{ pkgs, ... }:

with pkgs.lib;
let
  generate-mac-address = hostname: interface: pkgs.stdenv.mkDerivation {
    name = "mk-mac-${hostname}-${interface}";
    phases = [ "installPhase" ];
    installPhase = ''
      echo ${hostname}-${interface} | sha1sum | sed 's/^\(..\)\(..\)\(..\)\(..\)\(..\).*$/02:\1:\2:\3:\4:\5/' > $out
    '';
  };

in {
  generate-mac-address = hostname: interface: let
    pkg = generate-mac-address hostname interface;
  in builtins.readFile "${pkg}";
}