}

func setIPv4MulticastLoopback(fd *netFD, v bool) error {
	return syscall.ENOPROTOOPT
}

func joinIPv4Group(fd *netFD, ifi *Interface, ip IP) error {
	return syscall.ENOPROTOOPT
}

func setIPv6MulticastInterface(fd *netFD, ifi *Interface) error {
	return syscall.ENOPROTOOPT
}

func setIPv6MulticastLoopback(fd *netFD, v bool) error {
	return syscall.ENOPROTOOPT
}

		return err
	}
	err := fd.pfd.SetsockoptIPMreq(syscall.IPPROTO_IP, syscall.IP_ADD_MEMBERSHIP, mreq)
	runtime.KeepAlive(fd)
	return wrapSyscallError("setsockopt", err)
}

func setIPv6MulticastInterface(fd *netFD, ifi *Interface) error {
	var v int
	if ifi != nil {
		v = ifi.Index
	}
	err := fd.pfd.SetsockoptInt(syscall.IPPROTO_IPV6, syscall.IPV6_MULTICAST_IF, v)
	runtime.KeepAlive(fd)

	}
	if err := joinIPv4Group(c.fd, ifi, ip); err != nil {
		return err
	}
	return nil
}

func listenIPv6MulticastUDP(c *UDPConn, ifi *Interface, ip IP) error {
	if ifi != nil {
		if err := setIPv6MulticastInterface(c.fd, ifi); err != nil {
			return err
		}
	}
	if err := setIPv6MulticastLoopback(c.fd, false); err != nil {
		return err
	}
	if err := joinIPv6Group(c.fd, ifi, ip); err != nil {
		return err