| /* |
| * 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/config.h> |
| |
| #include <linux/interrupt.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/route.h> |
| #include <net/sock.h> |
| #include <net/tcp_states.h> |
| |
| #include <asm/atomic.h> |
| #include <asm/byteorder.h> |
| |
| /* This is for all connections with a full identity, no wildcards. |
| * New scheme, half the table is for TIME_WAIT, the other half is |
| * for the rest. I'll experiment with dynamic table growth later. |
| */ |
| struct inet_ehash_bucket { |
| rwlock_t lock; |
| struct hlist_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 { |
| unsigned short port; |
| signed short fastreuse; |
| struct hlist_node node; |
| struct hlist_head owners; |
| }; |
| |
| #define inet_bind_bucket_for_each(tb, node, head) \ |
| hlist_for_each_entry(tb, node, head, node) |
| |
| struct inet_bind_hashbucket { |
| spinlock_t lock; |
| struct hlist_head chain; |
| }; |
| |
| /* 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 |
| * |
| * First half of the table is for sockets not in TIME_WAIT, second half |
| * is for TIME_WAIT sockets only. |
| */ |
| struct inet_ehash_bucket *ehash; |
| |
| /* 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; |
| |
| int bhash_size; |
| unsigned int ehash_size; |
| |
| /* 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 hlist_head listening_hash[INET_LHTABLE_SIZE]; |
| |
| /* 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 |
| * are often dirty. |
| */ |
| rwlock_t lhash_lock ____cacheline_aligned; |
| atomic_t lhash_users; |
| wait_queue_head_t lhash_wait; |
| kmem_cache_t *bind_bucket_cachep; |
| }; |
| |
| static inline unsigned int inet_ehashfn(const __u32 laddr, const __u16 lport, |
| const __u32 faddr, const __u16 fport) |
| { |
| unsigned int h = (laddr ^ lport) ^ (faddr ^ fport); |
| h ^= h >> 16; |
| h ^= h >> 8; |
| return h; |
| } |
| |
| static inline int inet_sk_ehashfn(const struct sock *sk) |
| { |
| const struct inet_sock *inet = inet_sk(sk); |
| const __u32 laddr = inet->rcv_saddr; |
| const __u16 lport = inet->num; |
| const __u32 faddr = inet->daddr; |
| const __u16 fport = inet->dport; |
| |
| return inet_ehashfn(laddr, lport, faddr, fport); |
| } |
| |
| static inline struct inet_ehash_bucket *inet_ehash_bucket( |
| struct inet_hashinfo *hashinfo, |
| unsigned int hash) |
| { |
| return &hashinfo->ehash[hash & (hashinfo->ehash_size - 1)]; |
| } |
| |
| extern struct inet_bind_bucket * |
| inet_bind_bucket_create(kmem_cache_t *cachep, |
| struct inet_bind_hashbucket *head, |
| const unsigned short snum); |
| extern void inet_bind_bucket_destroy(kmem_cache_t *cachep, |
| struct inet_bind_bucket *tb); |
| |
| static inline int inet_bhashfn(const __u16 lport, const int bhash_size) |
| { |
| return lport & (bhash_size - 1); |
| } |
| |
| extern 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 int inet_lhashfn(const unsigned short num) |
| { |
| return num & (INET_LHTABLE_SIZE - 1); |
| } |
| |
| static inline int inet_sk_listen_hashfn(const struct sock *sk) |
| { |
| return inet_lhashfn(inet_sk(sk)->num); |
| } |
| |
| /* Caller must disable local BH processing. */ |
| static inline void __inet_inherit_port(struct inet_hashinfo *table, |
| struct sock *sk, struct sock *child) |
| { |
| const int bhash = inet_bhashfn(inet_sk(child)->num, table->bhash_size); |
| struct inet_bind_hashbucket *head = &table->bhash[bhash]; |
| struct inet_bind_bucket *tb; |
| |
| spin_lock(&head->lock); |
| tb = inet_csk(sk)->icsk_bind_hash; |
| sk_add_bind_node(child, &tb->owners); |
| inet_csk(child)->icsk_bind_hash = tb; |
| spin_unlock(&head->lock); |
| } |
| |
| static inline void inet_inherit_port(struct inet_hashinfo *table, |
| struct sock *sk, struct sock *child) |
| { |
| local_bh_disable(); |
| __inet_inherit_port(table, sk, child); |
| local_bh_enable(); |
| } |
| |
| extern void inet_put_port(struct inet_hashinfo *table, struct sock *sk); |
| |
| extern void inet_listen_wlock(struct inet_hashinfo *hashinfo); |
| |
| /* |
| * - We may sleep inside this lock. |
| * - If sleeping is not required (or called from BH), |
| * use plain read_(un)lock(&inet_hashinfo.lhash_lock). |
| */ |
| static inline void inet_listen_lock(struct inet_hashinfo *hashinfo) |
| { |
| /* read_lock synchronizes to candidates to writers */ |
| read_lock(&hashinfo->lhash_lock); |
| atomic_inc(&hashinfo->lhash_users); |
| read_unlock(&hashinfo->lhash_lock); |
| } |
| |
| static inline void inet_listen_unlock(struct inet_hashinfo *hashinfo) |
| { |
| if (atomic_dec_and_test(&hashinfo->lhash_users)) |
| wake_up(&hashinfo->lhash_wait); |
| } |
| |
| static inline void __inet_hash(struct inet_hashinfo *hashinfo, |
| struct sock *sk, const int listen_possible) |
| { |
| struct hlist_head *list; |
| rwlock_t *lock; |
| |
| BUG_TRAP(sk_unhashed(sk)); |
| if (listen_possible && sk->sk_state == TCP_LISTEN) { |
| list = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)]; |
| lock = &hashinfo->lhash_lock; |
| inet_listen_wlock(hashinfo); |
| } else { |
| struct inet_ehash_bucket *head; |
| sk->sk_hash = inet_sk_ehashfn(sk); |
| head = inet_ehash_bucket(hashinfo, sk->sk_hash); |
| list = &head->chain; |
| lock = &head->lock; |
| write_lock(lock); |
| } |
| __sk_add_node(sk, list); |
| sock_prot_inc_use(sk->sk_prot); |
| write_unlock(lock); |
| if (listen_possible && sk->sk_state == TCP_LISTEN) |
| wake_up(&hashinfo->lhash_wait); |
| } |
| |
| static inline void inet_hash(struct inet_hashinfo *hashinfo, struct sock *sk) |
| { |
| if (sk->sk_state != TCP_CLOSE) { |
| local_bh_disable(); |
| __inet_hash(hashinfo, sk, 1); |
| local_bh_enable(); |
| } |
| } |
| |
| static inline void inet_unhash(struct inet_hashinfo *hashinfo, struct sock *sk) |
| { |
| rwlock_t *lock; |
| |
| if (sk_unhashed(sk)) |
| goto out; |
| |
| if (sk->sk_state == TCP_LISTEN) { |
| local_bh_disable(); |
| inet_listen_wlock(hashinfo); |
| lock = &hashinfo->lhash_lock; |
| } else { |
| lock = &inet_ehash_bucket(hashinfo, sk->sk_hash)->lock; |
| write_lock_bh(lock); |
| } |
| |
| if (__sk_del_node_init(sk)) |
| sock_prot_dec_use(sk->sk_prot); |
| write_unlock_bh(lock); |
| out: |
| if (sk->sk_state == TCP_LISTEN) |
| wake_up(&hashinfo->lhash_wait); |
| } |
| |
| static inline int inet_iif(const struct sk_buff *skb) |
| { |
| return ((struct rtable *)skb->dst)->rt_iif; |
| } |
| |
| extern struct sock *__inet_lookup_listener(const struct hlist_head *head, |
| const u32 daddr, |
| const unsigned short hnum, |
| const int dif); |
| |
| /* Optimize the common listener case. */ |
| static inline struct sock * |
| inet_lookup_listener(struct inet_hashinfo *hashinfo, |
| const u32 daddr, |
| const unsigned short hnum, const int dif) |
| { |
| struct sock *sk = NULL; |
| const struct hlist_head *head; |
| |
| read_lock(&hashinfo->lhash_lock); |
| head = &hashinfo->listening_hash[inet_lhashfn(hnum)]; |
| if (!hlist_empty(head)) { |
| const struct inet_sock *inet = inet_sk((sk = __sk_head(head))); |
| |
| if (inet->num == hnum && !sk->sk_node.next && |
| (!inet->rcv_saddr || inet->rcv_saddr == daddr) && |
| (sk->sk_family == PF_INET || !ipv6_only_sock(sk)) && |
| !sk->sk_bound_dev_if) |
| goto sherry_cache; |
| sk = __inet_lookup_listener(head, daddr, hnum, dif); |
| } |
| if (sk) { |
| sherry_cache: |
| sock_hold(sk); |
| } |
| read_unlock(&hashinfo->lhash_lock); |
| return sk; |
| } |
| |
| /* Socket demux engine toys. */ |
| #ifdef __BIG_ENDIAN |
| #define INET_COMBINED_PORTS(__sport, __dport) \ |
| (((__u32)(__sport) << 16) | (__u32)(__dport)) |
| #else /* __LITTLE_ENDIAN */ |
| #define INET_COMBINED_PORTS(__sport, __dport) \ |
| (((__u32)(__dport) << 16) | (__u32)(__sport)) |
| #endif |
| |
| #if (BITS_PER_LONG == 64) |
| #ifdef __BIG_ENDIAN |
| #define INET_ADDR_COOKIE(__name, __saddr, __daddr) \ |
| const __u64 __name = (((__u64)(__saddr)) << 32) | ((__u64)(__daddr)); |
| #else /* __LITTLE_ENDIAN */ |
| #define INET_ADDR_COOKIE(__name, __saddr, __daddr) \ |
| const __u64 __name = (((__u64)(__daddr)) << 32) | ((__u64)(__saddr)); |
| #endif /* __BIG_ENDIAN */ |
| #define INET_MATCH(__sk, __hash, __cookie, __saddr, __daddr, __ports, __dif)\ |
| (((__sk)->sk_hash == (__hash)) && \ |
| ((*((__u64 *)&(inet_sk(__sk)->daddr))) == (__cookie)) && \ |
| ((*((__u32 *)&(inet_sk(__sk)->dport))) == (__ports)) && \ |
| (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) |
| #define INET_TW_MATCH(__sk, __hash, __cookie, __saddr, __daddr, __ports, __dif)\ |
| (((__sk)->sk_hash == (__hash)) && \ |
| ((*((__u64 *)&(inet_twsk(__sk)->tw_daddr))) == (__cookie)) && \ |
| ((*((__u32 *)&(inet_twsk(__sk)->tw_dport))) == (__ports)) && \ |
| (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) |
| #else /* 32-bit arch */ |
| #define INET_ADDR_COOKIE(__name, __saddr, __daddr) |
| #define INET_MATCH(__sk, __hash, __cookie, __saddr, __daddr, __ports, __dif) \ |
| (((__sk)->sk_hash == (__hash)) && \ |
| (inet_sk(__sk)->daddr == (__saddr)) && \ |
| (inet_sk(__sk)->rcv_saddr == (__daddr)) && \ |
| ((*((__u32 *)&(inet_sk(__sk)->dport))) == (__ports)) && \ |
| (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) |
| #define INET_TW_MATCH(__sk, __hash,__cookie, __saddr, __daddr, __ports, __dif) \ |
| (((__sk)->sk_hash == (__hash)) && \ |
| (inet_twsk(__sk)->tw_daddr == (__saddr)) && \ |
| (inet_twsk(__sk)->tw_rcv_saddr == (__daddr)) && \ |
| ((*((__u32 *)&(inet_twsk(__sk)->tw_dport))) == (__ports)) && \ |
| (!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif)))) |
| #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 |
| * |
| * Local BH must be disabled here. |
| */ |
| static inline struct sock * |
| __inet_lookup_established(struct inet_hashinfo *hashinfo, |
| const u32 saddr, const u16 sport, |
| const u32 daddr, const u16 hnum, |
| const int dif) |
| { |
| INET_ADDR_COOKIE(acookie, saddr, daddr) |
| const __u32 ports = INET_COMBINED_PORTS(sport, hnum); |
| struct sock *sk; |
| const struct hlist_node *node; |
| /* Optimize here for direct hit, only listening connections can |
| * have wildcards anyways. |
| */ |
| unsigned int hash = inet_ehashfn(daddr, hnum, saddr, sport); |
| struct inet_ehash_bucket *head = inet_ehash_bucket(hashinfo, hash); |
| |
| prefetch(head->chain.first); |
| read_lock(&head->lock); |
| sk_for_each(sk, node, &head->chain) { |
| if (INET_MATCH(sk, hash, acookie, saddr, daddr, ports, dif)) |
| goto hit; /* You sunk my battleship! */ |
| } |
| |
| /* Must check for a TIME_WAIT'er before going to listener hash. */ |
| sk_for_each(sk, node, &(head + hashinfo->ehash_size)->chain) { |
| if (INET_TW_MATCH(sk, hash, acookie, saddr, daddr, ports, dif)) |
| goto hit; |
| } |
| sk = NULL; |
| out: |
| read_unlock(&head->lock); |
| return sk; |
| hit: |
| sock_hold(sk); |
| goto out; |
| } |
| |
| static inline struct sock *__inet_lookup(struct inet_hashinfo *hashinfo, |
| const u32 saddr, const u16 sport, |
| const u32 daddr, const u16 hnum, |
| const int dif) |
| { |
| struct sock *sk = __inet_lookup_established(hashinfo, saddr, sport, daddr, |
| hnum, dif); |
| return sk ? : inet_lookup_listener(hashinfo, daddr, hnum, dif); |
| } |
| |
| static inline struct sock *inet_lookup(struct inet_hashinfo *hashinfo, |
| const u32 saddr, const u16 sport, |
| const u32 daddr, const u16 dport, |
| const int dif) |
| { |
| struct sock *sk; |
| |
| local_bh_disable(); |
| sk = __inet_lookup(hashinfo, saddr, sport, daddr, ntohs(dport), dif); |
| local_bh_enable(); |
| |
| return sk; |
| } |
| #endif /* _INET_HASHTABLES_H */ |