/* Header for use in defining a given protocol for connection tracking. */#ifndef _IP_CONNTRACK_PROTOCOL_H#define _IP_CONNTRACK_PROTOCOL_H#include <linux/netfilter_ipv4/ip_conntrack.h>struct ip_conntrack_protocol{	/* Next pointer. */	struct list_head list;	/* Protocol number. */	u_int8_t proto;	/* Protocol name */	const char *name;	/* Try to fill in the third arg; return true if possible. */	int (*pkt_to_tuple)(const void *datah, size_t datalen,			    struct ip_conntrack_tuple *tuple);	/* Invert the per-proto part of the tuple: ie. turn xmit into reply.	 * Some packets can't be inverted: return 0 in that case.	 */	int (*invert_tuple)(struct ip_conntrack_tuple *inverse,			    const struct ip_conntrack_tuple *orig);	/* Print out the per-protocol part of the tuple. */	unsigned int (*print_tuple)(char *buffer,				    const struct ip_conntrack_tuple *);	/* Print out the private part of the conntrack. */	unsigned int (*print_conntrack)(char *buffer,					const struct ip_conntrack *);	/* Returns verdict for packet, or -1 for invalid. */	int (*packet)(struct ip_conntrack *conntrack,		      struct iphdr *iph, size_t len,		      enum ip_conntrack_info ctinfo);	/* Called when a new connection for this protocol found;	 * returns TRUE if it's OK.  If so, packet() called next. */	int (*new)(struct ip_conntrack *conntrack, struct iphdr *iph,		   size_t len);	/* Called when a conntrack entry is destroyed */	void (*destroy)(struct ip_conntrack *conntrack);	/* Has to decide if a expectation matches one packet or not */	int (*exp_matches_pkt)(struct ip_conntrack_expect *exp,			       struct sk_buff **pskb);	/* Module (if any) which this is connected to. */	struct module *me;};/* Protocol registration. */extern int ip_conntrack_protocol_register(struct ip_conntrack_protocol *proto);extern void ip_conntrack_protocol_unregister(struct ip_conntrack_protocol *proto);/* Existing built-in protocols */extern struct ip_conntrack_protocol ip_conntrack_protocol_tcp;extern struct ip_conntrack_protocol ip_conntrack_protocol_udp;extern struct ip_conntrack_protocol ip_conntrack_protocol_icmp;extern int ip_conntrack_protocol_tcp_init(void);#endif /*_IP_CONNTRACK_PROTOCOL_H*/