2005-08-09 20:59:20 -06:00
|
|
|
/*
|
|
|
|
* 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
|
|
|
|
|
2005-08-09 21:07:13 -06:00
|
|
|
#include <linux/interrupt.h>
|
2005-08-09 21:00:51 -06:00
|
|
|
#include <linux/ip.h>
|
|
|
|
#include <linux/list.h>
|
|
|
|
#include <linux/slab.h>
|
|
|
|
#include <linux/spinlock.h>
|
2005-08-09 20:59:20 -06:00
|
|
|
#include <linux/types.h>
|
|
|
|
|
2005-08-09 21:07:13 -06:00
|
|
|
#include <net/sock.h>
|
|
|
|
|
2005-08-09 21:00:51 -06:00
|
|
|
/* 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;
|
|
|
|
} __attribute__((__aligned__(8)));
|
|
|
|
|
|
|
|
/* 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;
|
|
|
|
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;
|
|
|
|
spinlock_t portalloc_lock;
|
2005-08-09 21:07:13 -06:00
|
|
|
kmem_cache_t *bind_bucket_cachep;
|
2005-08-09 21:00:51 -06:00
|
|
|
};
|
|
|
|
|
2005-08-09 20:59:20 -06:00
|
|
|
static inline int inet_ehashfn(const __u32 laddr, const __u16 lport,
|
|
|
|
const __u32 faddr, const __u16 fport,
|
|
|
|
const int ehash_size)
|
|
|
|
{
|
|
|
|
int h = (laddr ^ lport) ^ (faddr ^ fport);
|
|
|
|
h ^= h >> 16;
|
|
|
|
h ^= h >> 8;
|
|
|
|
return h & (ehash_size - 1);
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline int inet_sk_ehashfn(const struct sock *sk, const int ehash_size)
|
|
|
|
{
|
|
|
|
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, ehash_size);
|
|
|
|
}
|
|
|
|
|
2005-08-09 21:00:51 -06:00
|
|
|
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);
|
|
|
|
}
|
|
|
|
|
2005-08-09 21:07:13 -06:00
|
|
|
extern void inet_bind_hash(struct sock *sk, struct inet_bind_bucket *tb,
|
|
|
|
const unsigned short snum);
|
|
|
|
|
2005-08-09 21:00:51 -06:00
|
|
|
/* 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);
|
|
|
|
}
|
|
|
|
|
2005-08-09 21:07:13 -06:00
|
|
|
/* 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_sk(sk)->bind_hash;
|
|
|
|
sk_add_bind_node(child, &tb->owners);
|
|
|
|
inet_sk(child)->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);
|
|
|
|
|
2005-08-09 20:59:20 -06:00
|
|
|
#endif /* _INET_HASHTABLES_H */
|