How do I get the closest Spline Control Point

[Lupos]

I've tried figuring out how to get the closet control point but nothing I've found gets me what I need. The closest I could find was TFToSegment, but that gives me a segment, not the control points. 

I'm trying to get the closest control point to my mouse position, so if I had a spline of 2 control points, and I'm at the start of a spline, I'd be at control point 1, if I was at the end of the spline, I'd be at control point 2