net/ipv6/inet6_hashtables.c - 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/secure_seq.h>
 #include <net/ip.h>

 u32 inet6_ehashfn(const struct net *net,
 		  const struct in6_addr *laddr, const u16 lport,
 		  const struct in6_addr *faddr, const __be16 fport)
 {
 	static u32 inet6_ehash_secret __read_mostly;
 	static u32 ipv6_hash_secret __read_mostly;

 	u32 lhash, fhash;

 	net_get_random_once(&inet6_ehash_secret, sizeof(inet6_ehash_secret));
 	net_get_random_once(&ipv6_hash_secret, sizeof(ipv6_hash_secret));

 	lhash = (__force u32)laddr->s6_addr32[3];
 	fhash = __ipv6_addr_jhash(faddr, ipv6_hash_secret);

 	return __inet6_ehashfn(lhash, lport, fhash, fport,
 			       inet6_ehash_secret + net_hash_mix(net));
 }

 /*
  * 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 net *net,
 					struct inet_hashinfo *hashinfo,
 					   const struct in6_addr *saddr,
 					   const __be16 sport,
 					   const struct in6_addr *daddr,
 					   const u16 hnum,
 					   const int dif)
 {
 	struct sock *sk;
 	const struct hlist_nulls_node *node;
 	const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
 	/* Optimize here for direct hit, only listening connections can
 	 * have wildcards anyways.
 	 */
 	unsigned int hash = inet6_ehashfn(net, daddr, hnum, saddr, sport);
 	unsigned int slot = hash & hashinfo->ehash_mask;
 	struct inet_ehash_bucket *head = &hashinfo->ehash[slot];


 	rcu_read_lock();
 begin:
 	sk_nulls_for_each_rcu(sk, node, &head->chain) {
 		if (sk->sk_hash != hash)
 			continue;
 		if (!INET6_MATCH(sk, net, saddr, daddr, ports, dif))
 			continue;
 		if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt)))
 			goto out;

 		if (unlikely(!INET6_MATCH(sk, net, saddr, daddr, ports, dif))) {
 			sock_gen_put(sk);
 			goto begin;
 		}
 		goto found;
 	}
 	if (get_nulls_value(node) != slot)
 		goto begin;
 out:
 	sk = NULL;
 found:
 	rcu_read_unlock();
 	return sk;
 }
 EXPORT_SYMBOL(__inet6_lookup_established);

 static inline int compute_score(struct sock *sk, struct net *net,
 				const unsigned short hnum,
 				const struct in6_addr *daddr,
 				const int dif)
 {
 	int score = -1;

 	if (net_eq(sock_net(sk), net) && inet_sk(sk)->inet_num == hnum &&
 	    sk->sk_family == PF_INET6) {

 		score = 1;
 		if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr)) {
 			if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr))
 				return -1;
 			score++;
 		}
 		if (sk->sk_bound_dev_if) {
 			if (sk->sk_bound_dev_if != dif)
 				return -1;
 			score++;
 		}
 		if (sk->sk_incoming_cpu == raw_smp_processor_id())
 			score++;
 	}
 	return score;
 }

 struct sock *inet6_lookup_listener(struct net *net,
 		struct inet_hashinfo *hashinfo, const struct in6_addr *saddr,
 		const __be16 sport, const struct in6_addr *daddr,
 		const unsigned short hnum, const int dif)
 {
 	struct sock *sk;
 	const struct hlist_nulls_node *node;
 	struct sock *result;
 	int score, hiscore, matches = 0, reuseport = 0;
 	u32 phash = 0;
 	unsigned int hash = inet_lhashfn(net, hnum);
 	struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];

 	rcu_read_lock();
 begin:
 	result = NULL;
 	hiscore = 0;
 	sk_nulls_for_each(sk, node, &ilb->head) {
 		score = compute_score(sk, net, hnum, daddr, dif);
 		if (score > hiscore) {
 			hiscore = score;
 			result = sk;
 			reuseport = sk->sk_reuseport;
 			if (reuseport) {
 				phash = inet6_ehashfn(net, daddr, hnum,
 						      saddr, sport);
 				matches = 1;
 			}
 		} else if (score == hiscore && reuseport) {
 			matches++;
 			if (reciprocal_scale(phash, matches) == 0)
 				result = sk;
 			phash = next_pseudo_random32(phash);
 		}
 	}
 	/*
 	 * if the nulls value we got at the end of this lookup is
 	 * not the expected one, we must restart lookup.
 	 * We probably met an item that was moved to another chain.
 	 */
 	if (get_nulls_value(node) != hash + LISTENING_NULLS_BASE)
 		goto begin;
 	if (result) {
 		if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
 			result = NULL;
 		else if (unlikely(compute_score(result, net, hnum, daddr,
 				  dif) < hiscore)) {
 			sock_put(result);
 			goto begin;
 		}
 	}
 	rcu_read_unlock();
 	return result;
 }
 EXPORT_SYMBOL_GPL(inet6_lookup_listener);

 struct sock *inet6_lookup(struct net *net, struct inet_hashinfo *hashinfo,
 			  const struct in6_addr *saddr, const __be16 sport,
 			  const struct in6_addr *daddr, const __be16 dport,
 			  const int dif)
 {
 	struct sock *sk;

 	local_bh_disable();
 	sk = __inet6_lookup(net, 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 in6_addr *daddr = &sk->sk_v6_rcv_saddr;
 	const struct in6_addr *saddr = &sk->sk_v6_daddr;
 	const int dif = sk->sk_bound_dev_if;
 	const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
 	struct net *net = sock_net(sk);
 	const unsigned int hash = inet6_ehashfn(net, daddr, lport, saddr,
 						inet->inet_dport);
 	struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
 	spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
 	struct sock *sk2;
 	const struct hlist_nulls_node *node;
 	struct inet_timewait_sock *tw = NULL;

 	spin_lock(lock);

 	sk_nulls_for_each(sk2, node, &head->chain) {
 		if (sk2->sk_hash != hash)
 			continue;

 		if (likely(INET6_MATCH(sk2, net, saddr, daddr, ports, dif))) {
 			if (sk2->sk_state == TCP_TIME_WAIT) {
 				tw = inet_twsk(sk2);
 				if (twsk_unique(sk, sk2, twp))
 					break;
 			}
 			goto not_unique;
 		}
 	}

 	/* Must record num and sport now. Otherwise we will see
 	 * in hash table socket with a funny identity.
 	 */
 	inet->inet_num = lport;
 	inet->inet_sport = htons(lport);
 	sk->sk_hash = hash;
 	WARN_ON(!sk_unhashed(sk));
 	__sk_nulls_add_node_rcu(sk, &head->chain);
 	if (tw) {
 		sk_nulls_del_node_init_rcu((struct sock *)tw);
 		NET_INC_STATS_BH(net, LINUX_MIB_TIMEWAITRECYCLED);
 	}
 	spin_unlock(lock);
 	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);

 	if (twp) {
 		*twp = tw;
 	} else if (tw) {
 		/* Silly. Should hash-dance instead... */
 		inet_twsk_deschedule_put(tw);
 	}
 	return 0;

 not_unique:
 	spin_unlock(lock);
 	return -EADDRNOTAVAIL;
 }

 static u32 inet6_sk_port_offset(const struct sock *sk)
 {
 	const struct inet_sock *inet = inet_sk(sk);

 	return secure_ipv6_port_ephemeral(sk->sk_v6_rcv_saddr.s6_addr32,
 					  sk->sk_v6_daddr.s6_addr32,
 					  inet->inet_dport);
 }

 int inet6_hash_connect(struct inet_timewait_death_row *death_row,
 		       struct sock *sk)
 {
 	u32 port_offset = 0;

 	if (!inet_sk(sk)->inet_num)
 		port_offset = inet6_sk_port_offset(sk);
 	return __inet_hash_connect(death_row, sk, port_offset,
 				   __inet6_check_established);
 }
 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/secure_seq.h>
	#include <net/ip.h>

	u32 inet6_ehashfn(const struct net *net,
	const struct in6_addr *laddr, const u16 lport,
	const struct in6_addr *faddr, const __be16 fport)
	{
	static u32 inet6_ehash_secret __read_mostly;
	static u32 ipv6_hash_secret __read_mostly;

	u32 lhash, fhash;

	net_get_random_once(&inet6_ehash_secret, sizeof(inet6_ehash_secret));
	net_get_random_once(&ipv6_hash_secret, sizeof(ipv6_hash_secret));

	lhash = (__force u32)laddr->s6_addr32[3];
	fhash = __ipv6_addr_jhash(faddr, ipv6_hash_secret);

	return __inet6_ehashfn(lhash, lport, fhash, fport,
	inet6_ehash_secret + net_hash_mix(net));
	}

	/*
	* 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 net net,
	struct inet_hashinfo *hashinfo,
	const struct in6_addr *saddr,
	const __be16 sport,
	const struct in6_addr *daddr,
	const u16 hnum,
	const int dif)
	{
	struct sock *sk;
	const struct hlist_nulls_node *node;
	const __portpair ports = INET_COMBINED_PORTS(sport, hnum);
	/* Optimize here for direct hit, only listening connections can
	* have wildcards anyways.
	*/
	unsigned int hash = inet6_ehashfn(net, daddr, hnum, saddr, sport);
	unsigned int slot = hash & hashinfo->ehash_mask;
	struct inet_ehash_bucket *head = &hashinfo->ehash[slot];


	rcu_read_lock();
	begin:
	sk_nulls_for_each_rcu(sk, node, &head->chain) {
	if (sk->sk_hash != hash)
	continue;
	if (!INET6_MATCH(sk, net, saddr, daddr, ports, dif))
	continue;
	if (unlikely(!atomic_inc_not_zero(&sk->sk_refcnt)))
	goto out;

	if (unlikely(!INET6_MATCH(sk, net, saddr, daddr, ports, dif))) {
	sock_gen_put(sk);
	goto begin;
	}
	goto found;
	}
	if (get_nulls_value(node) != slot)
	goto begin;
	out:
	sk = NULL;
	found:
	rcu_read_unlock();
	return sk;
	}
	EXPORT_SYMBOL(__inet6_lookup_established);

	static inline int compute_score(struct sock sk, struct net net,
	const unsigned short hnum,
	const struct in6_addr *daddr,
	const int dif)
	{
	int score = -1;

	if (net_eq(sock_net(sk), net) && inet_sk(sk)->inet_num == hnum &&
	sk->sk_family == PF_INET6) {

	score = 1;
	if (!ipv6_addr_any(&sk->sk_v6_rcv_saddr)) {
	if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr))
	return -1;
	score++;
	}
	if (sk->sk_bound_dev_if) {
	if (sk->sk_bound_dev_if != dif)
	return -1;
	score++;
	}
	if (sk->sk_incoming_cpu == raw_smp_processor_id())
	score++;
	}
	return score;
	}

	struct sock inet6_lookup_listener(struct net net,
	struct inet_hashinfo hashinfo, const struct in6_addr saddr,
	const __be16 sport, const struct in6_addr *daddr,
	const unsigned short hnum, const int dif)
	{
	struct sock *sk;
	const struct hlist_nulls_node *node;
	struct sock *result;
	int score, hiscore, matches = 0, reuseport = 0;
	u32 phash = 0;
	unsigned int hash = inet_lhashfn(net, hnum);
	struct inet_listen_hashbucket *ilb = &hashinfo->listening_hash[hash];

	rcu_read_lock();
	begin:
	result = NULL;
	hiscore = 0;
	sk_nulls_for_each(sk, node, &ilb->head) {
	score = compute_score(sk, net, hnum, daddr, dif);
	if (score > hiscore) {
	hiscore = score;
	result = sk;
	reuseport = sk->sk_reuseport;
	if (reuseport) {
	phash = inet6_ehashfn(net, daddr, hnum,
	saddr, sport);
	matches = 1;
	}
	} else if (score == hiscore && reuseport) {
	matches++;
	if (reciprocal_scale(phash, matches) == 0)
	result = sk;
	phash = next_pseudo_random32(phash);
	}
	}
	/*
	* if the nulls value we got at the end of this lookup is
	* not the expected one, we must restart lookup.
	* We probably met an item that was moved to another chain.
	*/
	if (get_nulls_value(node) != hash + LISTENING_NULLS_BASE)
	goto begin;
	if (result) {
	if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
	result = NULL;
	else if (unlikely(compute_score(result, net, hnum, daddr,
	dif) < hiscore)) {
	sock_put(result);
	goto begin;
	}
	}
	rcu_read_unlock();
	return result;
	}
	EXPORT_SYMBOL_GPL(inet6_lookup_listener);

	struct sock inet6_lookup(struct net net, struct inet_hashinfo *hashinfo,
	const struct in6_addr *saddr, const __be16 sport,
	const struct in6_addr *daddr, const __be16 dport,
	const int dif)
	{
	struct sock *sk;

	local_bh_disable();
	sk = __inet6_lookup(net, 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 in6_addr *daddr = &sk->sk_v6_rcv_saddr;
	const struct in6_addr *saddr = &sk->sk_v6_daddr;
	const int dif = sk->sk_bound_dev_if;
	const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
	struct net *net = sock_net(sk);
	const unsigned int hash = inet6_ehashfn(net, daddr, lport, saddr,
	inet->inet_dport);
	struct inet_ehash_bucket *head = inet_ehash_bucket(hinfo, hash);
	spinlock_t *lock = inet_ehash_lockp(hinfo, hash);
	struct sock *sk2;
	const struct hlist_nulls_node *node;
	struct inet_timewait_sock *tw = NULL;

	spin_lock(lock);

	sk_nulls_for_each(sk2, node, &head->chain) {
	if (sk2->sk_hash != hash)
	continue;

	if (likely(INET6_MATCH(sk2, net, saddr, daddr, ports, dif))) {
	if (sk2->sk_state == TCP_TIME_WAIT) {
	tw = inet_twsk(sk2);
	if (twsk_unique(sk, sk2, twp))
	break;
	}
	goto not_unique;
	}
	}

	/* Must record num and sport now. Otherwise we will see
	* in hash table socket with a funny identity.
	*/
	inet->inet_num = lport;
	inet->inet_sport = htons(lport);
	sk->sk_hash = hash;
	WARN_ON(!sk_unhashed(sk));
	__sk_nulls_add_node_rcu(sk, &head->chain);
	if (tw) {
	sk_nulls_del_node_init_rcu((struct sock *)tw);
	NET_INC_STATS_BH(net, LINUX_MIB_TIMEWAITRECYCLED);
	}
	spin_unlock(lock);
	sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);

	if (twp) {
	*twp = tw;
	} else if (tw) {
	/* Silly. Should hash-dance instead... */
	inet_twsk_deschedule_put(tw);
	}
	return 0;

	not_unique:
	spin_unlock(lock);
	return -EADDRNOTAVAIL;
	}

	static u32 inet6_sk_port_offset(const struct sock *sk)
	{
	const struct inet_sock *inet = inet_sk(sk);

	return secure_ipv6_port_ephemeral(sk->sk_v6_rcv_saddr.s6_addr32,
	sk->sk_v6_daddr.s6_addr32,
	inet->inet_dport);
	}

	int inet6_hash_connect(struct inet_timewait_death_row *death_row,
	struct sock *sk)
	{
	u32 port_offset = 0;

	if (!inet_sk(sk)->inet_num)
	port_offset = inet6_sk_port_offset(sk);
	return __inet_hash_connect(death_row, sk, port_offset,
	__inet6_check_established);
	}
	EXPORT_SYMBOL_GPL(inet6_hash_connect);