gtp1_header
mtu -= sizeof(struct gtp1_header);
mtu -= sizeof(struct gtp1_header);
len_hdr = sizeof(struct gtp1_header);
sizeof(struct gtp1_header);
struct gtp1_header *gtp1;
gtp1 = (struct gtp1_header *)(skb->data + sizeof(struct udphdr));
gtp1 = (struct gtp1_header *)(skb->data + sizeof(struct udphdr));
struct gtp1_header *gtp1;