/**
   * Pushes a packet-out to a switch. The assumption here is that the packet-in was also generated
   * from the same switch. Thus, if the input port of the packet-in and the outport are the same,
   * the function will not push the packet-out.
   *
   * @param sw switch that generated the packet-in, and from which packet-out is sent
   * @param pi packet-in
   * @param useBufferId if true, use the bufferId from the packet in and do not add the packetIn's
   *     payload. If false set bufferId to BUFFER_ID_NONE and use the packetIn's payload
   * @param outport output port
   * @param cntx context of the packet
   */
  protected void pushPacket(
      IOFSwitch sw, OFPacketIn pi, boolean useBufferId, short outport, FloodlightContext cntx) {

    if (pi == null) {
      return;
    }

    // The assumption here is (sw) is the switch that generated the
    // packet-in. If the input port is the same as output port, then
    // the packet-out should be ignored.
    if (pi.getInPort() == outport) {
      if (log.isDebugEnabled()) {
        log.debug(
            "Attempting to do packet-out to the same "
                + "interface as packet-in. Dropping packet. "
                + " SrcSwitch={}, pi={}",
            new Object[] {sw, pi});
        return;
      }
    }

    if (log.isTraceEnabled()) {
      log.trace("PacketOut srcSwitch={} pi={}", new Object[] {sw, pi});
    }

    OFPacketOut po =
        (OFPacketOut) floodlightProvider.getOFMessageFactory().getMessage(OFType.PACKET_OUT);

    // set actions
    List<OFAction> actions = new ArrayList<OFAction>();
    actions.add(new OFActionOutput(outport, (short) 0xffff));

    po.setActions(actions).setActionsLength((short) OFActionOutput.MINIMUM_LENGTH);
    short poLength = (short) (po.getActionsLength() + OFPacketOut.MINIMUM_LENGTH);

    if (useBufferId) {
      po.setBufferId(pi.getBufferId());
    } else {
      po.setBufferId(OFPacketOut.BUFFER_ID_NONE);
    }

    if (po.getBufferId() == OFPacketOut.BUFFER_ID_NONE) {
      byte[] packetData = pi.getPacketData();
      poLength += packetData.length;
      po.setPacketData(packetData);
    }

    po.setInPort(pi.getInPort());
    po.setLength(poLength);

    try {
      counterStore.updatePktOutFMCounterStoreLocal(sw, po);
      messageDamper.write(sw, po, cntx);
    } catch (IOException e) {
      log.error("Failure writing packet out", e);
    }
  }
  /**
   * Pushes a packet-out to a switch. If bufferId != BUFFER_ID_NONE we assume that the packetOut
   * switch is the same as the packetIn switch and we will use the bufferId. In this case the packet
   * can be null Caller needs to make sure that inPort and outPort differs
   *
   * @param packet packet data to send.
   * @param sw switch from which packet-out is sent
   * @param bufferId bufferId
   * @param inPort input port
   * @param outPort output port
   * @param cntx context of the packet
   * @param flush force to flush the packet.
   */
  @LogMessageDocs({
    @LogMessageDoc(
        level = "ERROR",
        message =
            "BufferId is not and packet data is null. "
                + "Cannot send packetOut. "
                + "srcSwitch={dpid} inPort={port} outPort={port}",
        explanation = "The switch send a malformed packet-in." + "The packet will be dropped",
        recommendation = LogMessageDoc.REPORT_SWITCH_BUG),
    @LogMessageDoc(
        level = "ERROR",
        message = "Failure writing packet out",
        explanation = "An I/O error occurred while writing a " + "packet out to a switch",
        recommendation = LogMessageDoc.CHECK_SWITCH)
  })
  public void pushPacket(
      IPacket packet,
      IOFSwitch sw,
      int bufferId,
      short inPort,
      short outPort,
      FloodlightContext cntx,
      boolean flush) {

    if (log.isTraceEnabled()) {
      log.trace("PacketOut srcSwitch={} inPort={} outPort={}", new Object[] {sw, inPort, outPort});
    }

    OFPacketOut po =
        (OFPacketOut) floodlightProvider.getOFMessageFactory().getMessage(OFType.PACKET_OUT);

    // set actions
    List<OFAction> actions = new ArrayList<OFAction>();
    actions.add(new OFActionOutput(outPort, (short) 0xffff));

    po.setActions(actions).setActionsLength((short) OFActionOutput.MINIMUM_LENGTH);
    short poLength = (short) (po.getActionsLength() + OFPacketOut.MINIMUM_LENGTH);

    // set buffer_id, in_port
    po.setBufferId(bufferId);
    po.setInPort(inPort);

    // set data - only if buffer_id == -1
    if (po.getBufferId() == OFPacketOut.BUFFER_ID_NONE) {
      if (packet == null) {
        log.error(
            "BufferId is not set and packet data is null. "
                + "Cannot send packetOut. "
                + "srcSwitch={} inPort={} outPort={}",
            new Object[] {sw, inPort, outPort});
        return;
      }
      byte[] packetData = packet.serialize();
      poLength += packetData.length;
      po.setPacketData(packetData);
    }

    po.setLength(poLength);

    try {
      counterStore.updatePktOutFMCounterStoreLocal(sw, po);
      messageDamper.write(sw, po, cntx, flush);
    } catch (IOException e) {
      log.error("Failure writing packet out", e);
    }
  }