- __skb_push(skb, skb->data - skb->nh.raw);
- top_iph = skb->nh.iph;
- esph = (struct ip_esp_hdr *)(skb->nh.raw + top_iph->ihl*4);
- top_iph->tot_len = htons(skb->len + alen);
- *(u8*)(trailer->tail - 1) = top_iph->protocol;
+ skb_push(skb, -skb_network_offset(skb));
+ esph = ip_esp_hdr(skb);
+ *(skb_tail_pointer(trailer) - 1) = *skb_mac_header(skb);
+ *skb_mac_header(skb) = IPPROTO_ESP;
+
+ spin_lock_bh(&x->lock);