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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. * * 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> /* 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_nulls_head chain;	struct hlist_nulls_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 {#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;}; /* * Sockets can be hashed in established or listening table * We must use different 'nulls' end-of-chain value for listening * hash table, or we might find a socket that was closed and * reallocated/inserted into established hash table */#define LISTENING_NULLS_BASE (1U << 29)struct inet_listen_hashbucket {	spinlock_t		lock;	struct hlist_nulls_head	head;}; /* 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;	spinlock_t			*ehash_locks;	unsigned int			ehash_mask;	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;	/* 4 bytes hole on 64 bit */ 	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.	 */	/* 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 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); /* These can have wildcards, don't try too hard. */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);} /* Caller must disable local BH processing. */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);} /* 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)) && 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 /* 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)) && 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 /* 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;} 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 /* _INET_HASHTABLES_H */