root/include/net/netfilter/nf_nat_l4proto.h

/* Header for use in defining a given protocol. */
#ifndef _NF_NAT_L4PROTO_H
#define _NF_NAT_L4PROTO_H
#include <net/netfilter/nf_nat.h>
#include <linux/netfilter/nfnetlink_conntrack.h>

struct nf_nat_range;
struct nf_nat_l3proto;

struct nf_nat_l4proto {
        /* Protocol number. */
        u8 l4proto;

        /* Translate a packet to the target according to manip type.
         * Return true if succeeded.
         */
        bool (*manip_pkt)(struct sk_buff *skb,
                          const struct nf_nat_l3proto *l3proto,
                          unsigned int iphdroff, unsigned int hdroff,
                          const struct nf_conntrack_tuple *tuple,
                          enum nf_nat_manip_type maniptype);

        /* Is the manipable part of the tuple between min and max incl? */
        bool (*in_range)(const struct nf_conntrack_tuple *tuple,
                         enum nf_nat_manip_type maniptype,
                         const union nf_conntrack_man_proto *min,
                         const union nf_conntrack_man_proto *max);

        /* Alter the per-proto part of the tuple (depending on
         * maniptype), to give a unique tuple in the given range if
         * possible.  Per-protocol part of tuple is initialized to the
         * incoming packet.
         */
        void (*unique_tuple)(const struct nf_nat_l3proto *l3proto,
                             struct nf_conntrack_tuple *tuple,
                             const struct nf_nat_range *range,
                             enum nf_nat_manip_type maniptype,
                             const struct nf_conn *ct);

        int (*nlattr_to_range)(struct nlattr *tb[],
                               struct nf_nat_range *range);
};

/* Protocol registration. */
int nf_nat_l4proto_register(u8 l3proto, const struct nf_nat_l4proto *l4proto);
void nf_nat_l4proto_unregister(u8 l3proto,
                               const struct nf_nat_l4proto *l4proto);

const struct nf_nat_l4proto *__nf_nat_l4proto_find(u8 l3proto, u8 l4proto);

/* Built-in protocols. */
extern const struct nf_nat_l4proto nf_nat_l4proto_tcp;
extern const struct nf_nat_l4proto nf_nat_l4proto_udp;
extern const struct nf_nat_l4proto nf_nat_l4proto_icmp;
extern const struct nf_nat_l4proto nf_nat_l4proto_icmpv6;
extern const struct nf_nat_l4proto nf_nat_l4proto_unknown;

bool nf_nat_l4proto_in_range(const struct nf_conntrack_tuple *tuple,
                             enum nf_nat_manip_type maniptype,
                             const union nf_conntrack_man_proto *min,
                             const union nf_conntrack_man_proto *max);

void nf_nat_l4proto_unique_tuple(const struct nf_nat_l3proto *l3proto,
                                 struct nf_conntrack_tuple *tuple,
                                 const struct nf_nat_range *range,
                                 enum nf_nat_manip_type maniptype,
                                 const struct nf_conn *ct, u16 *rover);

int nf_nat_l4proto_nlattr_to_range(struct nlattr *tb[],
                                   struct nf_nat_range *range);

#endif /*_NF_NAT_L4PROTO_H*/