# File common/lib/symbiosis/host.rb, line 226
    def self.primary_interface
      route = self.netlink_socket.route.read_route.select do |rt|
        rt.scope == 0 and rt.type == 1 and !rt.gateway.nil?
      end.sort{|a,b| a.oif <=> b.oif}.first

      return nil if route.nil?

      #
      # Bit of an omission.  Need for the #find method.
      #
      self.netlink_socket.link.extend(Enumerable)

      primary_interface = self.netlink_socket.link.find{|l| route.oif == l.index }

      return primary_interface
    end