include/net/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/ip.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/route.h>
#include <net/tcp_states.h>
#include <net/netns/hash.h>

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

struct inet_ehash_bucket {
	struct hlist_nulls_head chain;
	struct hlist_nulls_head twchain;
};

struct inet_bind_bucket {
#ifdef CONFIG_NET_NS
	struct net		*ib_net;
#endif
	unsigned short		port;
	signed short		fastreuse;
	int			num_owners;
	struct hlist_node	node;
	struct hlist_head	owners;
};

static inline struct net *ib_net(struct inet_bind_bucket *ib)
{
	return read_pnet(&ib->ib_net);
}

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

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

#define LISTENING_NULLS_BASE (1U << 29)
struct inet_listen_hashbucket {
	spinlock_t		lock;
	struct hlist_nulls_head	head;
};

#define INET_LHTABLE_SIZE	32	

struct inet_hashinfo {
	struct inet_ehash_bucket	*ehash;
	spinlock_t			*ehash_locks;
	unsigned int			ehash_mask;
	unsigned int			ehash_locks_mask;

	struct inet_bind_hashbucket	*bhash;

	unsigned int			bhash_size;
	

	struct kmem_cache		*bind_bucket_cachep;

	/* 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
	 * might be often dirty.
	 */
	struct inet_listen_hashbucket	listening_hash[INET_LHTABLE_SIZE]
					____cacheline_aligned_in_smp;

	atomic_t			bsockets;
};

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

static inline spinlock_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(spinlock_t) != 0) {
#ifdef CONFIG_NUMA
		if (size * sizeof(spinlock_t) > PAGE_SIZE)
			hashinfo->ehash_locks = vmalloc(size * sizeof(spinlock_t));
		else
#endif
		hashinfo->ehash_locks =	kmalloc(size * sizeof(spinlock_t),
						GFP_KERNEL);
		if (!hashinfo->ehash_locks)
			return ENOMEM;
		for (i = 0; i < size; i++)
			spin_lock_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(spinlock_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(struct net *net,
		const __u16 lport, const int bhash_size)
{
	return (lport + net_hash_mix(net)) & (bhash_size - 1);
}

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

static inline int inet_lhashfn(struct net *net, const unsigned short num)
{
	return (num + net_hash_mix(net)) & (INET_LHTABLE_SIZE - 1);
}

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

extern int __inet_inherit_port(struct sock *sk, struct sock *child);

extern void inet_put_port(struct sock *sk);

void inet_hashinfo_init(struct inet_hashinfo *h);

extern int __inet_hash_nolisten(struct sock *sk, struct inet_timewait_sock *tw);
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);
}

typedef __u32 __bitwise __portpair;
#ifdef __BIG_ENDIAN
#define INET_COMBINED_PORTS(__sport, __dport) \
	((__force __portpair)(((__force __u32)(__be16)(__sport) << 16) | (__u32)(__dport)))
#else 
#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 
#define INET_ADDR_COOKIE(__name, __saddr, __daddr) \
	const __addrpair __name = (__force __addrpair) ( \
				   (((__force __u64)(__be32)(__daddr)) << 32) | \
				   ((__force __u64)(__be32)(__saddr)));
#endif 
#define INET_MATCH(__sk, __net, __hash, __cookie, __saddr, __daddr, __ports, __dif)\
	(((__sk)->sk_hash == (__hash)) && net_eq(sock_net(__sk), (__net)) &&	\
	 ((*((__addrpair *)&(inet_sk(__sk)->inet_daddr))) == (__cookie))  &&	\
	 ((*((__portpair *)&(inet_sk(__sk)->inet_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)) && net_eq(sock_net(__sk), (__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 
#define INET_ADDR_COOKIE(__name, __saddr, __daddr)
#define INET_MATCH(__sk, __net, __hash, __cookie, __saddr, __daddr, __ports, __dif)	\
	(((__sk)->sk_hash == (__hash)) && net_eq(sock_net(__sk), (__net))	&&	\
	 (inet_sk(__sk)->inet_daddr	== (__saddr))		&&	\
	 (inet_sk(__sk)->inet_rcv_saddr	== (__daddr))		&&	\
	 ((*((__portpair *)&(inet_sk(__sk)->inet_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)) && net_eq(sock_net(__sk), (__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 

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;
}

static inline struct sock *__inet_lookup_skb(struct inet_hashinfo *hashinfo,
					     struct sk_buff *skb,
					     const __be16 sport,
					     const __be16 dport)
{
	struct sock *sk;
	const struct iphdr *iph = ip_hdr(skb);

	if (unlikely(sk = skb_steal_sock(skb)))
		return sk;
	else
		return __inet_lookup(dev_net(skb_dst(skb)->dev), hashinfo,
				     iph->saddr, sport,
				     iph->daddr, dport, inet_iif(skb));
}

extern int __inet_hash_connect(struct inet_timewait_death_row *death_row,
		struct sock *sk,
		u32 port_offset,
		int (*check_established)(struct inet_timewait_death_row *,
			struct sock *, __u16, struct inet_timewait_sock **),
		int (*hash)(struct sock *sk, struct inet_timewait_sock *twp));

extern int inet_hash_connect(struct inet_timewait_death_row *death_row,
			     struct sock *sk);
#endif