extern int ip_xfrm_me_harder(struct sk_buff **pskb);
extern unsigned int nf_ip_checksum(struct sk_buff *skb, unsigned int hook,
unsigned int dataoff, u_int8_t protocol);
extern int ip_xfrm_me_harder(struct sk_buff **pskb);
extern unsigned int nf_ip_checksum(struct sk_buff *skb, unsigned int hook,
unsigned int dataoff, u_int8_t protocol);