#ifndef _IF_TUNNEL_H_
  #define _IF_TUNNEL_H_

  #include <linux/types.h>

  #define SIOCGETTUNNEL   (SIOCDEVPRIVATE + 0)
  #define SIOCADDTUNNEL   (SIOCDEVPRIVATE + 1)
  #define SIOCDELTUNNEL   (SIOCDEVPRIVATE + 2)
  #define SIOCCHGTUNNEL   (SIOCDEVPRIVATE + 3)
  
  #define GRE_CSUM	__constant_htons(0x8000)
  #define GRE_ROUTING	__constant_htons(0x4000)
  #define GRE_KEY		__constant_htons(0x2000)
  #define GRE_SEQ		__constant_htons(0x1000)
  #define GRE_STRICT	__constant_htons(0x0800)
  #define GRE_REC		__constant_htons(0x0700)
  #define GRE_FLAGS	__constant_htons(0x00F8)
  #define GRE_VERSION	__constant_htons(0x0007)
  
  struct ip_tunnel_parm
  {
  	char			name[IFNAMSIZ];
  	int			link;

  	__be16			i_flags;
  	__be16			o_flags;
  	__be32			i_key;
  	__be32			o_key;

  	struct iphdr		iph;
  };
  
  #endif /* _IF_TUNNEL_H_ */