geoip.go
func (gi *GeoIP) GetNameV6(ip string) (name string, netmask int) {
	if gi.db == nil {
		return
	}

	gi.mu.Lock()
	defer gi.mu.Unlock()

	cip := C.CString(ip)
	defer C.free(unsafe.Pointer(cip))
	cname := C.GeoIP_name_by_addr_v6(gi.db, cip)

	if cname != nil {
		name = C.GoString(cname)
		defer C.free(unsafe.Pointer(cname))
		netmask = int(C.GeoIP_last_netmask(gi.db))
		return
	}
	return
}
func (gi *GeoIP) GetNameV6(ip string) (name string, netmask int) {
	if gi.db == nil {
		return
	}

	gi.mu.Lock()
	defer gi.mu.Unlock()

	cip := C.CString(ip)
	defer C.free(unsafe.Pointer(cip))
	cname := C.GeoIP_name_by_addr_v6(gi.db, cip)

	if cname != nil {
		name = C.GoString(cname)
		defer C.free(unsafe.Pointer(cname))
		netmask = int(C.GeoIP_last_netmask(gi.db))
		return
	}
	return
}
// Same as GetName() but for IPv6 addresses.