#ifndef _IP_NAT_HELPER_H#define _IP_NAT_HELPER_H/* NAT protocol helper routines. */#include <linux/netfilter_ipv4/ip_conntrack.h>struct sk_buff;/* Flags *//* NAT helper must be called on every packet (for TCP) */#define IP_NAT_HELPER_F_ALWAYS		0x01/* Standalone NAT helper, without a conntrack part */#define IP_NAT_HELPER_F_STANDALONE	0x02struct ip_nat_helper{	struct list_head list;		/* Internal use */	const char *name;		/* name of the module */	unsigned char flags;		/* Flags (see above) */	struct module *me;		/* pointer to self */		/* Mask of things we will help: vs. tuple from server */	struct ip_conntrack_tuple tuple;	struct ip_conntrack_tuple mask;		/* Helper function: returns verdict */	unsigned int (*help)(struct ip_conntrack *ct,			     struct ip_conntrack_expect *exp,			     struct ip_nat_info *info,			     enum ip_conntrack_info ctinfo,			     unsigned int hooknum,			     struct sk_buff **pskb);	/* Returns verdict and sets up NAT for this connection */	unsigned int (*expect)(struct sk_buff **pskb,			       unsigned int hooknum,			       struct ip_conntrack *ct,			       struct ip_nat_info *info);};extern struct list_head helpers;extern int ip_nat_helper_register(struct ip_nat_helper *me);extern void ip_nat_helper_unregister(struct ip_nat_helper *me);extern int ip_nat_mangle_tcp_packet(struct sk_buff **skb,				struct ip_conntrack *ct,				enum ip_conntrack_info ctinfo,				unsigned int match_offset,				unsigned int match_len,				char *rep_buffer,				unsigned int rep_len);extern int ip_nat_mangle_udp_packet(struct sk_buff **skb,				struct ip_conntrack *ct,				enum ip_conntrack_info ctinfo,				unsigned int match_offset,				unsigned int match_len,				char *rep_buffer,				unsigned int rep_len);extern int ip_nat_seq_adjust(struct sk_buff *skb,				struct ip_conntrack *ct,				enum ip_conntrack_info ctinfo);extern void ip_nat_delete_sack(struct sk_buff *skb);#endif