LXR linux/include/net/netfilter/nf_conntrack

   1/*
   2 * Copyright (C)2003,2004 USAGI/WIDE Project
   3 *
   4 * Header for use in defining a given L3 protocol for connection tracking.
   5 *
   6 * Author:
   7 *      Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
   8 *
   9 * Derived from include/netfilter_ipv4/ip_conntrack_protocol.h
  10 */
  11
  12#ifndef _NF_CONNTRACK_L3PROTO_H
  13#define _NF_CONNTRACK_L3PROTO_H
  14#include <linux/netlink.h>
  15#include <net/netlink.h>
  16#include <linux/seq_file.h>
  17#include <net/netfilter/nf_conntrack.h>
  18
  19struct nf_conntrack_l3proto {
  20        /* L3 Protocol Family number. ex) PF_INET */
  21        u_int16_t l3proto;
  22
  23        /* Protocol name */
  24        const char *name;
  25
  26        /*
  27         * Try to fill in the third arg: nhoff is offset of l3 proto
  28         * hdr.  Return true if possible.
  29         */
  30        bool (*pkt_to_tuple)(const struct sk_buff *skb, unsigned int nhoff,
  31                             struct nf_conntrack_tuple *tuple);
  32
  33        /*
  34         * Invert the per-proto part of the tuple: ie. turn xmit into reply.
  35         * Some packets can't be inverted: return 0 in that case.
  36         */
  37        bool (*invert_tuple)(struct nf_conntrack_tuple *inverse,
  38                             const struct nf_conntrack_tuple *orig);
  39
  40        /* Print out the per-protocol part of the tuple. */
  41        int (*print_tuple)(struct seq_file *s,
  42                           const struct nf_conntrack_tuple *);
  43
  44        /*
  45         * Called before tracking. 
  46         *      *dataoff: offset of protocol header (TCP, UDP,...) in skb
  47         *      *protonum: protocol number
  48         */
  49        int (*get_l4proto)(const struct sk_buff *skb, unsigned int nhoff,
  50                           unsigned int *dataoff, u_int8_t *protonum);
  51
  52        int (*tuple_to_nlattr)(struct sk_buff *skb,
  53                               const struct nf_conntrack_tuple *t);
  54
  55        /*
  56         * Calculate size of tuple nlattr
  57         */
  58        int (*nlattr_tuple_size)(void);
  59
  60        int (*nlattr_to_tuple)(struct nlattr *tb[],
  61                               struct nf_conntrack_tuple *t);
  62        const struct nla_policy *nla_policy;
  63
  64        size_t nla_size;
  65
  66#ifdef CONFIG_SYSCTL
  67        struct ctl_table_header *ctl_table_header;
  68        struct ctl_path         *ctl_table_path;
  69        struct ctl_table        *ctl_table;
  70#endif /* CONFIG_SYSCTL */
  71
  72        /* Module (if any) which this is connected to. */
  73        struct module *me;
  74};
  75
  76extern struct nf_conntrack_l3proto __rcu *nf_ct_l3protos[AF_MAX];
  77
  78/* Protocol registration. */
  79extern int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto);
  80extern void nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto);
  81extern struct nf_conntrack_l3proto *nf_ct_l3proto_find_get(u_int16_t l3proto);
  82extern void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p);
  83
  84/* Existing built-in protocols */
  85extern struct nf_conntrack_l3proto nf_conntrack_l3proto_generic;
  86
  87static inline struct nf_conntrack_l3proto *
  88__nf_ct_l3proto_find(u_int16_t l3proto)
  89{
  90        if (unlikely(l3proto >= AF_MAX))
  91                return &nf_conntrack_l3proto_generic;
  92        return rcu_dereference(nf_ct_l3protos[l3proto]);
  93}
  94
  95#endif /*_NF_CONNTRACK_L3PROTO_H*/
  96