# How to rotate vector A around another vector B?

Lets say I know what is directly above a turret. I also know where the turrets gun is currently pointing. I would like to know where will the turret's gun will point if I rotate it.

I suppose I could multiply A (.) B, project A on the plane B is a normal of and then do the rotation in 2d and add back A (.) B but I am sure the math should be simpler than that?

-A+2*(A.B)