addr = &TCPAddr{IP: ip, Port: port}
	case "udp", "udp4", "udp6":
		addr = &UDPAddr{IP: ip, Port: port}
	default:
		return nil, UnknownNetworkError(net)
	}
	return addr, nil
}

func startPlan9(ctx context.Context, net string, addr Addr) (ctl *os.File, dest, proto, name string, err error) {
	var (
		ip   IP
		port int
	)
	switch a := addr.(type) {
	case *TCPAddr:
		proto = "tcp"
		ip = a.IP