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/* 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	bhash2;	struct rcu_head		rcu;}; struct inet_bind2_bucket {	possible_net_t		ib_net;	int			l3mdev;	unsigned short		port;#if IS_ENABLED(CONFIG_IPV6)	unsigned short		addr_type;	struct in6_addr		v6_rcv_saddr;#define rcv_saddr		v6_rcv_saddr.s6_addr32[3]#else	__be32			rcv_saddr;#endif	/* Node in the bhash2 inet_bind_hashbucket chain */	struct hlist_node	node;	struct hlist_node	bhash_node;	/* List of sockets hashed to this bucket */	struct hlist_head	owners;	signed char		fastreuse;	signed char		fastreuseport;}; 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;} ____cacheline_aligned_in_smp; static inline struct inet_hashinfo *tcp_get_hashinfo(const struct sock *sk){	return sock_net(sk)->ipv4.tcp_death_row.hashinfo;} 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_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 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,			 struct inet_bind_bucket *tb,			 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)];} static inline bool inet_use_hash2_on_bind(const struct sock *sk){#if IS_ENABLED(CONFIG_IPV6)	if (sk->sk_family == AF_INET6) {		if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))			return false; 		if (!ipv6_addr_v4mapped(&sk->sk_v6_rcv_saddr))			return true;	}#endif	return sk->sk_rcv_saddr != htonl(INADDR_ANY);} 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 sock *sk, void *saddr, int family);void inet_bhash2_reset_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); 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);void inet_unhash(struct sock *sk); struct sock *__inet_lookup_listener(const struct net *net,				    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 sk_buff *skb, int doff,						__be32 saddr, __be16 sport,						__be32 daddr, __be16 dport,						int dif, int sdif){	return __inet_lookup_listener(net, 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(const struct net *net, const struct sock *sk,			      const __addrpair cookie, const __portpair ports,			      int dif, int sdif){	if (!net_eq(sock_net(sk), net) ||	    READ_ONCE(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(const struct net *net,				       const __be32 saddr, const __be16 sport,				       const __be32 daddr, const u16 hnum,				       const int dif, const int sdif); typedef u32 (inet_ehashfn_t)(const struct net *net,			      const __be32 laddr, const __u16 lport,			      const __be32 faddr, const __be16 fport); inet_ehashfn_t inet_ehashfn; INDIRECT_CALLABLE_DECLARE(inet_ehashfn_t udp_ehashfn); struct sock *inet_lookup_reuseport(const struct net *net, struct sock *sk,				   struct sk_buff *skb, int doff,				   __be32 saddr, __be16 sport,				   __be32 daddr, unsigned short hnum,				   inet_ehashfn_t *ehashfn); struct sock *inet_lookup_run_sk_lookup(const struct net *net,				       int protocol,				       struct sk_buff *skb, int doff,				       __be32 saddr, __be16 sport,				       __be32 daddr, u16 hnum, const int dif,				       inet_ehashfn_t *ehashfn); static inline struct sock *inet_lookup_established(struct net *net,						   const __be32 saddr, const __be16 sport,						   const __be32 daddr, const __be16 dport,						   const int dif){	return __inet_lookup_established(net, saddr, sport, daddr,					 ntohs(dport), dif, 0);} static inline struct sock *__inet_lookup(struct net *net,					 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, saddr, sport,				       daddr, hnum, dif, sdif);	*refcounted = true;	if (sk)		return sk;	*refcounted = false;	return __inet_lookup_listener(net, skb, doff, saddr,				      sport, daddr, hnum, dif, sdif);} static inline struct sock *inet_lookup(struct net *net,				       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, skb, doff, saddr, sport, daddr,			   dport, dif, 0, &refcounted); 	if (sk && !refcounted && !refcount_inc_not_zero(&sk->sk_refcnt))		sk = NULL;	return sk;} static inlinestruct sock *inet_steal_sock(struct net *net, struct sk_buff *skb, int doff,			     const __be32 saddr, const __be16 sport,			     const __be32 daddr, const __be16 dport,			     bool *refcounted, inet_ehashfn_t *ehashfn){	struct sock *sk, *reuse_sk;	bool prefetched; 	sk = skb_steal_sock(skb, refcounted, &prefetched);	if (!sk)		return NULL; 	if (!prefetched || !sk_fullsock(sk))		return sk; 	if (sk->sk_protocol == IPPROTO_TCP) {		if (sk->sk_state != TCP_LISTEN)			return sk;	} else if (sk->sk_protocol == IPPROTO_UDP) {		if (sk->sk_state != TCP_CLOSE)			return sk;	} else {		return sk;	} 	reuse_sk = inet_lookup_reuseport(net, sk, skb, doff,					 saddr, sport, daddr, ntohs(dport),					 ehashfn);	if (!reuse_sk)		return sk; 	/* We've chosen a new reuseport sock which is never refcounted. This	 * implies that sk also isn't refcounted.	 */	WARN_ON_ONCE(*refcounted); 	return reuse_sk;} static inline struct sock *__inet_lookup_skb(struct sk_buff *skb,					     int doff,					     const __be16 sport,					     const __be16 dport,					     const int sdif,					     bool *refcounted){	struct net *net = skb_dst_dev_net_rcu(skb);	const struct iphdr *iph = ip_hdr(skb);	struct sock *sk; 	sk = inet_steal_sock(net, skb, doff, iph->saddr, sport, iph->daddr, dport,			     refcounted, inet_ehashfn);	if (IS_ERR(sk))		return NULL;	if (sk)

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