extern int ip_fragment(struct sk_buff *skb, int (*out)(struct sk_buff*));
extern int ip_do_nat(struct sk_buff *skb);
extern void ip_send_check(struct iphdr *ip);
extern int ip_fragment(struct sk_buff *skb, int (*out)(struct sk_buff*));
extern int ip_do_nat(struct sk_buff *skb);
extern void ip_send_check(struct iphdr *ip);