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/seq_file.h>
  15 #include <net/netfilter/nf_conntrack.h>
  16
  17 struct nf_conntrack_l3proto
  18 {
  19         /* Next pointer. */
  20         struct list_head list;
  21
  22         /* L3 Protocol Family number. ex) PF_INET */
  23         u_int16_t l3proto;
  24
  25         /* Protocol name */
  26         const char *name;
  27
  28         /*
  29          * Try to fill in the third arg: nhoff is offset of l3 proto
  30          * hdr.  Return true if possible.
  31          */
  32         int (*pkt_to_tuple)(const struct sk_buff *skb, unsigned int nhoff,
  33                             struct nf_conntrack_tuple *tuple);
  34
  35         /*
  36          * Invert the per-proto part of the tuple: ie. turn xmit into reply.
  37          * Some packets can't be inverted: return 0 in that case.
  38          */
  39         int (*invert_tuple)(struct nf_conntrack_tuple *inverse,
  40                             const struct nf_conntrack_tuple *orig);
  41
  42         /* Print out the per-protocol part of the tuple. */
  43         int (*print_tuple)(struct seq_file *s,
  44                            const struct nf_conntrack_tuple *);
  45
  46         /* Print out the private part of the conntrack. */
  47         int (*print_conntrack)(struct seq_file *s, const struct nf_conn *);
  48
  49         /* Returns verdict for packet, or -1 for invalid. */
  50         int (*packet)(struct nf_conn *conntrack,
  51                       const struct sk_buff *skb,
  52                       enum ip_conntrack_info ctinfo);
  53
  54         /*
  55          * Called when a new connection for this protocol found;
  56          * returns TRUE if it's OK.  If so, packet() called next.
  57          */
  58         int (*new)(struct nf_conn *conntrack, const struct sk_buff *skb);
  59
  60         /* Called when a conntrack entry is destroyed */
  61         void (*destroy)(struct nf_conn *conntrack);
  62
  63         /*
  64          * Called before tracking.
  65          *      *dataoff: offset of protocol header (TCP, UDP,...) in *pskb
  66          *      *protonum: protocol number
  67          */
  68         int (*prepare)(struct sk_buff **pskb, unsigned int hooknum,
  69                        unsigned int *dataoff, u_int8_t *protonum);
  70
  71         u_int32_t (*get_features)(const struct nf_conntrack_tuple *tuple);
  72
  73         /* Module (if any) which this is connected to. */
  74         struct module *me;
  75 };
  76
  77 extern struct nf_conntrack_l3proto *nf_ct_l3protos[AF_MAX];
  78
  79 /* Protocol registration. */
  80 extern int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto);
  81 extern void nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto);
  82
  83 static inline struct nf_conntrack_l3proto *
  84 nf_ct_find_l3proto(u_int16_t l3proto)
  85 {
  86         return nf_ct_l3protos[l3proto];
  87 }
  88
  89 /* Existing built-in protocols */
  90 extern struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4;
  91 extern struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv6;
  92 extern struct nf_conntrack_l3proto nf_conntrack_generic_l3proto;
  93 #endif /*_NF_CONNTRACK_L3PROTO_H*/