コントローラの継承.rb

# L2 routing path manager
class PathManager < Trema::Controller
  def packet_in(_dpid, message)
    path = maybe_create_shortest_path(message)
    ports = path ? [path.out_port] : @graph.external_ports
    ports.each do |each|
      send_packet_out(each.dpid,
                      raw_data: message.raw_data,
                      actions: SendOutPort.new(each.number))
    end
  end
  # ...
end

# L2 routing switch with virtual slicing.
class SliceableSwitch < PathManager
  def packet_in(_dpid, packet_in)
    slice = find_slice(packet_in.slice_source,
                       packet_in.slice_destination(@graph))
    if slice
      path = maybe_create_shortest_path_in_slice(slice.name, packet_in)
      packet_out_to_destination(packet_in, path.out_port) if path
    else
      flood_to_external_ports(packet_in)
    end
  end