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         /* 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         int (*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         int (*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         /* Print out the private part of the conntrack. */
  46         int (*print_conntrack)(struct seq_file *s, const struct nf_conn *);
  47
  48         /* Returns verdict for packet, or -1 for invalid. */
  49         int (*packet)(struct nf_conn *conntrack,
  50                       const struct sk_buff *skb,
  51                       enum ip_conntrack_info ctinfo);
  52
  53         /*
  54          * Called when a new connection for this protocol found;
  55          * returns TRUE if it's OK.  If so, packet() called next.
  56          */
  57         int (*new)(struct nf_conn *conntrack, const struct sk_buff *skb);
  58
  59         /*
  60          * Called before tracking.
  61          *      *dataoff: offset of protocol header (TCP, UDP,...) in skb
  62          *      *protonum: protocol number
  63          */
  64         int (*get_l4proto)(const struct sk_buff *skb, unsigned int nhoff,
  65                            unsigned int *dataoff, u_int8_t *protonum);
  66
  67         int (*tuple_to_nfattr)(struct sk_buff *skb,
  68                                const struct nf_conntrack_tuple *t);
  69
  70         int (*nfattr_to_tuple)(struct nfattr *tb[],
  71                                struct nf_conntrack_tuple *t);
  72
  73 #ifdef CONFIG_SYSCTL
  74         struct ctl_table_header *ctl_table_header;
  75         struct ctl_table        *ctl_table_path;
  76         struct ctl_table        *ctl_table;
  77 #endif /* CONFIG_SYSCTL */
  78
  79         /* Module (if any) which this is connected to. */
  80         struct module *me;
  81 };
  82
  83 extern struct nf_conntrack_l3proto *nf_ct_l3protos[AF_MAX];
  84
  85 /* Protocol registration. */
  86 extern int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto);
  87 extern void nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto);
  88 extern struct nf_conntrack_l3proto *nf_ct_l3proto_find_get(u_int16_t l3proto);
  89 extern void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p);
  90
  91 /* Existing built-in protocols */
  92 extern struct nf_conntrack_l3proto nf_conntrack_l3proto_generic;
  93
  94 static inline struct nf_conntrack_l3proto *
  95 __nf_ct_l3proto_find(u_int16_t l3proto)
  96 {
  97         if (unlikely(l3proto >= AF_MAX))
  98                 return &nf_conntrack_l3proto_generic;
  99         return rcu_dereference(nf_ct_l3protos[l3proto]);
 100 }
 101
 102 #endif /*_NF_CONNTRACK_L3PROTO_H*/