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{
  21        /* L3 Protocol Family number. ex) PF_INET */
  22        u_int16_t l3proto;
  23
  24        /* Protocol name */
  25        const char *name;
  26
  27        /*
  28         * Try to fill in the third arg: nhoff is offset of l3 proto
  29         * hdr.  Return true if possible.
  30         */
  31        bool (*pkt_to_tuple)(const struct sk_buff *skb, unsigned int nhoff,
  32                             struct nf_conntrack_tuple *tuple);
  33
  34        /*
  35         * Invert the per-proto part of the tuple: ie. turn xmit into reply.
  36         * Some packets can't be inverted: return 0 in that case.
  37         */
  38        bool (*invert_tuple)(struct nf_conntrack_tuple *inverse,
  39                             const struct nf_conntrack_tuple *orig);
  40
  41        /* Print out the per-protocol part of the tuple. */
  42        int (*print_tuple)(struct seq_file *s,
  43                           const struct nf_conntrack_tuple *);
  44
  45        /*
  46         * Called before tracking. 
  47         *      *dataoff: offset of protocol header (TCP, UDP,...) in skb
  48         *      *protonum: protocol number
  49         */
  50        int (*get_l4proto)(const struct sk_buff *skb, unsigned int nhoff,
  51                           unsigned int *dataoff, u_int8_t *protonum);
  52
  53        int (*tuple_to_nlattr)(struct sk_buff *skb,
  54                               const struct nf_conntrack_tuple *t);
  55
  56        /*
  57         * Calculate size of tuple nlattr
  58         */
  59        int (*nlattr_tuple_size)(void);
  60
  61        int (*nlattr_to_tuple)(struct nlattr *tb[],
  62                               struct nf_conntrack_tuple *t);
  63        const struct nla_policy *nla_policy;
  64
  65        size_t nla_size;
  66
  67#ifdef CONFIG_SYSCTL
  68        struct ctl_table_header *ctl_table_header;
  69        struct ctl_path         *ctl_table_path;
  70        struct ctl_table        *ctl_table;
  71#endif /* CONFIG_SYSCTL */
  72
  73        /* Module (if any) which this is connected to. */
  74        struct module *me;
  75};
  76
  77extern struct nf_conntrack_l3proto *nf_ct_l3protos[AF_MAX];
  78
  79/* Protocol registration. */
  80extern int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto);
  81extern void nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto);
  82extern struct nf_conntrack_l3proto *nf_ct_l3proto_find_get(u_int16_t l3proto);
  83extern void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p);
  84
  85/* Existing built-in protocols */
  86extern struct nf_conntrack_l3proto nf_conntrack_l3proto_generic;
  87
  88static inline struct nf_conntrack_l3proto *
  89__nf_ct_l3proto_find(u_int16_t l3proto)
  90{
  91        if (unlikely(l3proto >= AF_MAX))
  92                return &nf_conntrack_l3proto_generic;
  93        return rcu_dereference(nf_ct_l3protos[l3proto]);
  94}
  95
  96#endif /*_NF_CONNTRACK_L3PROTO_H*/
  97