ip_conntrack.h

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#ifndef _IP_CONNTRACK_H
#define _IP_CONNTRACK_H
/* Connection state tracking for netfilter.  This is separated from,
   but required by, the NAT layer; it can also be used by an iptables
   extension. */
enum ip_conntrack_info
{
	/* Part of an established connection (either direction). */
	IP_CT_ESTABLISHED,

	/* Like NEW, but related to an existing connection, or ICMP error
	   (in either direction). */
	IP_CT_RELATED,

	/* Started a new connection to track (only
           IP_CT_DIR_ORIGINAL); may be a retransmission. */
	IP_CT_NEW,

	/* >= this indicates reply direction */
	IP_CT_IS_REPLY,

	/* Number of distinct IP_CT types (no NEW in reply dirn). */
	IP_CT_NUMBER = IP_CT_IS_REPLY * 2 - 1
};

/* Bitset representing status of connection. */
enum ip_conntrack_status {
	/* It's an expected connection: bit 0 set.  This bit never changed */
	IPS_EXPECTED_BIT = 0,
	IPS_EXPECTED = (1 << IPS_EXPECTED_BIT),

	/* We've seen packets both ways: bit 1 set.  Can be set, not unset. */
	IPS_SEEN_REPLY_BIT = 1,
	IPS_SEEN_REPLY = (1 << IPS_SEEN_REPLY_BIT),

	/* Conntrack should never be early-expired. */
	IPS_ASSURED_BIT = 2,
	IPS_ASSURED = (1 << IPS_ASSURED_BIT),

	/* Connection is confirmed: originating packet has left box */
	IPS_CONFIRMED_BIT = 3,
	IPS_CONFIRMED = (1 << IPS_CONFIRMED_BIT),

	/* Connection needs src nat in orig dir.  This bit never changed. */
	IPS_SRC_NAT_BIT = 4,
	IPS_SRC_NAT = (1 << IPS_SRC_NAT_BIT),

	/* Connection needs dst nat in orig dir.  This bit never changed. */
	IPS_DST_NAT_BIT = 5,
	IPS_DST_NAT = (1 << IPS_DST_NAT_BIT),

	/* Both together. */
	IPS_NAT_MASK = (IPS_DST_NAT | IPS_SRC_NAT),

	/* Connection needs TCP sequence adjusted. */
	IPS_SEQ_ADJUST_BIT = 6,
	IPS_SEQ_ADJUST = (1 << IPS_SEQ_ADJUST_BIT),

	/* NAT initialization bits. */
	IPS_SRC_NAT_DONE_BIT = 7,
	IPS_SRC_NAT_DONE = (1 << IPS_SRC_NAT_DONE_BIT),

	IPS_DST_NAT_DONE_BIT = 8,
	IPS_DST_NAT_DONE = (1 << IPS_DST_NAT_DONE_BIT),

	/* Both together */
	IPS_NAT_DONE_MASK = (IPS_DST_NAT_DONE | IPS_SRC_NAT_DONE),

	/* Connection is dying (removed from lists), can not be unset. */
	IPS_DYING_BIT = 9,
	IPS_DYING = (1 << IPS_DYING_BIT),
};

/* Connection tracking event bits */
enum ip_conntrack_events
{
	/* New conntrack */
	IPCT_NEW_BIT = 0,
	IPCT_NEW = (1 << IPCT_NEW_BIT),

	/* Expected connection */
	IPCT_RELATED_BIT = 1,
	IPCT_RELATED = (1 << IPCT_RELATED_BIT),

	/* Destroyed conntrack */
	IPCT_DESTROY_BIT = 2,
	IPCT_DESTROY = (1 << IPCT_DESTROY_BIT),

	/* Timer has been refreshed */
	IPCT_REFRESH_BIT = 3,
	IPCT_REFRESH = (1 << IPCT_REFRESH_BIT),

	/* Status has changed */
	IPCT_STATUS_BIT = 4,
	IPCT_STATUS = (1 << IPCT_STATUS_BIT),

	/* Update of protocol info */
	IPCT_PROTOINFO_BIT = 5,
	IPCT_PROTOINFO = (1 << IPCT_PROTOINFO_BIT),

	/* Volatile protocol info */
	IPCT_PROTOINFO_VOLATILE_BIT = 6,
	IPCT_PROTOINFO_VOLATILE = (1 << IPCT_PROTOINFO_VOLATILE_BIT),

	/* New helper for conntrack */
	IPCT_HELPER_BIT = 7,
	IPCT_HELPER = (1 << IPCT_HELPER_BIT),

	/* Update of helper info */
	IPCT_HELPINFO_BIT = 8,
	IPCT_HELPINFO = (1 << IPCT_HELPINFO_BIT),

	/* Volatile helper info */
	IPCT_HELPINFO_VOLATILE_BIT = 9,
	IPCT_HELPINFO_VOLATILE = (1 << IPCT_HELPINFO_VOLATILE_BIT),

	/* NAT info */
	IPCT_NATINFO_BIT = 10,
	IPCT_NATINFO = (1 << IPCT_NATINFO_BIT),

	/* Counter highest bit has been set */
	IPCT_COUNTER_FILLING_BIT = 11,
	IPCT_COUNTER_FILLING = (1 << IPCT_COUNTER_FILLING_BIT),
};

enum ip_conntrack_expect_events {
	IPEXP_NEW_BIT = 0,
	IPEXP_NEW = (1 << IPEXP_NEW_BIT),
};

#ifdef __KERNEL__
#include <linux/config.h>
#include <linux/netfilter_ipv4/ip_conntrack_tuple.h>
#include <linux/bitops.h>
#include <linux/compiler.h>
#include <asm/atomic.h>

#include <linux/netfilter_ipv4/ip_conntrack_tcp.h>
#include <linux/netfilter_ipv4/ip_conntrack_icmp.h>
#include <linux/netfilter_ipv4/ip_conntrack_proto_gre.h>
#include <linux/netfilter_ipv4/ip_conntrack_sctp.h>

/* per conntrack: protocol private data */
union ip_conntrack_proto {
	/* insert conntrack proto private data here */
	struct ip_ct_gre gre;
	struct ip_ct_sctp sctp;
	struct ip_ct_tcp tcp;
	struct ip_ct_icmp icmp;
};

union ip_conntrack_expect_proto {
	/* insert expect proto private data here */
};

/* Add protocol helper include file here */
#include <linux/netfilter_ipv4/ip_conntrack_pptp.h>
#include <linux/netfilter_ipv4/ip_conntrack_amanda.h>
#include <linux/netfilter_ipv4/ip_conntrack_ftp.h>
#include <linux/netfilter_ipv4/ip_conntrack_irc.h>

/* per conntrack: application helper private data */
union ip_conntrack_help {
	/* insert conntrack helper private data (master) here */
	struct ip_ct_pptp_master ct_pptp_info;
	struct ip_ct_ftp_master ct_ftp_info;
	struct ip_ct_irc_master ct_irc_info;
};

#ifdef CONFIG_IP_NF_NAT_NEEDED
#include <linux/netfilter_ipv4/ip_nat.h>
#include <linux/netfilter_ipv4/ip_nat_pptp.h>

/* per conntrack: nat application helper private data */
union ip_conntrack_nat_help {
	/* insert nat helper private data here */
	struct ip_nat_pptp nat_pptp_info;
};
#endif

#include <linux/types.h>
#include <linux/skbuff.h>

#ifdef CONFIG_NETFILTER_DEBUG
#define IP_NF_ASSERT(x)							\
do {									\
	if (!(x))							\
		/* Wooah!  I'm tripping my conntrack in a frenzy of	\
		   netplay... */					\
		printk("NF_IP_ASSERT: %s:%i(%s)\n",			\
		       __FILE__, __LINE__, __FUNCTION__);		\
} while(0)
#else
#define IP_NF_ASSERT(x)
#endif

struct ip_conntrack_counter
{
	u_int32_t packets;
	u_int32_t bytes;
};

struct ip_conntrack_helper;

struct ip_conntrack
{
	/* Usage count in here is 1 for hash table/destruct timer, 1 per skb,
           plus 1 for any connection(s) we are `master' for */
	struct nf_conntrack ct_general;

	/* Have we seen traffic both ways yet? (bitset) */
	unsigned long status;

	/* Timer function; drops refcnt when it goes off. */
	struct timer_list timeout;

#ifdef CONFIG_IP_NF_CT_ACCT
	/* Accounting Information (same cache line as other written members) */
	struct ip_conntrack_counter counters[IP_CT_DIR_MAX];
#endif
	/* If we were expected by an expectation, this will be it */
	struct ip_conntrack *master;

	/* Current number of expected connections */
	unsigned int expecting;

	/* Unique ID that identifies this conntrack*/
	unsigned int id;

	/* Helper, if any. */
	struct ip_conntrack_helper *helper;

	/* Storage reserved for other modules: */
	union ip_conntrack_proto proto;

	union ip_conntrack_help help;

#ifdef CONFIG_IP_NF_NAT_NEEDED
	struct {
		struct ip_nat_info info;
		union ip_conntrack_nat_help help;
#if defined(CONFIG_IP_NF_TARGET_MASQUERADE) || \
	defined(CONFIG_IP_NF_TARGET_MASQUERADE_MODULE)
		int masq_index;
#endif
	} nat;
#endif /* CONFIG_IP_NF_NAT_NEEDED */

#if defined(CONFIG_IP_NF_CONNTRACK_MARK)
	u_int32_t mark;
#endif

	/* Traversed often, so hopefully in different cacheline to top */
	/* These are my tuples; original and reply */
	struct ip_conntrack_tuple_hash tuplehash[IP_CT_DIR_MAX];
};

struct ip_conntrack_expect
{
	/* Internal linked list (global expectation list) */
	struct list_head list;

	/* We expect this tuple, with the following mask */
	struct ip_conntrack_tuple tuple, mask;
 
	/* Function to call after setup and insertion */
	void (*expectfn)(struct ip_conntrack *new,
			 struct ip_conntrack_expect *this);

	/* The conntrack of the master connection */
	struct ip_conntrack *master;