net/core/skbuff.c

4596 	unsigned int doffset = head_skb->data - skb_mac_header(head_skb);
4597 	unsigned int offset = doffset;
4631 	__skb_push(head_skb, doffset);
4743 			if (skb_cow_head(nskb, doffset + headroom)) {
4750 			__skb_push(nskb, doffset);
4757 			nskb = __alloc_skb(hsize + doffset + headroom,
4765 			__skb_put(nskb, doffset);
4781 						 doffset + tnl_hlen);
4783 		if (nskb->len == len + doffset)
4796 					skb_headroom(nskb) + doffset;
4885 				skb_checksum(nskb, doffset,
4886 					     nskb->len - doffset, 0);
4888 				skb_headroom(nskb) + doffset;
4914 			SKB_GSO_CB(iter)->data_offset = skb_headroom(iter) + doffset;
4917 		if (tail->len - doffset <= gso_size)
4920 			skb_shinfo(tail)->gso_segs = DIV_ROUND_UP(tail->len - doffset, gso_size);