- 根目录:
- include
- net
- inet_hashtables.h
/*
* 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 <linux/vmalloc.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 <asm/atomic.h>
#include <asm/byteorder.h>
/* This is for all connections with a full identity, no wildcards.
* One chain is dedicated to TIME_WAIT sockets.
* I'll experiment with dynamic table growth later.
*/
struct inet_ehash_bucket {
struct hlist_nulls_head chain;
struct hlist_nulls_head twchain;
};
/* 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 {
#ifdef CONFIG_NET_NS
struct net *ib_net;
#endif
unsigned short port;
signed short fastreuse;
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, pos, head) \
hlist_for_each_entry(tb, pos, 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 listening
* hash table, or we might find a socket that was closed and
* reallocated/inserted into established hash table
*/
#define LISTENING_NULLS_BASE (1U << 29)
struct inet_listen_hashbucket {
spinlock_t lock;
struct hlist_nulls_head 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
*
* TIME_WAIT sockets use a separate chain (twchain).
*/
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;
atomic_t bsockets;
};
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];
}
static inline int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo)
{
unsigned int i, size = 256;
#if defined(CONFIG_PROVE_LOCKING)
unsigned int nr_pcpus = 2;
#else
unsigned int nr_pcpus = num_possible_cpus();
#endif
if (nr_pcpus >= 4)
size = 512;
if (nr_pcpus >= 8)
size = 1024;
if (nr_pcpus >= 16)
size = 2048;
if (nr_pcpus >= 32)
size = 4096;
if (sizeof(spinlock_t) != 0) {
#ifdef CONFIG_NUMA
if (size * sizeof(spinlock_t) > PAGE_SIZE)
hashinfo->ehash_locks = vmalloc(size * sizeof(spinlock_t));
else
#endif
hashinfo->ehash_locks = kmalloc(size * sizeof(spinlock_t),
GFP_KERNEL);
if (!hashinfo->ehash_locks)
return ENOMEM;
for (i = 0; i < size; i++)
spin_lock_init(&hashinfo->ehash_locks[i]);
}
hashinfo->ehash_locks_mask = size - 1;
return 0;
}
static inline void inet_ehash_locks_free(struct inet_hashinfo *hashinfo)
{
if (hashinfo->ehash_locks) {
#ifdef CONFIG_NUMA
unsigned int size = (hashinfo->ehash_locks_mask + 1) *
sizeof(spinlock_t);
if (size > PAGE_SIZE)
vfree(hashinfo->ehash_locks);
else
#endif
kfree(hashinfo->ehash_locks);
hashinfo->ehash_locks = NULL;
}
}
extern struct inet_bind_bucket *
inet_bind_bucket_create(struct kmem_cache *cachep,
struct net *net,
struct inet_bind_hashbucket *head,
const unsigned short snum);
extern void inet_bind_bucket_destroy(struct kmem_cache *cachep,
struct inet_bind_bucket *tb);
static inline int inet_bhashfn(struct net *net,
const __u16 lport, const int bhash_size)
{
return (lport + net_hash_mix(net)) & (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(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. */
extern int __inet_inherit_port(struct sock *sk, struct sock *child);
extern void inet_put_port(struct sock *sk);
void inet_hashinfo_init(struct inet_hashinfo *h);
extern int __inet_hash_nolisten(struct sock *sk, struct inet_timewait_sock *tw);
extern void inet_hash(struct sock *sk);
extern void inet_unhash(struct sock *sk);
extern struct sock *__inet_lookup_listener(struct net *net,
struct inet_hashinfo *hashinfo,
const __be32 daddr,
const unsigned short hnum,
const int dif);
static inline struct sock *inet_lookup_listener(struct net *net,
struct inet_hashinfo *hashinfo,
__be32 daddr, __be16 dport, int dif)
{
return __inet_lookup_listener(net, hashinfo, 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.
*/
typedef __u32 __bitwise __portpair;
#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)
typedef __u64 __bitwise __addrpair;
#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, __hash, __cookie, __saddr, __daddr, __ports, __dif)\
(((__sk)->sk_hash == (__hash)) && net_eq(sock_net(__sk), (__net)) && \
((*((__addrpair *)&(inet_sk(__sk)->inet_daddr))) == (__cookie)) && \
((*((__portpair *)&(inet_sk(__sk)->inet_dport))) == (__ports)) && \
(!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
#define INET_TW_MATCH(__sk, __net, __hash, __cookie, __saddr, __daddr, __ports, __dif)\
(((__sk)->sk_hash == (__hash)) && net_eq(sock_net(__sk), (__net)) && \
((*((__addrpair *)&(inet_twsk(__sk)->tw_daddr))) == (__cookie)) && \
((*((__portpair *)&(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, __net, __hash, __cookie, __saddr, __daddr, __ports, __dif) \
(((__sk)->sk_hash == (__hash)) && net_eq(sock_net(__sk), (__net)) && \
(inet_sk(__sk)->inet_daddr == (__saddr)) && \
(inet_sk(__sk)->inet_rcv_saddr == (__daddr)) && \
((*((__portpair *)&(inet_sk(__sk)->inet_dport))) == (__ports)) && \
(!((__sk)->sk_bound_dev_if) || ((__sk)->sk_bound_dev_if == (__dif))))
#define INET_TW_MATCH(__sk, __net, __hash,__cookie, __saddr, __daddr, __ports, __dif) \
(((__sk)->sk_hash == (__hash)) && net_eq(sock_net(__sk), (__net)) && \
(inet_twsk(__sk)->tw_daddr == (__saddr)) && \
(inet_twsk(__sk)->tw_rcv_saddr == (__daddr)) && \
((*((__portpair *)&(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.
*/
extern 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,
const __be32 saddr, const __be16 sport,
const __be32 daddr, const __be16 dport,
const int dif)
{
u16 hnum = ntohs(dport);
struct sock *sk = __inet_lookup_established(net, hashinfo,
saddr, sport, daddr, hnum, dif);
return sk ? : __inet_lookup_listener(net, hashinfo, daddr, hnum, dif);
}
static inline struct sock *inet_lookup(struct net *net,
struct inet_hashinfo *hashinfo,
const __be32 saddr, const __be16 sport,
const __be32 daddr, const __be16 dport,
const int dif)
{
struct sock *sk;
local_bh_disable();
sk = __inet_lookup(net, hashinfo, saddr, sport, daddr, dport, dif);
local_bh_enable();
return sk;
}
static inline struct sock *__inet_lookup_skb(struct inet_hashinfo *hashinfo,
struct sk_buff *skb,
const __be16 sport,
const __be16 dport)
{
struct sock *sk;
const struct iphdr *iph = ip_hdr(skb);
if (unlikely(sk = skb_steal_sock(skb)))
return sk;
else
return __inet_lookup(dev_net(skb_dst(skb)->dev), hashinfo,
iph->saddr, sport,
iph->daddr, dport, inet_iif(skb));
}
extern 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 (*hash)(struct sock *sk, struct inet_timewait_sock *twp));
extern int inet_hash_connect(struct inet_timewait_death_row *death_row,
struct sock *sk);
#endif /* _INET_HASHTABLES_H */