manuals/developer-guide/src/main/asciidoc/openflowplugin/odl-ofp-wiring-up-notifications.adoc

   1 === Wiring up notifications
   2
   3 ==== Introduction
   4
   5 We need to translate OpenFlow messages coming up from the
   6 <<_openflow_protocol_library_developer_guide,OpenFlow Protocol Library>>
   7 into MD-SAL Notification objects and then publish them to the
   8 MD-SAL.
   9
  10 [[mechanics]]
  11 ==== Mechanics
  12
  13 .  Create a Translator class
  14 .  Register the Translator
  15 .  Register the notificationPopListener to handle your Notification
  16 Objects
  17
  18 [[create-a-translator-class]]
  19 ===== Create a Translator class
  20
  21 You can see an example in
  22 https://git.opendaylight.org/gerrit/gitweb?p=openflowplugin.git;a=blob;f=openflowplugin/src/main/java/org/opendaylight/openflowplugin/openflow/md/core/translator/PacketInTranslator.java;hb=refs/heads/stable/boron[PacketInTranslator.java].
  23
  24 First, simply create the class
  25
  26 ---------------------------------------------------------------------------------------------
  27 public class PacketInTranslator implements IMDMessageTranslator<OfHeader, List<DataObject>> {
  28 ---------------------------------------------------------------------------------------------
  29
  30 Then implement the translate function:
  31
  32 ---------------------------------------------------------------------------------------------
  33 public class PacketInTranslator implements IMDMessageTranslator<OfHeader, List<DataObject>> {
  34
  35     protected static final Logger LOG = LoggerFactory
  36             .getLogger(PacketInTranslator.class);
  37     @Override
  38     public PacketReceived translate(SwitchConnectionDistinguisher cookie,
  39             SessionContext sc, OfHeader msg) {
  40             ...
  41     }
  42 ---------------------------------------------------------------------------------------------
  43
  44 Make sure to check that you are dealing with the expected type and cast
  45 it:
  46
  47 ---------------------------------------------------------------------------
  48 if(msg instanceof PacketInMessage) {
  49     PacketInMessage message = (PacketInMessage)msg;
  50     List<DataObject> list = new CopyOnWriteArrayList<DataObject>();
  51 ---------------------------------------------------------------------------
  52
  53 Do your transation work and return
  54
  55 -------------------------------------------------------------
  56 PacketReceived pktInEvent = pktInBuilder.build();
  57 list.add(pktInEvent);
  58 return list;
  59 -------------------------------------------------------------
  60
  61 [[register-your-translator-class]]
  62 ===== Register your Translator Class
  63
  64 Next you need to go to
  65 https://git.opendaylight.org/gerrit/gitweb?p=openflowplugin.git;a=blob;f=openflowplugin/src/main/java/org/opendaylight/openflowplugin/openflow/md/core/MDController.java;hb=refs/heads/stable/boron[MDController.java]
  66 and in init() add register your Translator:
  67
  68 -----------------------------------------------------------------------------------
  69 public void init() {
  70         LOG.debug("Initializing!");
  71         messageTranslators = new ConcurrentHashMap<>();
  72         popListeners = new ConcurrentHashMap<>();
  73         //TODO: move registration to factory
  74         addMessageTranslator(ErrorMessage.class, OF10, new ErrorTranslator());
  75         addMessageTranslator(ErrorMessage.class, OF13, new ErrorTranslator());
  76         addMessageTranslator(PacketInMessage.class,OF10, new PacketInTranslator());
  77         addMessageTranslator(PacketInMessage.class,OF13, new PacketInTranslator());
  78 -----------------------------------------------------------------------------------
  79
  80 Notice that there is a separate registration for each of OpenFlow 1.0 and OpenFlow 1.3.
  81 Basically, you indicate the type of OpenFlow Protocol Library message you wish to
  82 translate for, the OpenFlow version, and an instance of your Translator.
  83
  84 [[register-your-md-sal-message-for-notification-to-the-md-sal]]
  85 ===== Register your MD-SAL Message for Notification to the MD-SAL
  86
  87 Now, also in MDController.init() register to have the
  88 notificationPopListener handle your MD-SAL Message:
  89
  90 ---------------------------------------------------------------------------------------
  91 addMessagePopListener(PacketReceived.class, new NotificationPopListener<DataObject>());
  92 ---------------------------------------------------------------------------------------
  93
  94 [[you-are-done]]
  95 ===== You are done
  96
  97 That's all there is to it. Now when a message comes up from the
  98 OpenFlow Protocol Library, it will be translated and published to the MD-SAL.