nixos-configs/nixosModules/steam.nix

{ lib, config, ... }:
{
  options.my.steam.enable = lib.mkEnableOption "Steam gaming platform";

  config = lib.mkIf config.my.steam.enable {
    hardware.steam-hardware.enable = true;

    programs = {
      steam = {
        enable = true;
        remotePlay.openFirewall = true;
        dedicatedServer.openFirewall = true;
        localNetworkGameTransfers.openFirewall = true;
        gamescopeSession.enable = false;
      };
      gamemode.enable = true;
    };

    # steam network transfer
    networking.firewall = {
      allowedUDPPorts = [ 3478 ];
      allowedTCPPorts = [ 24070 ];

      allowedTCPPortRanges = [
        {
          from = 27015;
          to = 27050;
        }
      ];

      allowedUDPPortRanges = [
        {
          from = 4379;
          to = 4380;
        }
        {
          from = 27000;
          to = 27100;
        }
      ];
    };

    allowedUnfreePackages = [
      "steam"
      "steam-original"
      "steam-run"
      "steam-unwrapped"
    ];
  };
}