#ifndef _NET_ESP_H
  #define _NET_ESP_H

  #include <linux/skbuff.h>

  struct crypto_aead;

  struct esp_data {
  	/* 0..255 */
  	int padlen;
  
  	/* Confidentiality & Integrity */
  	struct crypto_aead *aead;

  };

  extern void *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len);

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

  #endif