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 nfattr;
  18
  19 struct nf_conntrack_l3proto
  20 {
  21         /* Next pointer. */
  22         struct list_head list;
  23
  24         /* L3 Protocol Family number. ex) PF_INET */
  25         u_int16_t l3proto;
  26
  27         /* Protocol name */
  28         const char *name;
  29
  30         /*
  31          * Try to fill in the third arg: nhoff is offset of l3 proto
  32          * hdr.  Return true if possible.
  33          */
  34         int (*pkt_to_tuple)(const struct sk_buff *skb, unsigned int nhoff,
  35                             struct nf_conntrack_tuple *tuple);
  36
  37         /*
  38          * Invert the per-proto part of the tuple: ie. turn xmit into reply.
  39          * Some packets can't be inverted: return 0 in that case.
  40          */
  41         int (*invert_tuple)(struct nf_conntrack_tuple *inverse,
  42                             const struct nf_conntrack_tuple *orig);
  43
  44         /* Print out the per-protocol part of the tuple. */
  45         int (*print_tuple)(struct seq_file *s,
  46                            const struct nf_conntrack_tuple *);
  47
  48         /* Print out the private part of the conntrack. */
  49         int (*print_conntrack)(struct seq_file *s, const struct nf_conn *);
  50
  51         /* Returns verdict for packet, or -1 for invalid. */
  52         int (*packet)(struct nf_conn *conntrack,
  53                       const struct sk_buff *skb,
  54                       enum ip_conntrack_info ctinfo);
  55
  56         /*
  57          * Called when a new connection for this protocol found;
  58          * returns TRUE if it's OK.  If so, packet() called next.
  59          */
  60         int (*new)(struct nf_conn *conntrack, const struct sk_buff *skb);
  61
  62         /* Called when a conntrack entry is destroyed */
  63         void (*destroy)(struct nf_conn *conntrack);
  64
  65         /*
  66          * Called before tracking.
  67          *      *dataoff: offset of protocol header (TCP, UDP,...) in *pskb
  68          *      *protonum: protocol number
  69          */
  70         int (*prepare)(struct sk_buff **pskb, unsigned int hooknum,
  71                        unsigned int *dataoff, u_int8_t *protonum);
  72
  73         u_int32_t (*get_features)(const struct nf_conntrack_tuple *tuple);
  74
  75         int (*tuple_to_nfattr)(struct sk_buff *skb,
  76                                const struct nf_conntrack_tuple *t);
  77
  78         int (*nfattr_to_tuple)(struct nfattr *tb[],
  79                                struct nf_conntrack_tuple *t);
  80
  81         /* Module (if any) which this is connected to. */
  82         struct module *me;
  83 };
  84
  85 extern struct nf_conntrack_l3proto *nf_ct_l3protos[AF_MAX];
  86
  87 /* Protocol registration. */
  88 extern int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto);
  89 extern void nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto);
  90
  91 extern struct nf_conntrack_l3proto *
  92 nf_ct_l3proto_find_get(u_int16_t l3proto);
  93
  94 extern void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p);
  95
  96 /* Existing built-in protocols */
  97 extern struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4;
  98 extern struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv6;
  99 extern struct nf_conntrack_l3proto nf_conntrack_generic_l3proto;
 100
 101 static inline struct nf_conntrack_l3proto *
 102 __nf_ct_l3proto_find(u_int16_t l3proto)
 103 {
 104         if (unlikely(l3proto >= AF_MAX))
 105                 return &nf_conntrack_generic_l3proto;
 106         return nf_ct_l3protos[l3proto];
 107 }
 108
 109 #endif /*_NF_CONNTRACK_L3PROTO_H*/