include/net/netfilter/nf_conntrack_helper.h

/*
 * connection tracking helpers.
 *
 * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
 *	- generalize L3 protocol dependent part.
 *
 * Derived from include/linux/netfiter_ipv4/ip_conntrack_helper.h
 */

#ifndef _NF_CONNTRACK_HELPER_H
#define _NF_CONNTRACK_HELPER_H
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_extend.h>

struct module;

#define NF_CT_HELPER_NAME_LEN	16

struct nf_conntrack_helper {
	struct hlist_node hnode;	/* Internal use. */

	const char *name;		/* name of the module */
	struct module *me;		/* pointer to self */
	const struct nf_conntrack_expect_policy *expect_policy;

	/* Tuple of things we will help (compared against server response) */
	struct nf_conntrack_tuple tuple;

	/* Function to call when data passes; return verdict, or -1 to
           invalidate. */
	int (*help)(struct sk_buff *skb,
		    unsigned int protoff,
		    struct nf_conn *ct,
		    enum ip_conntrack_info conntrackinfo);

	void (*destroy)(struct nf_conn *ct);

	int (*to_nlattr)(struct sk_buff *skb, const struct nf_conn *ct);
	unsigned int expect_class_max;
};

extern struct nf_conntrack_helper *
__nf_conntrack_helper_find(const char *name, u16 l3num, u8 protonum);

extern struct nf_conntrack_helper *
nf_conntrack_helper_try_module_get(const char *name, u16 l3num, u8 protonum);

extern int nf_conntrack_helper_register(struct nf_conntrack_helper *);
extern void nf_conntrack_helper_unregister(struct nf_conntrack_helper *);

extern struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct, gfp_t gfp);

extern int __nf_ct_try_assign_helper(struct nf_conn *ct, struct nf_conn *tmpl,
				     gfp_t flags);

extern void nf_ct_helper_destroy(struct nf_conn *ct);

static inline struct nf_conn_help *nfct_help(const struct nf_conn *ct)
{
	return nf_ct_ext_find(ct, NF_CT_EXT_HELPER);
}

extern int nf_conntrack_helper_init(void);
extern void nf_conntrack_helper_fini(void);

#endif /*_NF_CONNTRACK_HELPER_H*/