include/net/netfilter/nf_conntrack_l3proto.h

   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
  19 struct 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         void (*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         /* Init l3proto pernet data */
  67         int (*init_net)(struct net *net);
  68
  69         /* Module (if any) which this is connected to. */
  70         struct module *me;
  71 };
  72
  73 extern struct nf_conntrack_l3proto __rcu *nf_ct_l3protos[AF_MAX];
  74
  75 /* Protocol pernet registration. */
  76 int nf_ct_l3proto_pernet_register(struct net *net,
  77                                   struct nf_conntrack_l3proto *proto);
  78 void nf_ct_l3proto_pernet_unregister(struct net *net,
  79                                      struct nf_conntrack_l3proto *proto);
  80
  81 /* Protocol global registration. */
  82 int nf_ct_l3proto_register(struct nf_conntrack_l3proto *proto);
  83 void nf_ct_l3proto_unregister(struct nf_conntrack_l3proto *proto);
  84
  85 struct nf_conntrack_l3proto *nf_ct_l3proto_find_get(u_int16_t l3proto);
  86
  87 /* Existing built-in protocols */
  88 extern struct nf_conntrack_l3proto nf_conntrack_l3proto_generic;
  89
  90 static inline struct nf_conntrack_l3proto *
  91 __nf_ct_l3proto_find(u_int16_t l3proto)
  92 {
  93         if (unlikely(l3proto >= AF_MAX))
  94                 return &nf_conntrack_l3proto_generic;
  95         return rcu_dereference(nf_ct_l3protos[l3proto]);
  96 }
  97
  98 #endif /*_NF_CONNTRACK_L3PROTO_H*/