#ifndef __NET_IPIP_H
  #define __NET_IPIP_H 1
  
  #include <linux/if_tunnel.h>

  #include <net/ip.h>

  
  /* Keep error state on tunnel for 30 sec */
  #define IPTUNNEL_ERR_TIMEO	(30*HZ)

  /* 6rd prefix/relay information */

  struct ip_tunnel_6rd_parm {

  	struct in6_addr		prefix;
  	__be32			relay_prefix;
  	u16			prefixlen;
  	u16			relay_prefixlen;
  };

  struct ip_tunnel {

  	struct ip_tunnel __rcu	*next;

  	struct net_device	*dev;

  	int			err_count;	/* Number of arrived ICMP errors */
  	unsigned long		err_time;	/* Time when the last ICMP error arrived */
  
  	/* These four fields used only by GRE */
  	__u32			i_seqno;	/* The last seen seqno	*/
  	__u32			o_seqno;	/* The last output seqno */
  	int			hlen;		/* Precalculated GRE header length */
  	int			mlink;
  
  	struct ip_tunnel_parm	parms;

  	/* for SIT */
  #ifdef CONFIG_IPV6_SIT_6RD
  	struct ip_tunnel_6rd_parm	ip6rd;
  #endif

  	struct ip_tunnel_prl_entry __rcu *prl;		/* potential router list */

  	unsigned int			prl_count;	/* # of entries in PRL */

  };

  struct ip_tunnel_prl_entry {

  	struct ip_tunnel_prl_entry __rcu *next;

  	__be32				addr;
  	u16				flags;

  	struct rcu_head			rcu_head;

  };

  #define __IPTUNNEL_XMIT(stats1, stats2) do {				\

  	int err;							\

  	int pkt_len = skb->len - skb_transport_offset(skb);		\

  									\
  	skb->ip_summed = CHECKSUM_NONE;					\

  	ip_select_ident(iph, &rt->dst, NULL);				\

  									\

  	err = ip_local_out(skb);					\

  	if (likely(net_xmit_eval(err) == 0)) {				\

  		(stats1)->tx_bytes += pkt_len;				\
  		(stats1)->tx_packets++;					\

  	} else {							\

  		(stats2)->tx_errors++;					\
  		(stats2)->tx_aborted_errors++;				\

  	}								\
  } while (0)

  #define IPTUNNEL_XMIT() __IPTUNNEL_XMIT(txq, stats)

  #endif