#ifndef _NET_AH_H
  #define _NET_AH_H

  #include <linux/skbuff.h>

  
  /* This is the maximum truncated ICV length that we know of. */

  #define MAX_AH_AUTH_LEN	64

  struct crypto_ahash;

  struct ah_data {

  	int			icv_full_len;
  	int			icv_trunc_len;

  	struct crypto_ahash	*ahash;

  };

  struct ip_auth_hdr;
  
  static inline struct ip_auth_hdr *ip_auth_hdr(const struct sk_buff *skb)
  {
  	return (struct ip_auth_hdr *)skb_transport_header(skb);
  }

  #endif