root/include/net/netfilter/nf_conntrack_l3proto.h

INCLUDED FROM

DEFINITIONS

1. __nf_ct_l3proto_find

/*
 * Copyright (C)2003,2004 USAGI/WIDE Project
 *
 * Header for use in defining a given L3 protocol for connection tracking.
 *
 * Author:
 *      Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
 *
 * Derived from include/netfilter_ipv4/ip_conntrack_protocol.h
 */

#ifndef _NF_CONNTRACK_L3PROTO_H
#define _NF_CONNTRACK_L3PROTO_H
#include <linux/netlink.h>
#include <net/netlink.h>
#include <linux/seq_file.h>
#include <net/netfilter/nf_conntrack.h>

struct nf_conntrack_l3proto {
        /* L3 Protocol Family number. ex) PF_INET */
        u_int16_t l3proto;

        /* Protocol name */
        const char *name;

        /*
         * Try to fill in the third arg: nhoff is offset of l3 proto
         * hdr.  Return true if possible.
         */
        bool (*pkt_to_tuple)(const struct sk_buff *skb, unsigned int nhoff,
                             struct nf_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.
         */
        bool (*invert_tuple)(struct nf_conntrack_tuple *inverse,
                             const struct nf_conntrack_tuple *orig);

        /* Print out the per-protocol part of the tuple. */
        int (*print_tuple)(struct seq_file *s,
                           const struct nf_conntrack_tuple *);

        /*
         * Called before tracking. 
         *      *dataoff: offset of protocol header (TCP, UDP,...) in skb
         *      *protonum: protocol number
         */
        int (*get_l4proto)(const struct sk_buff *skb, unsigned int nhoff,
                           unsigned int *dataoff, u_int8_t *protonum);

        int (*tuple_to_nlattr)(struct sk_buff *skb,
                               const struct nf_conntrack_tuple *t);

        /*
         * Calculate size of tuple nlattr
         */
        int (*nlattr_tuple_size)(void);

        int (*nlattr_to_tuple)(struct nlattr *tb[],
                               struct nf_conntrack_tuple *t);
        const struct nla_policy *nla_policy;

        size_t nla_size;

#ifdef CONFIG_SYSCTL
        const char              *ctl_table_path;
#endif /* CONFIG_SYSCTL */

        /* Init l3proto pernet data */
        int (*init_net)(struct net *net);

        /* Module (if any) which this is connected to. */
        struct module *me;
};

extern struct nf_conntrack_l3proto __rcu *nf_ct_l3protos[AF_MAX];

/* Protocol pernet registration. */
int nf_ct_l3proto_pernet_register(struct net *net,
                                  struct nf_conntrack_l3proto *proto);
void nf_ct_l3proto_pernet_unregister(struct net *net,
                                     struct nf_conntrack_l3proto *proto);

/* Protocol global registration. */
int nf_ct_l3proto_register(struct nf_conntrack_l3proto *proto);
void nf_ct_l3proto_unregister(struct nf_conntrack_l3proto *proto);

struct nf_conntrack_l3proto *nf_ct_l3proto_find_get(u_int16_t l3proto);

/* Existing built-in protocols */
extern struct nf_conntrack_l3proto nf_conntrack_l3proto_generic;

static inline struct nf_conntrack_l3proto *
__nf_ct_l3proto_find(u_int16_t l3proto)
{
        if (unlikely(l3proto >= AF_MAX))
                return &nf_conntrack_l3proto_generic;
        return rcu_dereference(nf_ct_l3protos[l3proto]);
}

#endif /*_NF_CONNTRACK_L3PROTO_H*/