include/net/inet_hashtables.h - 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.
  *
  * Authors:	Lotsa people, from code originally in tcp
  */

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

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

 /* This is for all connections with a full identity, no wildcards.
  * The 'e' prefix stands for Establish, but we really put all sockets
  * but LISTEN ones.
  */
 struct inet_ehash_bucket {
 	struct hlist_nulls_head chain;
 };

 /* 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
  */
 #define FASTREUSEPORT_ANY	1
 #define FASTREUSEPORT_STRICT	2

 struct inet_bind_bucket {
 	possible_net_t		ib_net;
 	int			l3mdev;
 	unsigned short		port;
 	signed char		fastreuse;
 	signed char		fastreuseport;
 	kuid_t			fastuid;
 #if IS_ENABLED(CONFIG_IPV6)
 	struct in6_addr		fast_v6_rcv_saddr;
 #endif
 	__be32			fast_rcv_saddr;
 	unsigned short		fast_sk_family;
 	bool			fast_ipv6_only;
 	struct hlist_node	node;
 	struct hlist_head	owners;
 };

 struct inet_bind2_bucket {
 	possible_net_t		ib_net;
 	int			l3mdev;
 	unsigned short		port;
 #if IS_ENABLED(CONFIG_IPV6)
 	unsigned short		family;
 #endif
 	union {
 #if IS_ENABLED(CONFIG_IPV6)
 		struct in6_addr		v6_rcv_saddr;
 #endif
 		__be32			rcv_saddr;
 	};
 	/* Node in the bhash2 inet_bind_hashbucket chain */
 	struct hlist_node	node;
 	/* List of sockets hashed to this bucket */
 	struct hlist_head	owners;
 };

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

 static inline struct net *ib2_net(const struct inet_bind2_bucket *ib)
 {
 	return read_pnet(&ib->ib_net);
 }

 #define inet_bind_bucket_for_each(tb, head) \
 	hlist_for_each_entry(tb, 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 all hash buckets :
  * A socket might transition from ESTABLISH to LISTEN state without
  * RCU grace period. A lookup in ehash table needs to handle this case.
  */
 #define LISTENING_NULLS_BASE (1U << 29)
 struct inet_listen_hashbucket {
 	spinlock_t		lock;
 	struct hlist_nulls_head	nulls_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
 	 *
 	 */
 	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 kmem_cache		*bind_bucket_cachep;
 	/* This bind table is hashed by local port */
 	struct inet_bind_hashbucket	*bhash;
 	struct kmem_cache		*bind2_bucket_cachep;
 	/* This bind table is hashed by local port and sk->sk_rcv_saddr (ipv4)
 	 * or sk->sk_v6_rcv_saddr (ipv6). This 2nd bind table is used
 	 * primarily for expediting bind conflict resolution.
 	 */
 	struct inet_bind_hashbucket	*bhash2;
 	unsigned int			bhash_size;

 	/* The 2nd listener table hashed by local port and address */
 	unsigned int			lhash2_mask;
 	struct inet_listen_hashbucket	*lhash2;

 	bool				pernet;
 };

 static inline struct inet_hashinfo *tcp_or_dccp_get_hashinfo(const struct sock *sk)
 {
 #if IS_ENABLED(CONFIG_IP_DCCP)
 	return sk->sk_prot->h.hashinfo ? :
 		sock_net(sk)->ipv4.tcp_death_row.hashinfo;
 #else
 	return sock_net(sk)->ipv4.tcp_death_row.hashinfo;
 #endif
 }

 static inline struct inet_listen_hashbucket *
 inet_lhash2_bucket(struct inet_hashinfo *h, u32 hash)
 {
 	return &h->lhash2[hash & h->lhash2_mask];
 }

 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];
 }

 int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo);

 static inline void inet_hashinfo2_free_mod(struct inet_hashinfo *h)
 {
 	kfree(h->lhash2);
 	h->lhash2 = NULL;
 }

 static inline void inet_ehash_locks_free(struct inet_hashinfo *hashinfo)
 {
 	kvfree(hashinfo->ehash_locks);
 	hashinfo->ehash_locks = NULL;
 }

 struct inet_hashinfo *inet_pernet_hashinfo_alloc(struct inet_hashinfo *hashinfo,
 						 unsigned int ehash_entries);
 void inet_pernet_hashinfo_free(struct inet_hashinfo *hashinfo);

 struct inet_bind_bucket *
 inet_bind_bucket_create(struct kmem_cache *cachep, struct net *net,
 			struct inet_bind_hashbucket *head,
 			const unsigned short snum, int l3mdev);
 void inet_bind_bucket_destroy(struct kmem_cache *cachep,
 			      struct inet_bind_bucket *tb);

 bool inet_bind_bucket_match(const struct inet_bind_bucket *tb,
 			    const struct net *net, unsigned short port,
 			    int l3mdev);

 struct inet_bind2_bucket *
 inet_bind2_bucket_create(struct kmem_cache *cachep, struct net *net,
 			 struct inet_bind_hashbucket *head,
 			 unsigned short port, int l3mdev,
 			 const struct sock *sk);

 void inet_bind2_bucket_destroy(struct kmem_cache *cachep,
 			       struct inet_bind2_bucket *tb);

 struct inet_bind2_bucket *
 inet_bind2_bucket_find(const struct inet_bind_hashbucket *head,
 		       const struct net *net,
 		       unsigned short port, int l3mdev,
 		       const struct sock *sk);

 bool inet_bind2_bucket_match_addr_any(const struct inet_bind2_bucket *tb,
 				      const struct net *net, unsigned short port,
 				      int l3mdev, const struct sock *sk);

 static inline u32 inet_bhashfn(const struct net *net, const __u16 lport,
 			       const u32 bhash_size)
 {
 	return (lport + net_hash_mix(net)) & (bhash_size - 1);
 }

 static inline struct inet_bind_hashbucket *
 inet_bhashfn_portaddr(const struct inet_hashinfo *hinfo, const struct sock *sk,
 		      const struct net *net, unsigned short port)
 {
 	u32 hash;

 #if IS_ENABLED(CONFIG_IPV6)
 	if (sk->sk_family == AF_INET6)
 		hash = ipv6_portaddr_hash(net, &sk->sk_v6_rcv_saddr, port);
 	else
 #endif
 		hash = ipv4_portaddr_hash(net, sk->sk_rcv_saddr, port);
 	return &hinfo->bhash2[hash & (hinfo->bhash_size - 1)];
 }

 struct inet_bind_hashbucket *
 inet_bhash2_addr_any_hashbucket(const struct sock *sk, const struct net *net, int port);

 /* This should be called whenever a socket's sk_rcv_saddr (ipv4) or
  * sk_v6_rcv_saddr (ipv6) changes after it has been binded. The socket's
  * rcv_saddr field should already have been updated when this is called.
  */
 int inet_bhash2_update_saddr(struct inet_bind_hashbucket *prev_saddr, struct sock *sk);

 void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
 		    struct inet_bind2_bucket *tb2, unsigned short port);

 /* Caller must disable local BH processing. */
 int __inet_inherit_port(const struct sock *sk, struct sock *child);

 void inet_put_port(struct sock *sk);

 void inet_hashinfo2_init(struct inet_hashinfo *h, const char *name,
 			 unsigned long numentries, int scale,
 			 unsigned long low_limit,
 			 unsigned long high_limit);
 int inet_hashinfo2_init_mod(struct inet_hashinfo *h);

 bool inet_ehash_insert(struct sock *sk, struct sock *osk, bool *found_dup_sk);
 bool inet_ehash_nolisten(struct sock *sk, struct sock *osk,
 			 bool *found_dup_sk);
 int __inet_hash(struct sock *sk, struct sock *osk);
 int inet_hash(struct sock *sk);
 void inet_unhash(struct sock *sk);

 struct sock *__inet_lookup_listener(struct net *net,
 				    struct inet_hashinfo *hashinfo,
 				    struct sk_buff *skb, int doff,
 				    const __be32 saddr, const __be16 sport,
 				    const __be32 daddr,
 				    const unsigned short hnum,
 				    const int dif, const int sdif);

 static inline struct sock *inet_lookup_listener(struct net *net,
 		struct inet_hashinfo *hashinfo,
 		struct sk_buff *skb, int doff,
 		__be32 saddr, __be16 sport,
 		__be32 daddr, __be16 dport, int dif, int sdif)
 {
 	return __inet_lookup_listener(net, hashinfo, skb, doff, saddr, sport,
 				      daddr, ntohs(dport), dif, sdif);
 }

 /* 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.
 */
 #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

 #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 */

 static inline bool inet_match(struct net *net, const struct sock *sk,
 			      const __addrpair cookie, const __portpair ports,
 			      int dif, int sdif)
 {
 	if (!net_eq(sock_net(sk), net) ||
 	    sk->sk_portpair != ports ||
 	    sk->sk_addrpair != cookie)
 	        return false;

 	/* READ_ONCE() paired with WRITE_ONCE() in sock_bindtoindex_locked() */
 	return inet_sk_bound_dev_eq(net, READ_ONCE(sk->sk_bound_dev_if), dif,
 				    sdif);
 }

 /* Sockets in TCP_CLOSE state are _always_ taken out of the hash, so we need
  * not check it for lookups anymore, thanks Alexey. -DaveM
  */
 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, const int sdif);

 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, 0);
 }

 static inline struct sock *__inet_lookup(struct net *net,
 					 struct inet_hashinfo *hashinfo,
 					 struct sk_buff *skb, int doff,
 					 const __be32 saddr, const __be16 sport,
 					 const __be32 daddr, const __be16 dport,
 					 const int dif, const int sdif,
 					 bool *refcounted)
 {
 	u16 hnum = ntohs(dport);
 	struct sock *sk;

 	sk = __inet_lookup_established(net, hashinfo, saddr, sport,
 				       daddr, hnum, dif, sdif);
 	*refcounted = true;
 	if (sk)
 		return sk;
 	*refcounted = false;
 	return __inet_lookup_listener(net, hashinfo, skb, doff, saddr,
 				      sport, daddr, hnum, dif, sdif);
 }

 static inline struct sock *inet_lookup(struct net *net,
 				       struct inet_hashinfo *hashinfo,
 				       struct sk_buff *skb, int doff,
 				       const __be32 saddr, const __be16 sport,
 				       const __be32 daddr, const __be16 dport,
 				       const int dif)
 {
 	struct sock *sk;
 	bool refcounted;

 	sk = __inet_lookup(net, hashinfo, skb, doff, saddr, sport, daddr,
 			   dport, dif, 0, &refcounted);

 	if (sk && !refcounted && !refcount_inc_not_zero(&sk->sk_refcnt))
 		sk = NULL;
 	return sk;
 }

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

 	if (sk)
 		return sk;

 	return __inet_lookup(dev_net(skb_dst(skb)->dev), hashinfo, skb,
 			     doff, iph->saddr, sport,
 			     iph->daddr, dport, inet_iif(skb), sdif,
 			     refcounted);
 }

 u32 inet6_ehashfn(const struct net *net,
 		  const struct in6_addr *laddr, const u16 lport,
 		  const struct in6_addr *faddr, const __be16 fport);

 static inline void sk_daddr_set(struct sock *sk, __be32 addr)
 {
 	sk->sk_daddr = addr; /* alias of inet_daddr */
 #if IS_ENABLED(CONFIG_IPV6)
 	ipv6_addr_set_v4mapped(addr, &sk->sk_v6_daddr);
 #endif
 }

 static inline void sk_rcv_saddr_set(struct sock *sk, __be32 addr)
 {
 	sk->sk_rcv_saddr = addr; /* alias of inet_rcv_saddr */
 #if IS_ENABLED(CONFIG_IPV6)
 	ipv6_addr_set_v4mapped(addr, &sk->sk_v6_rcv_saddr);
 #endif
 }

 int __inet_hash_connect(struct inet_timewait_death_row *death_row,
 			struct sock *sk, u64 port_offset,
 			int (*check_established)(struct inet_timewait_death_row *,
 						 struct sock *, __u16,
 						 struct inet_timewait_sock **));

 int inet_hash_connect(struct inet_timewait_death_row *death_row,
 		      struct sock *sk);
 #endif /* _INET_HASHTABLES_H */
	/* 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.
	*
	* Authors: Lotsa people, from code originally in tcp
	*/

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

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

	/* This is for all connections with a full identity, no wildcards.
	* The 'e' prefix stands for Establish, but we really put all sockets
	* but LISTEN ones.
	*/
	struct inet_ehash_bucket {
	struct hlist_nulls_head chain;
	};

	/* 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
	*/
	#define FASTREUSEPORT_ANY 1
	#define FASTREUSEPORT_STRICT 2

	struct inet_bind_bucket {
	possible_net_t ib_net;
	int l3mdev;
	unsigned short port;
	signed char fastreuse;
	signed char fastreuseport;
	kuid_t fastuid;
	#if IS_ENABLED(CONFIG_IPV6)
	struct in6_addr fast_v6_rcv_saddr;
	#endif
	__be32 fast_rcv_saddr;
	unsigned short fast_sk_family;
	bool fast_ipv6_only;
	struct hlist_node node;
	struct hlist_head owners;
	};

	struct inet_bind2_bucket {
	possible_net_t ib_net;
	int l3mdev;
	unsigned short port;
	#if IS_ENABLED(CONFIG_IPV6)
	unsigned short family;
	#endif
	union {
	#if IS_ENABLED(CONFIG_IPV6)
	struct in6_addr v6_rcv_saddr;
	#endif
	__be32 rcv_saddr;
	};
	/* Node in the bhash2 inet_bind_hashbucket chain */
	struct hlist_node node;
	/* List of sockets hashed to this bucket */
	struct hlist_head owners;
	};

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

	static inline struct net ib2_net(const struct inet_bind2_bucket ib)
	{
	return read_pnet(&ib->ib_net);
	}

	#define inet_bind_bucket_for_each(tb, head) \
	hlist_for_each_entry(tb, 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 all hash buckets :
	* A socket might transition from ESTABLISH to LISTEN state without
	* RCU grace period. A lookup in ehash table needs to handle this case.
	*/
	#define LISTENING_NULLS_BASE (1U << 29)
	struct inet_listen_hashbucket {
	spinlock_t lock;
	struct hlist_nulls_head nulls_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
	*
	*/
	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 kmem_cache *bind_bucket_cachep;
	/* This bind table is hashed by local port */
	struct inet_bind_hashbucket *bhash;
	struct kmem_cache *bind2_bucket_cachep;
	/* This bind table is hashed by local port and sk->sk_rcv_saddr (ipv4)
	* or sk->sk_v6_rcv_saddr (ipv6). This 2nd bind table is used
	* primarily for expediting bind conflict resolution.
	*/
	struct inet_bind_hashbucket *bhash2;
	unsigned int bhash_size;

	/* The 2nd listener table hashed by local port and address */
	unsigned int lhash2_mask;
	struct inet_listen_hashbucket *lhash2;

	bool pernet;
	};

	static inline struct inet_hashinfo tcp_or_dccp_get_hashinfo(const struct sock sk)
	{
	#if IS_ENABLED(CONFIG_IP_DCCP)
	return sk->sk_prot->h.hashinfo ? :
	sock_net(sk)->ipv4.tcp_death_row.hashinfo;
	#else
	return sock_net(sk)->ipv4.tcp_death_row.hashinfo;
	#endif
	}

	static inline struct inet_listen_hashbucket *
	inet_lhash2_bucket(struct inet_hashinfo *h, u32 hash)
	{
	return &h->lhash2[hash & h->lhash2_mask];
	}

	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];
	}

	int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo);

	static inline void inet_hashinfo2_free_mod(struct inet_hashinfo *h)
	{
	kfree(h->lhash2);
	h->lhash2 = NULL;
	}

	static inline void inet_ehash_locks_free(struct inet_hashinfo *hashinfo)
	{
	kvfree(hashinfo->ehash_locks);
	hashinfo->ehash_locks = NULL;
	}

	struct inet_hashinfo inet_pernet_hashinfo_alloc(struct inet_hashinfo hashinfo,
	unsigned int ehash_entries);
	void inet_pernet_hashinfo_free(struct inet_hashinfo *hashinfo);

	struct inet_bind_bucket *
	inet_bind_bucket_create(struct kmem_cache cachep, struct net net,
	struct inet_bind_hashbucket *head,
	const unsigned short snum, int l3mdev);
	void inet_bind_bucket_destroy(struct kmem_cache *cachep,
	struct inet_bind_bucket *tb);

	bool inet_bind_bucket_match(const struct inet_bind_bucket *tb,
	const struct net *net, unsigned short port,
	int l3mdev);

	struct inet_bind2_bucket *
	inet_bind2_bucket_create(struct kmem_cache cachep, struct net net,
	struct inet_bind_hashbucket *head,
	unsigned short port, int l3mdev,
	const struct sock *sk);

	void inet_bind2_bucket_destroy(struct kmem_cache *cachep,
	struct inet_bind2_bucket *tb);

	struct inet_bind2_bucket *
	inet_bind2_bucket_find(const struct inet_bind_hashbucket *head,
	const struct net *net,
	unsigned short port, int l3mdev,
	const struct sock *sk);

	bool inet_bind2_bucket_match_addr_any(const struct inet_bind2_bucket *tb,
	const struct net *net, unsigned short port,
	int l3mdev, const struct sock *sk);

	static inline u32 inet_bhashfn(const struct net *net, const __u16 lport,
	const u32 bhash_size)
	{
	return (lport + net_hash_mix(net)) & (bhash_size - 1);
	}

	static inline struct inet_bind_hashbucket *
	inet_bhashfn_portaddr(const struct inet_hashinfo hinfo, const struct sock sk,
	const struct net *net, unsigned short port)
	{
	u32 hash;

	#if IS_ENABLED(CONFIG_IPV6)
	if (sk->sk_family == AF_INET6)
	hash = ipv6_portaddr_hash(net, &sk->sk_v6_rcv_saddr, port);
	else
	#endif
	hash = ipv4_portaddr_hash(net, sk->sk_rcv_saddr, port);
	return &hinfo->bhash2[hash & (hinfo->bhash_size - 1)];
	}

	struct inet_bind_hashbucket *
	inet_bhash2_addr_any_hashbucket(const struct sock sk, const struct net net, int port);

	/* This should be called whenever a socket's sk_rcv_saddr (ipv4) or
	* sk_v6_rcv_saddr (ipv6) changes after it has been binded. The socket's
	* rcv_saddr field should already have been updated when this is called.
	*/
	int inet_bhash2_update_saddr(struct inet_bind_hashbucket prev_saddr, struct sock sk);

	void inet_bind_hash(struct sock sk, struct inet_bind_bucket tb,
	struct inet_bind2_bucket *tb2, unsigned short port);

	/* Caller must disable local BH processing. */
	int __inet_inherit_port(const struct sock sk, struct sock child);

	void inet_put_port(struct sock *sk);

	void inet_hashinfo2_init(struct inet_hashinfo h, const char name,
	unsigned long numentries, int scale,
	unsigned long low_limit,
	unsigned long high_limit);
	int inet_hashinfo2_init_mod(struct inet_hashinfo *h);

	bool inet_ehash_insert(struct sock sk, struct sock osk, bool *found_dup_sk);
	bool inet_ehash_nolisten(struct sock sk, struct sock osk,
	bool *found_dup_sk);
	int __inet_hash(struct sock sk, struct sock osk);
	int inet_hash(struct sock *sk);
	void inet_unhash(struct sock *sk);

	struct sock __inet_lookup_listener(struct net net,
	struct inet_hashinfo *hashinfo,
	struct sk_buff *skb, int doff,
	const __be32 saddr, const __be16 sport,
	const __be32 daddr,
	const unsigned short hnum,
	const int dif, const int sdif);

	static inline struct sock inet_lookup_listener(struct net net,
	struct inet_hashinfo *hashinfo,
	struct sk_buff *skb, int doff,
	__be32 saddr, __be16 sport,
	__be32 daddr, __be16 dport, int dif, int sdif)
	{
	return __inet_lookup_listener(net, hashinfo, skb, doff, saddr, sport,
	daddr, ntohs(dport), dif, sdif);
	}

	/* 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.
	*/
	#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

	#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 */

	static inline bool inet_match(struct net net, const struct sock sk,
	const __addrpair cookie, const __portpair ports,
	int dif, int sdif)
	{
	if (!net_eq(sock_net(sk), net) \|\|
	sk->sk_portpair != ports \|\|
	sk->sk_addrpair != cookie)
	return false;

	/* READ_ONCE() paired with WRITE_ONCE() in sock_bindtoindex_locked() */
	return inet_sk_bound_dev_eq(net, READ_ONCE(sk->sk_bound_dev_if), dif,
	sdif);
	}

	/* Sockets in TCP_CLOSE state are _always_ taken out of the hash, so we need
	* not check it for lookups anymore, thanks Alexey. -DaveM
	*/
	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, const int sdif);

	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, 0);
	}

	static inline struct sock __inet_lookup(struct net net,
	struct inet_hashinfo *hashinfo,
	struct sk_buff *skb, int doff,
	const __be32 saddr, const __be16 sport,
	const __be32 daddr, const __be16 dport,
	const int dif, const int sdif,
	bool *refcounted)
	{
	u16 hnum = ntohs(dport);
	struct sock *sk;

	sk = __inet_lookup_established(net, hashinfo, saddr, sport,
	daddr, hnum, dif, sdif);
	*refcounted = true;
	if (sk)
	return sk;
	*refcounted = false;
	return __inet_lookup_listener(net, hashinfo, skb, doff, saddr,
	sport, daddr, hnum, dif, sdif);
	}

	static inline struct sock inet_lookup(struct net net,
	struct inet_hashinfo *hashinfo,
	struct sk_buff *skb, int doff,
	const __be32 saddr, const __be16 sport,
	const __be32 daddr, const __be16 dport,
	const int dif)
	{
	struct sock *sk;
	bool refcounted;

	sk = __inet_lookup(net, hashinfo, skb, doff, saddr, sport, daddr,
	dport, dif, 0, &refcounted);

	if (sk && !refcounted && !refcount_inc_not_zero(&sk->sk_refcnt))
	sk = NULL;
	return sk;
	}

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

	if (sk)
	return sk;

	return __inet_lookup(dev_net(skb_dst(skb)->dev), hashinfo, skb,
	doff, iph->saddr, sport,
	iph->daddr, dport, inet_iif(skb), sdif,
	refcounted);
	}

	u32 inet6_ehashfn(const struct net *net,
	const struct in6_addr *laddr, const u16 lport,
	const struct in6_addr *faddr, const __be16 fport);

	static inline void sk_daddr_set(struct sock *sk, __be32 addr)
	{
	sk->sk_daddr = addr; /* alias of inet_daddr */
	#if IS_ENABLED(CONFIG_IPV6)
	ipv6_addr_set_v4mapped(addr, &sk->sk_v6_daddr);
	#endif
	}

	static inline void sk_rcv_saddr_set(struct sock *sk, __be32 addr)
	{
	sk->sk_rcv_saddr = addr; /* alias of inet_rcv_saddr */
	#if IS_ENABLED(CONFIG_IPV6)
	ipv6_addr_set_v4mapped(addr, &sk->sk_v6_rcv_saddr);
	#endif
	}

	int __inet_hash_connect(struct inet_timewait_death_row *death_row,
	struct sock *sk, u64 port_offset,
	int (check_established)(struct inet_timewait_death_row ,
	struct sock *, __u16,
	struct inet_timewait_sock **));

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