title: Project Floodlight - Listening for openflow messages
body: <p>I am using project Floodlight to understand the software defined networking for my personal project. My custom module uses floodlightProvider controller module and IOFMessageListener to listen for openflow messages. I can successfully listen to PACKET_IN openflow messages, however I am not able to listen to any synchronous openflow messages(HELLO, EQHO_REQUEST, etc). I followed the documentation and if I am not mistaken, openflow messages can be listened by using the floodlightProvider controller module. Can anyone assist me as I am very curious. The program for listening for messages is given on floodlight tutorial under &quot;how to write a module&quot; . However, I am editing the startup method and the receive method. Those are as follows:</p>
  <pre><code>@Override
  public void startUp(FloodlightModuleContext context) {
      floodlightProvider.addOFMessageListener(OFType.PACKET_IN, this);
      floodlightProvider.addOFMessageListener(OFType.HELLO, this);
  }
  
  @Override
     public net.floodlightcontroller.core.IListener.Command receive(IOFSwitch sw, OFMessage msg, FloodlightContext cntx) {
          switch(msg.getType()){
              case PACKET_IN:
               // print the openflow message in console
                  break;
              case HELLO:
              // print the openflow message in console
                 break;
              default:
                 break;
  }
          return Command.CONTINUE;
      }
  </code></pre>