Hello everyone,
I am in the process of remodeling my bathroom. The existing shower had 2" concrete walls and a concrete floor with tile. The drain is just a 4" pipe. There is a trap below.

What do I need to do to connect a standard shower drain to this. I would like to prevent breaking up the floor if at all possible. My initial idea is to insert a rubber donut into the pipe, and insert a clamping drain into the other end of the rubber piece. Then, put a liner down and mortar over that. Finally, insert the top piece of the drain and tile. The floor now is sloped.

I obviously don't know anything about plumbing. Will this work? Is there a better method? Do I need to tear up the floor?