NixOS-Config/modules/nixos/vpn-ip/default.nix

{lib, ...}:
with lib; {
  # Declare what settings a user of this "hello.nix" module CAN SET.
  options.services.vpn-ip = {
    enable = mkOption {
      type = types.bool;
      default = true;
    };
    ip = mkOption {
      type = types.str;
      default = "0";
    };
    publicKey = mkOption {
      type = types.str;
      default = "";
    };
  };
}