AH_SKB_CB
iph = AH_SKB_CB(skb)->tmp;
kfree(AH_SKB_CB(skb)->tmp);
AH_SKB_CB(skb)->tmp = iph;
work_iph = AH_SKB_CB(skb)->tmp;
kfree(AH_SKB_CB(skb)->tmp);
AH_SKB_CB(skb)->tmp = work_iph;
iph_base = AH_SKB_CB(skb)->tmp;
kfree(AH_SKB_CB(skb)->tmp);
AH_SKB_CB(skb)->tmp = iph_base;
work_iph = AH_SKB_CB(skb)->tmp;
kfree(AH_SKB_CB(skb)->tmp);
AH_SKB_CB(skb)->tmp = work_iph;