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

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * 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>
  */

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

 #include <net/addrconf.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>
 #include <net/sock_reuseport.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));
 }
 EXPORT_SYMBOL_GPL(inet6_ehashfn);

 /*
  * 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, const int sdif)
 {
 	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];


 begin:
 	sk_nulls_for_each_rcu(sk, node, &head->chain) {
 		if (sk->sk_hash != hash)
 			continue;
 		if (!inet6_match(net, sk, saddr, daddr, ports, dif, sdif))
 			continue;
 		if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt)))
 			goto out;

 		if (unlikely(!inet6_match(net, sk, saddr, daddr, ports, dif, sdif))) {
 			sock_gen_put(sk);
 			goto begin;
 		}
 		goto found;
 	}
 	if (get_nulls_value(node) != slot)
 		goto begin;
 out:
 	sk = NULL;
 found:
 	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, const int sdif)
 {
 	int score = -1;

 	if (net_eq(sock_net(sk), net) && inet_sk(sk)->inet_num == hnum &&
 	    sk->sk_family == PF_INET6) {
 		if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr))
 			return -1;

 		if (!inet_sk_bound_dev_eq(net, sk->sk_bound_dev_if, dif, sdif))
 			return -1;

 		score =  sk->sk_bound_dev_if ? 2 : 1;
 		if (READ_ONCE(sk->sk_incoming_cpu) == raw_smp_processor_id())
 			score++;
 	}
 	return score;
 }

 /**
  * inet6_lookup_reuseport() - execute reuseport logic on AF_INET6 socket if necessary.
  * @net: network namespace.
  * @sk: AF_INET6 socket, must be in TCP_LISTEN state for TCP or TCP_CLOSE for UDP.
  * @skb: context for a potential SK_REUSEPORT program.
  * @doff: header offset.
  * @saddr: source address.
  * @sport: source port.
  * @daddr: destination address.
  * @hnum: destination port in host byte order.
  * @ehashfn: hash function used to generate the fallback hash.
  *
  * Return: NULL if sk doesn't have SO_REUSEPORT set, otherwise a pointer to
  *         the selected sock or an error.
  */
 struct sock *inet6_lookup_reuseport(struct net *net, struct sock *sk,
 				    struct sk_buff *skb, int doff,
 				    const struct in6_addr *saddr,
 				    __be16 sport,
 				    const struct in6_addr *daddr,
 				    unsigned short hnum,
 				    inet6_ehashfn_t *ehashfn)
 {
 	struct sock *reuse_sk = NULL;
 	u32 phash;

 	if (sk->sk_reuseport) {
 		phash = INDIRECT_CALL_INET(ehashfn, udp6_ehashfn, inet6_ehashfn,
 					   net, daddr, hnum, saddr, sport);
 		reuse_sk = reuseport_select_sock(sk, phash, skb, doff);
 	}
 	return reuse_sk;
 }
 EXPORT_SYMBOL_GPL(inet6_lookup_reuseport);

 /* called with rcu_read_lock() */
 static struct sock *inet6_lhash2_lookup(struct net *net,
 		struct inet_listen_hashbucket *ilb2,
 		struct sk_buff *skb, int doff,
 		const struct in6_addr *saddr,
 		const __be16 sport, const struct in6_addr *daddr,
 		const unsigned short hnum, const int dif, const int sdif)
 {
 	struct sock *sk, *result = NULL;
 	struct hlist_nulls_node *node;
 	int score, hiscore = 0;

 	sk_nulls_for_each_rcu(sk, node, &ilb2->nulls_head) {
 		score = compute_score(sk, net, hnum, daddr, dif, sdif);
 		if (score > hiscore) {
 			result = inet6_lookup_reuseport(net, sk, skb, doff,
 							saddr, sport, daddr, hnum, inet6_ehashfn);
 			if (result)
 				return result;

 			result = sk;
 			hiscore = score;
 		}
 	}

 	return result;
 }

 struct sock *inet6_lookup_run_sk_lookup(struct net *net,
 					int protocol,
 					struct sk_buff *skb, int doff,
 					const struct in6_addr *saddr,
 					const __be16 sport,
 					const struct in6_addr *daddr,
 					const u16 hnum, const int dif,
 					inet6_ehashfn_t *ehashfn)
 {
 	struct sock *sk, *reuse_sk;
 	bool no_reuseport;

 	no_reuseport = bpf_sk_lookup_run_v6(net, protocol, saddr, sport,
 					    daddr, hnum, dif, &sk);
 	if (no_reuseport || IS_ERR_OR_NULL(sk))
 		return sk;

 	reuse_sk = inet6_lookup_reuseport(net, sk, skb, doff,
 					  saddr, sport, daddr, hnum, ehashfn);
 	if (reuse_sk)
 		sk = reuse_sk;
 	return sk;
 }
 EXPORT_SYMBOL_GPL(inet6_lookup_run_sk_lookup);

 struct sock *inet6_lookup_listener(struct net *net,
 		struct inet_hashinfo *hashinfo,
 		struct sk_buff *skb, int doff,
 		const struct in6_addr *saddr,
 		const __be16 sport, const struct in6_addr *daddr,
 		const unsigned short hnum, const int dif, const int sdif)
 {
 	struct inet_listen_hashbucket *ilb2;
 	struct sock *result = NULL;
 	unsigned int hash2;

 	/* Lookup redirect from BPF */
 	if (static_branch_unlikely(&bpf_sk_lookup_enabled) &&
 	    hashinfo == net->ipv4.tcp_death_row.hashinfo) {
 		result = inet6_lookup_run_sk_lookup(net, IPPROTO_TCP, skb, doff,
 						    saddr, sport, daddr, hnum, dif,
 						    inet6_ehashfn);
 		if (result)
 			goto done;
 	}

 	hash2 = ipv6_portaddr_hash(net, daddr, hnum);
 	ilb2 = inet_lhash2_bucket(hashinfo, hash2);

 	result = inet6_lhash2_lookup(net, ilb2, skb, doff,
 				     saddr, sport, daddr, hnum,
 				     dif, sdif);
 	if (result)
 		goto done;

 	/* Lookup lhash2 with in6addr_any */
 	hash2 = ipv6_portaddr_hash(net, &in6addr_any, hnum);
 	ilb2 = inet_lhash2_bucket(hashinfo, hash2);

 	result = inet6_lhash2_lookup(net, ilb2, skb, doff,
 				     saddr, sport, &in6addr_any, hnum,
 				     dif, sdif);
 done:
 	if (IS_ERR(result))
 		return NULL;
 	return result;
 }
 EXPORT_SYMBOL_GPL(inet6_lookup_listener);

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

 	sk = __inet6_lookup(net, hashinfo, skb, doff, saddr, sport, daddr,
 			    ntohs(dport), dif, 0, &refcounted);
 	if (sk && !refcounted && !refcount_inc_not_zero(&sk->sk_refcnt))
 		sk = NULL;
 	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;
 	struct net *net = sock_net(sk);
 	const int sdif = l3mdev_master_ifindex_by_index(net, dif);
 	const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
 	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(net, sk2, saddr, daddr, ports,
 				       dif, sdif))) {
 			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(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 u64 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)
 {
 	u64 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);

 int inet6_hash(struct sock *sk)
 {
 	int err = 0;

 	if (sk->sk_state != TCP_CLOSE)
 		err = __inet_hash(sk, NULL);

 	return err;
 }
 EXPORT_SYMBOL_GPL(inet6_hash);
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* 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>
	*/

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

	#include <net/addrconf.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>
	#include <net/sock_reuseport.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));
	}
	EXPORT_SYMBOL_GPL(inet6_ehashfn);

	/*
	* 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, const int sdif)
	{
	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];


	begin:
	sk_nulls_for_each_rcu(sk, node, &head->chain) {
	if (sk->sk_hash != hash)
	continue;
	if (!inet6_match(net, sk, saddr, daddr, ports, dif, sdif))
	continue;
	if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt)))
	goto out;

	if (unlikely(!inet6_match(net, sk, saddr, daddr, ports, dif, sdif))) {
	sock_gen_put(sk);
	goto begin;
	}
	goto found;
	}
	if (get_nulls_value(node) != slot)
	goto begin;
	out:
	sk = NULL;
	found:
	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, const int sdif)
	{
	int score = -1;

	if (net_eq(sock_net(sk), net) && inet_sk(sk)->inet_num == hnum &&
	sk->sk_family == PF_INET6) {
	if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr))
	return -1;

	if (!inet_sk_bound_dev_eq(net, sk->sk_bound_dev_if, dif, sdif))
	return -1;

	score = sk->sk_bound_dev_if ? 2 : 1;
	if (READ_ONCE(sk->sk_incoming_cpu) == raw_smp_processor_id())
	score++;
	}
	return score;
	}

	/**
	* inet6_lookup_reuseport() - execute reuseport logic on AF_INET6 socket if necessary.
	* @net: network namespace.
	* @sk: AF_INET6 socket, must be in TCP_LISTEN state for TCP or TCP_CLOSE for UDP.
	* @skb: context for a potential SK_REUSEPORT program.
	* @doff: header offset.
	* @saddr: source address.
	* @sport: source port.
	* @daddr: destination address.
	* @hnum: destination port in host byte order.
	* @ehashfn: hash function used to generate the fallback hash.
	*
	* Return: NULL if sk doesn't have SO_REUSEPORT set, otherwise a pointer to
	* the selected sock or an error.
	*/
	struct sock inet6_lookup_reuseport(struct net net, struct sock *sk,
	struct sk_buff *skb, int doff,
	const struct in6_addr *saddr,
	__be16 sport,
	const struct in6_addr *daddr,
	unsigned short hnum,
	inet6_ehashfn_t *ehashfn)
	{
	struct sock *reuse_sk = NULL;
	u32 phash;

	if (sk->sk_reuseport) {
	phash = INDIRECT_CALL_INET(ehashfn, udp6_ehashfn, inet6_ehashfn,
	net, daddr, hnum, saddr, sport);
	reuse_sk = reuseport_select_sock(sk, phash, skb, doff);
	}
	return reuse_sk;
	}
	EXPORT_SYMBOL_GPL(inet6_lookup_reuseport);

	/* called with rcu_read_lock() */
	static struct sock inet6_lhash2_lookup(struct net net,
	struct inet_listen_hashbucket *ilb2,
	struct sk_buff *skb, int doff,
	const struct in6_addr *saddr,
	const __be16 sport, const struct in6_addr *daddr,
	const unsigned short hnum, const int dif, const int sdif)
	{
	struct sock sk, result = NULL;
	struct hlist_nulls_node *node;
	int score, hiscore = 0;

	sk_nulls_for_each_rcu(sk, node, &ilb2->nulls_head) {
	score = compute_score(sk, net, hnum, daddr, dif, sdif);
	if (score > hiscore) {
	result = inet6_lookup_reuseport(net, sk, skb, doff,
	saddr, sport, daddr, hnum, inet6_ehashfn);
	if (result)
	return result;

	result = sk;
	hiscore = score;
	}
	}

	return result;
	}

	struct sock inet6_lookup_run_sk_lookup(struct net net,
	int protocol,
	struct sk_buff *skb, int doff,
	const struct in6_addr *saddr,
	const __be16 sport,
	const struct in6_addr *daddr,
	const u16 hnum, const int dif,
	inet6_ehashfn_t *ehashfn)
	{
	struct sock sk, reuse_sk;
	bool no_reuseport;

	no_reuseport = bpf_sk_lookup_run_v6(net, protocol, saddr, sport,
	daddr, hnum, dif, &sk);
	if (no_reuseport \|\| IS_ERR_OR_NULL(sk))
	return sk;

	reuse_sk = inet6_lookup_reuseport(net, sk, skb, doff,
	saddr, sport, daddr, hnum, ehashfn);
	if (reuse_sk)
	sk = reuse_sk;
	return sk;
	}
	EXPORT_SYMBOL_GPL(inet6_lookup_run_sk_lookup);

	struct sock inet6_lookup_listener(struct net net,
	struct inet_hashinfo *hashinfo,
	struct sk_buff *skb, int doff,
	const struct in6_addr *saddr,
	const __be16 sport, const struct in6_addr *daddr,
	const unsigned short hnum, const int dif, const int sdif)
	{
	struct inet_listen_hashbucket *ilb2;
	struct sock *result = NULL;
	unsigned int hash2;

	/* Lookup redirect from BPF */
	if (static_branch_unlikely(&bpf_sk_lookup_enabled) &&
	hashinfo == net->ipv4.tcp_death_row.hashinfo) {
	result = inet6_lookup_run_sk_lookup(net, IPPROTO_TCP, skb, doff,
	saddr, sport, daddr, hnum, dif,
	inet6_ehashfn);
	if (result)
	goto done;
	}

	hash2 = ipv6_portaddr_hash(net, daddr, hnum);
	ilb2 = inet_lhash2_bucket(hashinfo, hash2);

	result = inet6_lhash2_lookup(net, ilb2, skb, doff,
	saddr, sport, daddr, hnum,
	dif, sdif);
	if (result)
	goto done;

	/* Lookup lhash2 with in6addr_any */
	hash2 = ipv6_portaddr_hash(net, &in6addr_any, hnum);
	ilb2 = inet_lhash2_bucket(hashinfo, hash2);

	result = inet6_lhash2_lookup(net, ilb2, skb, doff,
	saddr, sport, &in6addr_any, hnum,
	dif, sdif);
	done:
	if (IS_ERR(result))
	return NULL;
	return result;
	}
	EXPORT_SYMBOL_GPL(inet6_lookup_listener);

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

	sk = __inet6_lookup(net, hashinfo, skb, doff, saddr, sport, daddr,
	ntohs(dport), dif, 0, &refcounted);
	if (sk && !refcounted && !refcount_inc_not_zero(&sk->sk_refcnt))
	sk = NULL;
	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;
	struct net *net = sock_net(sk);
	const int sdif = l3mdev_master_ifindex_by_index(net, dif);
	const __portpair ports = INET_COMBINED_PORTS(inet->inet_dport, lport);
	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(net, sk2, saddr, daddr, ports,
	dif, sdif))) {
	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(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 u64 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)
	{
	u64 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);

	int inet6_hash(struct sock *sk)
	{
	int err = 0;

	if (sk->sk_state != TCP_CLOSE)
	err = __inet_hash(sk, NULL);

	return err;
	}
	EXPORT_SYMBOL_GPL(inet6_hash);