var p unsafe.Pointer
	if len(filter) > 0 {
		p = unsafe.Pointer(&filter[0])
	}
	return setsockopt(fd, level, opt, p, uintptr(len(filter)*SizeofCanFilter))
}

func SetsockoptTpacketReq(fd, level, opt int, tp *TpacketReq) error {
	return setsockopt(fd, level, opt, unsafe.Pointer(tp), unsafe.Sizeof(*tp))
}

func SetsockoptTpacketReq3(fd, level, opt int, tp *TpacketReq3) error {