards, don't try too hard. */
	static inline int inet_lhashfn(const unsigned short num)
	{
	return num & (INET_LHTABLE_SIZE - 1);
	}

	static inline int inet_sk_listen_hashfn(const struct sock *sk)
	{
	return inet_lhashfn(inet_sk(sk)->num);
	}

	/* Caller must disable local BH processing. */
	static inline void __inet_inherit_port(struct sock sk, struct sock child)
	{
	struct inet_hashinfo *table = sk->sk_prot->hashinfo;
	const int bhash = inet_bhashfn(inet_sk(child)->num, table->bhash_size);
	struct inet_bind_hashbucket *head = &table->bhash[bhash];
	struct inet_bind_bucket *tb;

	spin_lock(&head->lock);
	tb = inet_csk(sk)->icsk_bind_hash;
	sk_add_bind_node(child, &tb->owners);
	inet_csk(child)->icsk_bind_hash = tb;
	spin_unlock(&head->lock);
	}

	static inline void inet_inherit_port(struct sock sk, struct sock child)
	{
	local_bh_disable();
	__inet_inherit_port(sk, child);
	local_bh_enable();
	}

	extern void inet_put_port(struct sock *sk);

	extern void inet_listen_wlock(struct inet_hashinfo *hashinfo);

	/*
	* - We may sleep inside this lock.
	* - If sleeping is not required (or called from BH),
	* use plain read_(un)lock(&inet_hashinfo.lhash_lock).
	*/
	static inline void inet_listen_lock(struct inet_hashinfo *hashinfo)
	{
	/* read_lock synchronizes to candidates to writers */
	read_lock(&hashinfo->lhash_lock);
	atomic_inc(&hashinfo->lhash_users);
	read_unlock(&hashinfo->lhash_lock);
	}

	static inline void inet_listen_unlock(struct inet_hashinfo *hashinfo)
	{
	if (atomic_dec_and_test(&hashinfo->lhash_users))
	wake_up(&hashinfo->lhash_wait);
	}

	extern void __inet_hash_nolisten(struct sock *sk);
	extern void inet_hash(struct sock *sk);
	extern void inet_unhash(struct sock *sk);

	extern struct sock __inet_lookup_listener(struct net net,
	struct inet_hashinfo *hashinfo,
	const __be32 daddr,
	const unsigned short hnum,
	const int dif);

	static inline struct sock inet_lookup_listener(struct net net,
	struct inet_hashinfo *hashinfo,
	__be32 daddr, __be16 dport, int dif)
	{
	return __inet_lookup_listener(net, hashinfo, daddr, ntohs(dport), dif);
	}

	/* Socket demux engine toys. */
	/* What happens here is ugly; there's a pair of adjacent fields in
	struct inet_sock; __be16 dport followed by __u16 num. We want to
	search by pair, so we combine the keys into a single 32bit value
	and compare with 32bit value read from &...->dport. Let's at least
	make sure that it's not mixed with anything else...
	On 64bit targets we combine comparisons with pair of adjacent __be32
	fields in the same way.
	*/
	typedef __u32 __bitwise __portpair;
	#ifdef __BIG_ENDIAN
	#define INET_COMBINED_PORTS(__sport, __dport) \
	((__force __portpair)(((__force __u32)(__be16)(__sport) << 16) \| (__u32)(__dport)))
	#else /* __LITTLE_ENDIAN */
	#define INET_COMBINED_PORTS(__sport, __dport) \
	((__force __portpair)(((__u32)(__dport) << 16) \| (__force __u32)(__be16)(__sport)))
	#endif

	#if (BITS_PER_LONG == 64)
	typedef __u64 __bitwise __addrpair;
	#ifdef __BIG_ENDIAN
	#define INET_ADDR_COOKIE(__name, __saddr, __daddr) \
	const __addrpair __name = (__force __addrpair) ( \
	(((__force __u64)(__be32)(__saddr)) << 32) \| \
	((__force __u64)(__be32)(__daddr)));
	#else /* __LITTLE_ENDIAN */
	#define INET_ADDR_COOKIE(__name, __saddr, __daddr) \
	const __addrpair __name = (__force __addrpair) ( \
	(((__force __u64)(__be32)(__daddr)) << 32) \| \
	((__force __u64)(__be32)(__saddr)));
	#endif /* __BIG_ENDIAN */
	#define INET_MATCH(__sk, __net, __hash, __cookie, __saddr, __daddr, __ports, __dif)\
	(((__sk)->sk_hash == (__hash)) && ((__sk)->sk_net == (__net)) && \
	((((__addrpair )&(inet_sk(__sk)->daddr))) == (__cookie)) && \
	((((__portpair )&(inet_sk(__sk)->dport))) == (__ports)) && \
	(!((__sk)->sk_bound_dev_if) \|\| ((__sk)->sk_bound_dev_if == (__dif))))
	#define INET_TW_MATCH(__sk, __net, __hash, __cookie, __saddr, __daddr, __ports, __dif)\
	(((__sk)->sk_hash == (__hash)) && ((__sk)->sk_net == (__net)) && \
	((((__addrpair )&(inet_twsk(__sk)->tw_daddr))) == (__cookie)) && \
	((((__portpair )&(inet_twsk(__sk)->tw_dport))) == (__ports)) && \
	(!((__sk)->sk_bound_dev_if) \|\| ((__sk)->sk_bound_dev_if == (__dif))))
	#else /* 32-bit arch */
	#define INET_ADDR_COOKIE(__name, __saddr, __daddr)
	#define INET_MATCH(__sk, __net, __hash, __cookie, __saddr, __daddr, __ports, __dif) \
	(((__sk)->sk_hash == (__hash)) && ((__sk)->sk_net == (__net)) && \
	(inet_sk(__sk)->daddr == (__saddr)) && \
	(inet_sk(__sk)->rcv_saddr == (__daddr)) && \
	((((__portpair )&(inet_sk(__sk)->dport))) == (__ports)) && \
	(!((__sk)->sk_bound_dev_if) \|\| ((__sk)->sk_bound_dev_if == (__dif))))
	#define INET_TW_MATCH(__sk, __net, __hash,__cookie, __saddr, __daddr, __ports, __dif) \
	(((__sk)->sk_hash == (__hash)) && ((__sk)->sk_net == (__net)) && \
	(inet_twsk(__sk)->tw_daddr == (__saddr)) && \
	(inet_twsk(__sk)->tw_rcv_saddr == (__daddr)) && \
	((((__portpair )&(inet_twsk(__sk)->tw_dport))) == (__ports)) && \
	(!((__sk)->sk_bound_dev_if) \|\| ((__sk)->sk_bound_dev_if == (__dif))))
	#endif /* 64-bit arch */

	/*
	* Sockets in TCP_CLOSE state are _always_ taken out of the hash, so we need
	* not check it for lookups anymore, thanks Alexey. -DaveM
	*
	* Local BH must be disabled here.
	*/
	extern struct sock * __inet_lookup_established(struct net *net,
	struct inet_hashinfo *hashinfo,
	const __be32 saddr, const __be16 sport,
	const __be32 daddr, const u16 hnum, const int dif);

	static inline struct sock *
	inet_lookup_established(struct net net, struct inet_hashinfo hashinfo,
	const __be32 saddr, const __be16 sport,
	const __be32 daddr, const __be16 dport,
	const int dif)
	{
	return __inet_lookup_established(net, hashinfo, saddr, sport, daddr,
	ntohs(dport), dif);
	}

	static inline struct sock __inet_lookup(struct net net,
	struct inet_hashinfo *hashinfo,
	const __be32 saddr, const __be16 sport,
	const __be32 daddr, const __be16 dport,
	const int dif)
	{
	u16 hnum = ntohs(dport);
	struct sock *sk = __inet_lookup_established(net, hashinfo,
	saddr, sport, daddr, hnum, dif);

	return sk ? : __inet_lookup_listener(net, hashinfo, daddr, hnum, dif);
	}

	static inline struct sock inet_lookup(struct net net,
	struct inet_hashinfo *hashinfo,
	const __be32 saddr, const __be16 sport,
	const __be32 daddr, const __be16 dport,
	const int dif)
	{
	struct sock *sk;

	local_bh_disable();
	sk = __inet_lookup(net, hashinfo, saddr, sport, daddr, dport, dif);
	local_bh_enable();

	return sk;
	}

	extern int __inet_hash_connect(struct inet_timewait_death_row *death_row,
	struct sock *sk,
	int (check_established)(struct inet_timewait_death_row ,
	struct sock , __u16, struct inet_timewait_sock *),
	void (hash)(struct sock sk));
	extern int inet_hash_connect(struct inet_timewait_death_row *death_row,
	struct sock *sk);
	#endif /* _INET_HASHTABLES_H */