Where to initialize clients in C server?

I’m writing a multiplayer server in C using sockets and pthreads. The project is separated by responsibility:

-- server.c/.h → networking (socket, bind, listen, accept, thread creation)

-- player.c/.h → player data structure and functions

-- game.c/.h → game logic

-- config.h → constants

When a new client connects, I need to:

1. Ask the client for a username

2. Validate it (check uniqueness)

3. Create a player object

4. Add it to the global player list

5. Then move the client into the lobby/menu loop

Right now this logic is inside a function like handle_client(...), which is called after accept().

Where should this function belong?

1. Inside server.c, meaning the server handles both networking and player initialization?

2. Inside player.c, even though that mixes networking I/O with data structure logic?

3. Or should I create a new module, e.g., controller.c, where the server only accepts sockets and the controller handles client interaction flow?

I want to maintain clean separation of responsibilities. Which design makes more sense?