| /* |
| * 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 |
| * |
| * 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. |
| */ |
| |
| #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/sock.h> |
| #include <net/route.h> |
| #include <net/tcp_states.h> |
| #include <net/netns/hash.h> |
| |
| #include <linux/atomic.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 |
| */ |
| struct inet_bind_bucket { |
| possible_net_t ib_net; |
| unsigned short port; |
| signed char fastreuse; |
| signed char fastreuseport; |
| kuid_t fastuid; |
| int num_owners; |
| struct hlist_node node; |
| struct hlist_head owners; |
| }; |
| |
| static inline struct net *ib_net(struct inet_bind_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; |
| union { |
| struct hlist_head head; |
| 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 inet_bind_hashbucket *bhash; |
| |
| unsigned int bhash_size; |
| /* 4 bytes hole on 64 bit */ |
| |
| struct kmem_cache *bind_bucket_cachep; |
| |
| /* All the above members are written once at bootup and |
| * never written again _or_ are predominantly read-access. |
| * |
| * Now align to a new cache line as all the following members |
| * might be often dirty. |
| */ |
| /* All sockets in TCP_LISTEN state will be in here. This is the only |
| * table where wildcard'd TCP sockets can exist. Hash function here |
| * is just local port number. |
| */ |
| struct inet_listen_hashbucket listening_hash[INET_LHTABLE_SIZE] |
| ____cacheline_aligned_in_smp; |
| }; |
| |
| 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_bind_bucket * |
| inet_bind_bucket_create(struct kmem_cache *cachep, struct net *net, |
| struct inet_bind_hashbucket *head, |
| const unsigned short snum); |
| void inet_bind_bucket_destroy(struct kmem_cache *cachep, |
| struct inet_bind_bucket *tb); |
| |
| 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); |
| } |
| |
| void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb, |
| const unsigned short snum); |
| |
| /* These can have wildcards, don't try too hard. */ |
| static inline u32 inet_lhashfn(const struct net *net, const unsigned short num) |
| { |
| return (num + net_hash_mix(net)) & (INET_LHTABLE_SIZE - 1); |
| } |
| |
| static inline int inet_sk_listen_hashfn(const struct sock *sk) |
| { |
| return inet_lhashfn(sock_net(sk), inet_sk(sk)->inet_num); |
| } |
| |
| /* 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_hashinfo_init(struct inet_hashinfo *h); |
| |
| bool inet_ehash_insert(struct sock *sk, struct sock *osk); |
| bool inet_ehash_nolisten(struct sock *sk, struct sock *osk); |
| int __inet_hash(struct sock *sk, struct sock *osk, |
| int (*saddr_same)(const struct sock *sk1, |
| const struct sock *sk2, |
| bool match_wildcard)); |
| 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); |
| |
| 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) |
| { |
| return __inet_lookup_listener(net, hashinfo, skb, doff, saddr, sport, |
| daddr, ntohs(dport), dif); |
| } |
| |
| /* 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 |
| |
| #if (BITS_PER_LONG == 64) |
| #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 */ |
| #define INET_MATCH(__sk, __net, __cookie, __saddr, __daddr, __ports, __dif) \ |
| (((__sk)->sk_portpair == (__ports)) && \ |
| ((__sk)->sk_addrpair == (__cookie)) && \ |
| (!(__sk)->sk_bound_dev_if || \ |
| ((__sk)->sk_bound_dev_if == (__dif))) && \ |
| net_eq(sock_net(__sk), (__net))) |
| #else /* 32-bit arch */ |
| #define INET_ADDR_COOKIE(__name, __saddr, __daddr) \ |
| const int __name __deprecated __attribute__((unused)) |
| |
| #define INET_MATCH(__sk, __net, __cookie, __saddr, __daddr, __ports, __dif) \ |
| (((__sk)->sk_portpair == (__ports)) && \ |
| ((__sk)->sk_daddr == (__saddr)) && \ |
| ((__sk)->sk_rcv_saddr == (__daddr)) && \ |
| (!(__sk)->sk_bound_dev_if || \ |
| ((__sk)->sk_bound_dev_if == (__dif))) && \ |
| net_eq(sock_net(__sk), (__net))) |
| #endif /* 64-bit arch */ |
| |
| /* 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); |
| |
| 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); |
| } |
| |
| 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, |
| bool *refcounted) |
| { |
| u16 hnum = ntohs(dport); |
| struct sock *sk; |
| |
| sk = __inet_lookup_established(net, hashinfo, saddr, sport, |
| daddr, hnum, dif); |
| *refcounted = true; |
| if (sk) |
| return sk; |
| *refcounted = false; |
| return __inet_lookup_listener(net, hashinfo, skb, doff, saddr, |
| sport, daddr, hnum, dif); |
| } |
| |
| 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, &refcounted); |
| |
| if (sk && !refcounted && !atomic_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, |
| bool *refcounted) |
| { |
| struct sock *sk = skb_steal_sock(skb); |
| const struct iphdr *iph = ip_hdr(skb); |
| |
| *refcounted = true; |
| 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), |
| refcounted); |
| } |
| |
| u32 sk_ehashfn(const struct sock *sk); |
| 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, u32 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 */ |