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         int (*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 #ifdef CONFIG_SYSCTL
  67         const char              *ctl_table_path;
  68 #endif /* CONFIG_SYSCTL */
  69
  70         /* Init l3proto pernet data */
  71         int (*init_net)(struct net *net);
  72
  73         /* Module (if any) which this is connected to. */
  74         struct module *me;
  75 };
  76
  77 extern struct nf_conntrack_l3proto __rcu *nf_ct_l3protos[AF_MAX];
  78
  79 /* Protocol pernet registration. */
  80 extern int nf_ct_l3proto_pernet_register(struct net *net,
  81                                          struct nf_conntrack_l3proto *proto);
  82 extern void nf_ct_l3proto_pernet_unregister(struct net *net,
  83                                             struct nf_conntrack_l3proto *proto);
  84
  85 /* Protocol global registration. */
  86 extern int nf_ct_l3proto_register(struct nf_conntrack_l3proto *proto);
  87 extern void nf_ct_l3proto_unregister(struct nf_conntrack_l3proto *proto);
  88
  89 extern struct nf_conntrack_l3proto *nf_ct_l3proto_find_get(u_int16_t l3proto);
  90 extern void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p);
  91
  92 /* Existing built-in protocols */
  93 extern struct nf_conntrack_l3proto nf_conntrack_l3proto_generic;
  94
  95 static inline struct nf_conntrack_l3proto *
  96 __nf_ct_l3proto_find(u_int16_t l3proto)
  97 {
  98         if (unlikely(l3proto >= AF_MAX))
  99                 return &nf_conntrack_l3proto_generic;
 100         return rcu_dereference(nf_ct_l3protos[l3proto]);
 101 }
 102
 103 #endif /*_NF_CONNTRACK_L3PROTO_H*/