name : 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 bhash2; }; 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; }; 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_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, 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)]; } 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); 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); 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(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(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, 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_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 inet_hashinfo *hashinfo, struct sk_buff *skb, int doff, const __be16 sport, const __be16 dport, const int sdif, bool *refcounted) { struct net *net = dev_net(skb_dst(skb)->dev); 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) return sk; return __inet_lookup(net, hashinfo, skb, doff, iph->saddr, sport, iph->daddr, dport, inet_iif(skb), sdif, refcounted); } 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 */