net/ipv6/inet6_hashtables.c - maze/linux - Git at Google

 /*
  * 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 INET6 transport hashtables
  *
  * Authors:	Lotsa people, from code originally in tcp, generalised here
  * 		by Arnaldo Carvalho de Melo <acme@mandriva.com>
  *
  *	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.
  */

 #include <linux/module.h>
 #include <linux/random.h>

 #include <net/inet_connection_sock.h>
 #include <net/inet_hashtables.h>
 #include <net/inet6_hashtables.h>
 #include <net/ip.h>

 void __inet6_hash(struct inet_hashinfo *hashinfo,
 				struct sock *sk)
 {
 	struct hlist_head *list;
 	rwlock_t *lock;

 	BUG_TRAP(sk_unhashed(sk));

 	if (sk->sk_state == TCP_LISTEN) {
 		list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
 		lock = &hashinfo->lhash_lock;
 		inet_listen_wlock(hashinfo);
 	} else {
 		unsigned int hash;
 		sk->sk_hash = hash = inet6_sk_ehashfn(sk);
 		hash &= (hashinfo->ehash_size - 1);
 		list = &hashinfo->ehash[hash].chain;
 		lock = &hashinfo->ehash[hash].lock;
 		write_lock(lock);
 	}

 	__sk_add_node(sk, list);
 	sock_prot_inc_use(sk->sk_prot);
 	write_unlock(lock);
 }
 EXPORT_SYMBOL(__inet6_hash);

 /*
  * Sockets in TCP_CLOSE state are _always_ taken out of the hash, so
  * we need not check it for TCP lookups anymore, thanks Alexey. -DaveM
  *
  * The sockhash lock must be held as a reader here.
  */
 struct sock *__inet6_lookup_established(struct inet_hashinfo *hashinfo,
 					   const struct in6_addr *saddr,
 					   const u16 sport,
 					   const struct in6_addr *daddr,
 					   const u16 hnum,
 					   const int dif)
 {
 	struct sock *sk;
 	const struct hlist_node *node;
 	const __u32 ports = INET_COMBINED_PORTS(sport, hnum);
 	/* Optimize here for direct hit, only listening connections can
 	 * have wildcards anyways.
 	 */
 	unsigned int hash = inet6_ehashfn(daddr, hnum, saddr, sport);
 	struct inet_ehash_bucket *head = inet_ehash_bucket(hashinfo, hash);

 	prefetch(head->chain.first);
 	read_lock(&head->lock);
 	sk_for_each(sk, node, &head->chain) {
 		/* For IPV6 do the cheaper port and family tests first. */
 		if (INET6_MATCH(sk, hash, saddr, daddr, ports, dif))
 			goto hit; /* You sunk my battleship! */
 	}
 	/* Must check for a TIME_WAIT'er before going to listener hash. */
 	sk_for_each(sk, node, &(head + hashinfo->ehash_size)->chain) {
 		const struct inet_timewait_sock *tw = inet_twsk(sk);

 		if(*((__u32 *)&(tw->tw_dport))	== ports	&&
 		   sk->sk_family		== PF_INET6) {
 			const struct inet6_timewait_sock *tw6 = inet6_twsk(sk);

 			if (ipv6_addr_equal(&tw6->tw_v6_daddr, saddr)	&&
 			    ipv6_addr_equal(&tw6->tw_v6_rcv_saddr, daddr)	&&
 			    (!sk->sk_bound_dev_if || sk->sk_bound_dev_if == dif))
 				goto hit;
 		}
 	}
 	read_unlock(&head->lock);
 	return NULL;

 hit:
 	sock_hold(sk);
 	read_unlock(&head->lock);
 	return sk;
 }
 EXPORT_SYMBOL(__inet6_lookup_established);

 struct sock *inet6_lookup_listener(struct inet_hashinfo *hashinfo,
 				   const struct in6_addr *daddr,
 				   const unsigned short hnum, const int dif)
 {
 	struct sock *sk;
 	const struct hlist_node *node;
 	struct sock *result = NULL;
 	int score, hiscore = 0;

 	read_lock(&hashinfo->lhash_lock);
 	sk_for_each(sk, node, &hashinfo->listening_hash[inet_lhashfn(hnum)]) {
 		if (inet_sk(sk)->num == hnum && sk->sk_family == PF_INET6) {
 			const struct ipv6_pinfo *np = inet6_sk(sk);

 			score = 1;
 			if (!ipv6_addr_any(&np->rcv_saddr)) {
 				if (!ipv6_addr_equal(&np->rcv_saddr, daddr))
 					continue;
 				score++;
 			}
 			if (sk->sk_bound_dev_if) {
 				if (sk->sk_bound_dev_if != dif)
 					continue;
 				score++;
 			}
 			if (score == 3) {
 				result = sk;
 				break;
 			}
 			if (score > hiscore) {
 				hiscore = score;
 				result = sk;
 			}
 		}
 	}
 	if (result)
 		sock_hold(result);
 	read_unlock(&hashinfo->lhash_lock);
 	return result;
 }

 EXPORT_SYMBOL_GPL(inet6_lookup_listener);

 struct sock *inet6_lookup(struct inet_hashinfo *hashinfo,
 			  const struct in6_addr *saddr, const u16 sport,
 			  const struct in6_addr *daddr, const u16 dport,
 			  const int dif)
 {
 	struct sock *sk;

 	local_bh_disable();
 	sk = __inet6_lookup(hashinfo, saddr, sport, daddr, ntohs(dport), dif);
 	local_bh_enable();

 	return sk;
 }

 EXPORT_SYMBOL_GPL(inet6_lookup);

 static int __inet6_check_established(struct inet_timewait_death_row *death_row,
 				     struct sock *sk, const __u16 lport,
 				     struct inet_timewait_sock **twp)
 {
 	struct inet_hashinfo *hinfo = death_row->hashinfo;
 	struct inet_sock *inet = inet_sk(sk);
 	const struct ipv6_pinfo *np = inet6_sk(sk);
 	const struct in6_addr *daddr = &np->rcv_saddr;
 	const struct in6_addr *saddr = &np->daddr;
 	const int dif = sk->sk_bound_dev_if;
 	const u32 ports = INET_COMBINED_PORTS(inet->dport, lport);
 	const unsigned int hash = inet6_ehashfn(daddr, inet->num, saddr,
 						inet->dport);
 	struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
 	struct sock *sk2;
 	const struct hlist_node *node;
 	struct inet_timewait_sock *tw;

 	prefetch(head->chain.first);
 	write_lock(&head->lock);

 	/* Check TIME-WAIT sockets first. */
 	sk_for_each(sk2, node, &(head + hinfo->ehash_size)->chain) {
 		const struct inet6_timewait_sock *tw6 = inet6_twsk(sk2);

 		tw = inet_twsk(sk2);

 		if(*((__u32 *)&(tw->tw_dport)) == ports		 &&
 		   sk2->sk_family	       == PF_INET6	 &&
 		   ipv6_addr_equal(&tw6->tw_v6_daddr, saddr)	 &&
 		   ipv6_addr_equal(&tw6->tw_v6_rcv_saddr, daddr) &&
 		   sk2->sk_bound_dev_if == sk->sk_bound_dev_if) {
 			if (twsk_unique(sk, sk2, twp))
 				goto unique;
 			else
 				goto not_unique;
 		}
 	}
 	tw = NULL;

 	/* And established part... */
 	sk_for_each(sk2, node, &head->chain) {
 		if (INET6_MATCH(sk2, hash, saddr, daddr, ports, dif))
 			goto not_unique;
 	}

 unique:
 	/* Must record num and sport now. Otherwise we will see
 	 * in hash table socket with a funny identity. */
 	inet->num = lport;
 	inet->sport = htons(lport);
 	BUG_TRAP(sk_unhashed(sk));
 	__sk_add_node(sk, &head->chain);
 	sk->sk_hash = hash;
 	sock_prot_inc_use(sk->sk_prot);
 	write_unlock(&head->lock);

 	if (twp != NULL) {
 		*twp = tw;
 		NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
 	} else if (tw != NULL) {
 		/* Silly. Should hash-dance instead... */
 		inet_twsk_deschedule(tw, death_row);
 		NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);

 		inet_twsk_put(tw);
 	}
 	return 0;

 not_unique:
 	write_unlock(&head->lock);
 	return -EADDRNOTAVAIL;
 }

 static inline u32 inet6_sk_port_offset(const struct sock *sk)
 {
 	const struct inet_sock *inet = inet_sk(sk);
 	const struct ipv6_pinfo *np = inet6_sk(sk);
 	return secure_ipv6_port_ephemeral(np->rcv_saddr.s6_addr32,
 					  np->daddr.s6_addr32,
 					  inet->dport);
 }

 int inet6_hash_connect(struct inet_timewait_death_row *death_row,
 		       struct sock *sk)
 {
 	struct inet_hashinfo *hinfo = death_row->hashinfo;
 	const unsigned short snum = inet_sk(sk)->num;
  	struct inet_bind_hashbucket *head;
  	struct inet_bind_bucket *tb;
 	int ret;

  	if (snum == 0) {
  		const int low = sysctl_local_port_range[0];
  		const int high = sysctl_local_port_range[1];
 		const int range = high - low;
  		int i, port;
 		static u32 hint;
 		const u32 offset = hint + inet6_sk_port_offset(sk);
 		struct hlist_node *node;
  		struct inet_timewait_sock *tw = NULL;

  		local_bh_disable();
 		for (i = 1; i <= range; i++) {
 			port = low + (i + offset) % range;
  			head = &hinfo->bhash[inet_bhashfn(port, hinfo->bhash_size)];
  			spin_lock(&head->lock);

  			/* Does not bother with rcv_saddr checks,
  			 * because the established check is already
  			 * unique enough.
  			 */
 			inet_bind_bucket_for_each(tb, node, &head->chain) {
  				if (tb->port == port) {
  					BUG_TRAP(!hlist_empty(&tb->owners));
  					if (tb->fastreuse >= 0)
  						goto next_port;
  					if (!__inet6_check_established(death_row,
 								       sk, port,
 								       &tw))
  						goto ok;
  					goto next_port;
  				}
  			}

  			tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
 						     head, port);
  			if (!tb) {
  				spin_unlock(&head->lock);
  				break;
  			}
  			tb->fastreuse = -1;
  			goto ok;

  		next_port:
  			spin_unlock(&head->lock);
  		}
  		local_bh_enable();

  		return -EADDRNOTAVAIL;

 ok:
 		hint += i;

  		/* Head lock still held and bh's disabled */
  		inet_bind_hash(sk, tb, port);
 		if (sk_unhashed(sk)) {
  			inet_sk(sk)->sport = htons(port);
  			__inet6_hash(hinfo, sk);
  		}
  		spin_unlock(&head->lock);

  		if (tw) {
  			inet_twsk_deschedule(tw, death_row);
  			inet_twsk_put(tw);
  		}

 		ret = 0;
 		goto out;
  	}

  	head = &hinfo->bhash[inet_bhashfn(snum, hinfo->bhash_size)];
  	tb   = inet_csk(sk)->icsk_bind_hash;
 	spin_lock_bh(&head->lock);

 	if (sk_head(&tb->owners) == sk && sk->sk_bind_node.next == NULL) {
 		__inet6_hash(hinfo, sk);
 		spin_unlock_bh(&head->lock);
 		return 0;
 	} else {
 		spin_unlock(&head->lock);
 		/* No definite answer... Walk to established hash table */
 		ret = __inet6_check_established(death_row, sk, snum, NULL);
 out:
 		local_bh_enable();
 		return ret;
 	}
 }

 EXPORT_SYMBOL_GPL(inet6_hash_connect);
	/*
	* 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 INET6 transport hashtables
	*
	* Authors: Lotsa people, from code originally in tcp, generalised here
	* by Arnaldo Carvalho de Melo <acme@mandriva.com>
	*
	* 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.
	*/

	#include <linux/module.h>
	#include <linux/random.h>

	#include <net/inet_connection_sock.h>
	#include <net/inet_hashtables.h>
	#include <net/inet6_hashtables.h>
	#include <net/ip.h>

	void __inet6_hash(struct inet_hashinfo *hashinfo,
	struct sock *sk)
	{
	struct hlist_head *list;
	rwlock_t *lock;

	BUG_TRAP(sk_unhashed(sk));

	if (sk->sk_state == TCP_LISTEN) {
	list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
	lock = &hashinfo->lhash_lock;
	inet_listen_wlock(hashinfo);
	} else {
	unsigned int hash;
	sk->sk_hash = hash = inet6_sk_ehashfn(sk);
	hash &= (hashinfo->ehash_size - 1);
	list = &hashinfo->ehash[hash].chain;
	lock = &hashinfo->ehash[hash].lock;
	write_lock(lock);
	}

	__sk_add_node(sk, list);
	sock_prot_inc_use(sk->sk_prot);
	write_unlock(lock);
	}
	EXPORT_SYMBOL(__inet6_hash);

	/*
	* Sockets in TCP_CLOSE state are _always_ taken out of the hash, so
	* we need not check it for TCP lookups anymore, thanks Alexey. -DaveM
	*
	* The sockhash lock must be held as a reader here.
	*/
	struct sock __inet6_lookup_established(struct inet_hashinfo hashinfo,
	const struct in6_addr *saddr,
	const u16 sport,
	const struct in6_addr *daddr,
	const u16 hnum,
	const int dif)
	{
	struct sock *sk;
	const struct hlist_node *node;
	const __u32 ports = INET_COMBINED_PORTS(sport, hnum);
	/* Optimize here for direct hit, only listening connections can
	* have wildcards anyways.
	*/
	unsigned int hash = inet6_ehashfn(daddr, hnum, saddr, sport);
	struct inet_ehash_bucket *head = inet_ehash_bucket(hashinfo, hash);

	prefetch(head->chain.first);
	read_lock(&head->lock);
	sk_for_each(sk, node, &head->chain) {
	/* For IPV6 do the cheaper port and family tests first. */
	if (INET6_MATCH(sk, hash, saddr, daddr, ports, dif))
	goto hit; /* You sunk my battleship! */
	}
	/* Must check for a TIME_WAIT'er before going to listener hash. */
	sk_for_each(sk, node, &(head + hashinfo->ehash_size)->chain) {
	const struct inet_timewait_sock *tw = inet_twsk(sk);

	if(((__u32 )&(tw->tw_dport)) == ports &&
	sk->sk_family == PF_INET6) {
	const struct inet6_timewait_sock *tw6 = inet6_twsk(sk);

	if (ipv6_addr_equal(&tw6->tw_v6_daddr, saddr) &&
	ipv6_addr_equal(&tw6->tw_v6_rcv_saddr, daddr) &&
	(!sk->sk_bound_dev_if \|\| sk->sk_bound_dev_if == dif))
	goto hit;
	}
	}
	read_unlock(&head->lock);
	return NULL;

	hit:
	sock_hold(sk);
	read_unlock(&head->lock);
	return sk;
	}
	EXPORT_SYMBOL(__inet6_lookup_established);

	struct sock inet6_lookup_listener(struct inet_hashinfo hashinfo,
	const struct in6_addr *daddr,
	const unsigned short hnum, const int dif)
	{
	struct sock *sk;
	const struct hlist_node *node;
	struct sock *result = NULL;
	int score, hiscore = 0;

	read_lock(&hashinfo->lhash_lock);
	sk_for_each(sk, node, &hashinfo->listening_hash[inet_lhashfn(hnum)]) {
	if (inet_sk(sk)->num == hnum && sk->sk_family == PF_INET6) {
	const struct ipv6_pinfo *np = inet6_sk(sk);

	score = 1;
	if (!ipv6_addr_any(&np->rcv_saddr)) {
	if (!ipv6_addr_equal(&np->rcv_saddr, daddr))
	continue;
	score++;
	}
	if (sk->sk_bound_dev_if) {
	if (sk->sk_bound_dev_if != dif)
	continue;
	score++;
	}
	if (score == 3) {
	result = sk;
	break;
	}
	if (score > hiscore) {
	hiscore = score;
	result = sk;
	}
	}
	}
	if (result)
	sock_hold(result);
	read_unlock(&hashinfo->lhash_lock);
	return result;
	}

	EXPORT_SYMBOL_GPL(inet6_lookup_listener);

	struct sock inet6_lookup(struct inet_hashinfo hashinfo,
	const struct in6_addr *saddr, const u16 sport,
	const struct in6_addr *daddr, const u16 dport,
	const int dif)
	{
	struct sock *sk;

	local_bh_disable();
	sk = __inet6_lookup(hashinfo, saddr, sport, daddr, ntohs(dport), dif);
	local_bh_enable();

	return sk;
	}

	EXPORT_SYMBOL_GPL(inet6_lookup);

	static int __inet6_check_established(struct inet_timewait_death_row *death_row,
	struct sock *sk, const __u16 lport,
	struct inet_timewait_sock **twp)
	{
	struct inet_hashinfo *hinfo = death_row->hashinfo;
	struct inet_sock *inet = inet_sk(sk);
	const struct ipv6_pinfo *np = inet6_sk(sk);
	const struct in6_addr *daddr = &np->rcv_saddr;
	const struct in6_addr *saddr = &np->daddr;
	const int dif = sk->sk_bound_dev_if;
	const u32 ports = INET_COMBINED_PORTS(inet->dport, lport);
	const unsigned int hash = inet6_ehashfn(daddr, inet->num, saddr,
	inet->dport);
	struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
	struct sock *sk2;
	const struct hlist_node *node;
	struct inet_timewait_sock *tw;

	prefetch(head->chain.first);
	write_lock(&head->lock);

	/* Check TIME-WAIT sockets first. */
	sk_for_each(sk2, node, &(head + hinfo->ehash_size)->chain) {
	const struct inet6_timewait_sock *tw6 = inet6_twsk(sk2);

	tw = inet_twsk(sk2);

	if(((__u32 )&(tw->tw_dport)) == ports &&
	sk2->sk_family == PF_INET6 &&
	ipv6_addr_equal(&tw6->tw_v6_daddr, saddr) &&
	ipv6_addr_equal(&tw6->tw_v6_rcv_saddr, daddr) &&
	sk2->sk_bound_dev_if == sk->sk_bound_dev_if) {
	if (twsk_unique(sk, sk2, twp))
	goto unique;
	else
	goto not_unique;
	}
	}
	tw = NULL;

	/* And established part... */
	sk_for_each(sk2, node, &head->chain) {
	if (INET6_MATCH(sk2, hash, saddr, daddr, ports, dif))
	goto not_unique;
	}

	unique:
	/* Must record num and sport now. Otherwise we will see
	* in hash table socket with a funny identity. */
	inet->num = lport;
	inet->sport = htons(lport);
	BUG_TRAP(sk_unhashed(sk));
	__sk_add_node(sk, &head->chain);
	sk->sk_hash = hash;
	sock_prot_inc_use(sk->sk_prot);
	write_unlock(&head->lock);

	if (twp != NULL) {
	*twp = tw;
	NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);
	} else if (tw != NULL) {
	/* Silly. Should hash-dance instead... */
	inet_twsk_deschedule(tw, death_row);
	NET_INC_STATS_BH(LINUX_MIB_TIMEWAITRECYCLED);

	inet_twsk_put(tw);
	}
	return 0;

	not_unique:
	write_unlock(&head->lock);
	return -EADDRNOTAVAIL;
	}

	static inline u32 inet6_sk_port_offset(const struct sock *sk)
	{
	const struct inet_sock *inet = inet_sk(sk);
	const struct ipv6_pinfo *np = inet6_sk(sk);
	return secure_ipv6_port_ephemeral(np->rcv_saddr.s6_addr32,
	np->daddr.s6_addr32,
	inet->dport);
	}

	int inet6_hash_connect(struct inet_timewait_death_row *death_row,
	struct sock *sk)
	{
	struct inet_hashinfo *hinfo = death_row->hashinfo;
	const unsigned short snum = inet_sk(sk)->num;
	struct inet_bind_hashbucket *head;
	struct inet_bind_bucket *tb;
	int ret;

	if (snum == 0) {
	const int low = sysctl_local_port_range[0];
	const int high = sysctl_local_port_range[1];
	const int range = high - low;
	int i, port;
	static u32 hint;
	const u32 offset = hint + inet6_sk_port_offset(sk);
	struct hlist_node *node;
	struct inet_timewait_sock *tw = NULL;

	local_bh_disable();
	for (i = 1; i <= range; i++) {
	port = low + (i + offset) % range;
	head = &hinfo->bhash[inet_bhashfn(port, hinfo->bhash_size)];
	spin_lock(&head->lock);

	/* Does not bother with rcv_saddr checks,
	* because the established check is already
	* unique enough.
	*/
	inet_bind_bucket_for_each(tb, node, &head->chain) {
	if (tb->port == port) {
	BUG_TRAP(!hlist_empty(&tb->owners));
	if (tb->fastreuse >= 0)
	goto next_port;
	if (!__inet6_check_established(death_row,
	sk, port,
	&tw))
	goto ok;
	goto next_port;
	}
	}

	tb = inet_bind_bucket_create(hinfo->bind_bucket_cachep,
	head, port);
	if (!tb) {
	spin_unlock(&head->lock);
	break;
	}
	tb->fastreuse = -1;
	goto ok;

	next_port:
	spin_unlock(&head->lock);
	}
	local_bh_enable();

	return -EADDRNOTAVAIL;

	ok:
	hint += i;

	/* Head lock still held and bh's disabled */
	inet_bind_hash(sk, tb, port);
	if (sk_unhashed(sk)) {
	inet_sk(sk)->sport = htons(port);
	__inet6_hash(hinfo, sk);
	}
	spin_unlock(&head->lock);

	if (tw) {
	inet_twsk_deschedule(tw, death_row);
	inet_twsk_put(tw);
	}

	ret = 0;
	goto out;
	}

	head = &hinfo->bhash[inet_bhashfn(snum, hinfo->bhash_size)];
	tb = inet_csk(sk)->icsk_bind_hash;
	spin_lock_bh(&head->lock);

	if (sk_head(&tb->owners) == sk && sk->sk_bind_node.next == NULL) {
	__inet6_hash(hinfo, sk);
	spin_unlock_bh(&head->lock);
	return 0;
	} else {
	spin_unlock(&head->lock);
	/* No definite answer... Walk to established hash table */
	ret = __inet6_check_established(death_row, sk, snum, NULL);
	out:
	local_bh_enable();
	return ret;
	}
	}

	EXPORT_SYMBOL_GPL(inet6_hash_connect);