Facebook is not about to take Yahoo’s patent suit lying down and is planning to fight Yahoo(s YHOO), according to my sources close to Facebook. Yahoo, earlier this week, filed a broad-ranging patent infringment lawsuit against the social network that is likely to go public soon. While Facebook’s legal response isn’t fully formulated, the company has enough patents in its portfolio to hit back at Yahoo, sources say. The response is likely to come in relatively short order. A Facebook spokesperson declined to comment.