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