pt_entry_vpn4
addr->v4 = ((struct pt_entry_vpn4 *)pte)->prefix4;
addr->rd = ((struct pt_entry_vpn4 *)pte)->rd;
addr->labellen = ((struct pt_entry_vpn4 *)pte)->labellen;
((struct pt_entry_vpn4 *)pte)->labelstack,
static struct pt_entry_vpn4 pte_vpn4;
const struct pt_entry_vpn4 *va4, *vb4;
va4 = (const struct pt_entry_vpn4 *)a;
vb4 = (const struct pt_entry_vpn4 *)b;
struct pt_entry_vpn4 *pvpn4 = (struct pt_entry_vpn4 *)pte;