anchor.diff:      }
     else 
       throw "You must either specify contents of the config file or the config file itself for GVPE";
  +
     ifupScript = if cfg.ipAddress == null || cfg.subnet == null then 
        throw "Specify IP address and subnet (with mask) for GVPE" 
      else if cfg.nodename == null then 
  
positive.code:         chown root /var/gvpe
          chmod 700 /var/gvpe
          cp ${finalConfig} /var/gvpe/gvpe.conf
  	cp ${ifupScript} /var/gvpe/if-up
        '';
  
        inherit exec;
  
negative.code:       };
      };
    };
    config = mkIf cfg.enable {
      jobs.gvpe = {
        description = "GNU Virtual Private Ethernet node";
        
  