/* (C) 1999-2001 Paul `Rusty' Russell
* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>:
* - Real stateful connection tracking
* - Modified state transitions table
* - Window scaling support added
* - SACK support added
*
* Willy Tarreau:
* - State table bugfixes
* - More robust state changes
* - Tuning timer parameters
*
* 27 Oct 2004: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
* - genelized Layer 3 protocol part.
*
* Derived from net/ipv4/netfilter/ip_conntrack_proto_tcp.c
*
* version 2.2
*/
#include <linux/types.h>
#include <linux/timer.h>
#include <linux/netfilter.h>
#include <linux/module.h>
#include <linux/in.h>
#include <linux/tcp.h>
#include <linux/spinlock.h>
#include <linux/skbuff.h>
#include <linux/ipv6.h>
#include <net/ip6_checksum.h>
#include <net/tcp.h>
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter_ipv6.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_l4proto.h>
#include <net/netfilter/nf_conntrack_ecache.h>
#if 0
#define DEBUGP printk
#define DEBUGP_VARS
#else
#define DEBUGP(format, args...)
#endif
/* Protects conntrack->proto.tcp */
static DEFINE_RWLOCK(tcp_lock);
/* "Be conservative in what you do,
be liberal in what you accept from others."
If it's non-zero, we mark only out of window RST segments as INVALID. */
static int nf_ct_tcp_be_liberal __read_mostly = 0;
/* If it is set to zero, we disable picking up already established
connections. */
static int nf_ct_tcp_loose __read_mostly = 1;
/* Max number of the retransmitted packets without receiving an (acceptable)
ACK from the destination. If this number is reached, a shorter timer
will be started. */
static int nf_ct_tcp_max_retrans __read_mostly = 3;
/* FIXME: Examine ipfilter's timeouts and conntrack transitions more
closely. They're more complex. --RR */
static const char *tcp_conntrack_names[] = {
"NONE",
"SYN_SENT",
"SYN_RECV",
"ESTABLISHED",
"FIN_WAIT",
"CLOSE_WAIT",
"LAST_ACK",
"TIME_WAIT",
"CLOSE",
"LISTEN"
};
#define SECS * HZ
#define MINS * 60 SECS
#define HOURS * 60 MINS
#define DAYS * 24 HOURS
static unsigned int nf_ct_tcp_timeout_syn_sent __read_mostly