network: Get rid of the NetDeviceQueue::HasWakeCallbackSet method

src/network/model/net-device.cc

@@ -118,12 +118,6 @@ NetDeviceQueue::SetWakeCallback (WakeCallback cb)
   m_wakeCallback = cb;
 }
 
-bool
-NetDeviceQueue::HasWakeCallbackSet (void) const
-{
-  return (!m_wakeCallback.IsNull ());
-}
-
 
 NS_OBJECT_ENSURE_REGISTERED (NetDeviceQueueInterface);
 
@@ -137,10 +131,9 @@ TypeId NetDeviceQueueInterface::GetTypeId (void)
 }
 
 NetDeviceQueueInterface::NetDeviceQueueInterface ()
+  : m_numTxQueues (1)
 {
   NS_LOG_FUNCTION (this);
-  Ptr<NetDeviceQueue> devQueue = Create<NetDeviceQueue> ();
-  m_txQueuesVector.push_back (devQueue);
 }
 
 NetDeviceQueueInterface::~NetDeviceQueueInterface ()
@@ -172,21 +165,27 @@ NetDeviceQueueInterface::DoDispose (void)
 void
 NetDeviceQueueInterface::SetTxQueuesN (uint8_t numTxQueues)
 {
+  NS_LOG_FUNCTION (this << numTxQueues);
   NS_ASSERT (numTxQueues > 0);
 
-  // check whether a queue disc has been installed on the device by
-  // verifying whether a wake callback has been set on a transmission queue
-  NS_ABORT_MSG_IF (GetTxQueue (0)->HasWakeCallbackSet (), "Cannot change the number of"
-                   " transmission queues after setting up the wake callback.");
+  NS_ABORT_MSG_IF (m_txQueuesVector.size (), "Cannot change the number of"
+                   " device transmission queues once they have been created.");
 
-  uint8_t prevNumTxQueues = m_txQueuesVector.size ();
-  m_txQueuesVector.resize (numTxQueues);
+  m_numTxQueues = numTxQueues;
+}
 
-  // Allocate new NetDeviceQueues if the number of queues increased
-  for (uint8_t i = prevNumTxQueues; i < numTxQueues; i++)
+void
+NetDeviceQueueInterface::CreateTxQueues (void)
+{
+  NS_LOG_FUNCTION (this);
+
+  NS_ABORT_MSG_IF (m_txQueuesVector.size (), "The device transmission queues"
+                   " have been already created.");
+
+  for (uint8_t i = 0; i < m_numTxQueues; i++)
     {
       Ptr<NetDeviceQueue> devQueue = Create<NetDeviceQueue> ();
-      m_txQueuesVector[i] = devQueue;
+      m_txQueuesVector.push_back (devQueue);
     }
 }
 

src/network/model/net-device.h

@@ -165,27 +165,27 @@ public:
   virtual ~NetDeviceQueue();
 
   /**
-   * Called by the device to start this (hardware) transmission queue.
+   * Called by the device to start this device transmission queue.
    * This is the analogous to the netif_tx_start_queue function of the Linux kernel.
    */
   virtual void Start (void);
 
   /**
-   * Called by the device to stop this (hardware) transmission queue.
+   * Called by the device to stop this device transmission queue.
    * This is the analogous to the netif_tx_stop_queue function of the Linux kernel.
    */
   virtual void Stop (void);
 
   /**
    * Called by the device to wake the queue disc associated with this
-   * (hardware) transmission queue. This is done by invoking the wake callback.
+   * device transmission queue. This is done by invoking the wake callback.
    * This is the analogous to the netif_tx_wake_queue function of the Linux kernel.
    */
   virtual void Wake (void);
 
   /**
    * \brief Get the status of the device transmission queue.
-   * \return true if the (hardware) transmission queue is stopped.
+   * \return true if the device transmission queue is stopped.
    *
    * Called by queue discs to enquire about the status of a given transmission queue.
    * This is the analogous to the netif_tx_queue_stopped function of the Linux kernel.
@@ -207,12 +207,6 @@ public:
    */
   virtual void SetWakeCallback (WakeCallback cb);
 
-  /**
-   * \brief Check whether a wake callback has been set on this device queue.
-   * \return true if the wake callback has been set.
-   */
-  virtual bool HasWakeCallbackSet (void) const;
-
 private:
   bool m_stopped;   //!< Status of the transmission queue
   WakeCallback m_wakeCallback;   //!< Wake callback
@@ -224,15 +218,15 @@ private:
  *
  * \brief Network device transmission queue interface
  *
- * This interface is required by the traffic control layer to access the information
- * about the status of the transmission queues of a device. Thus, every NetDevice
- * (but loopback) needs to create this interface. NetDevices supporting flow control
- * can start and stop their device transmission queues and wake the upper layers through
- * this interface. By default, a NetDeviceQueueInterface object is created with a single
- * device transmission queue. Therefore, multi-queue devices need to call SetTxQueuesN
- * to create additional queues (before a root queue disc is installed, i.e., typically
- * before an IPv4/IPv6 address is assigned to the device), implement a GetSelectedQueue
- * method and pass a callback to such a method through the SetSelectedQueueCallback method.
+ * This interface is used by the traffic control layer and by the aggregated
+ * device to access the transmission queues of the device. Additionally, through
+ * this interface, traffic control aware netdevices can:
+ * - set the number of transmission queues
+ * - set the method used (by upper layers) to determine the transmission queue
+ *   in which the netdevice would enqueue a given packet
+ * This interface is created and aggregated to a device by the traffic control
+ * layer when an Ipv{4,6}Interface is added to the device or a queue disc is
+ * installed on the device.
  */
 class NetDeviceQueueInterface : public Object
 {
@@ -268,16 +262,23 @@ public:
   uint8_t GetNTxQueues (void) const;
 
   /**
-   * \brief Set the number of device transmission queues.
-   * \param numTxQueues number of device transmission queues.
+   * \brief Set the number of device transmission queues to create.
+   * \param numTxQueues number of device transmission queues to create.
    *
-   * Called by a device to set the number of device transmission queues.
-   * This method can be called by a NetDevice at initialization time only, because
-   * it is not possible to change the number of device transmission queues after
-   * the wake callbacks have been set on the device queues.
+   * A multi-queue netdevice must call this method from within its
+   * NotifyNewAggregate method to set the number of device transmission queues
+   * to create.
    */
   void SetTxQueuesN (uint8_t numTxQueues);
 
+  /**
+   * \brief Create the device transmission queues.
+   *
+   * Called by the traffic control layer just after aggregating this netdevice
+   * queue interface to the netdevice.
+   */
+  void CreateTxQueues (void);
+
   /// Callback invoked to determine the tx queue selected for a given packet
   typedef Callback< uint8_t, Ptr<QueueItem> > SelectQueueCallback;
 
@@ -285,7 +286,8 @@ public:
    * \brief Set the select queue callback.
    * \param cb the callback to set.
    *
-   * Called by a multi-queue device to set the select queue callback, i.e., the
+   * A multi-queue netdevice must call this method from within its
+   * NotifyNewAggregate method to set the select queue callback, i.e., the
    * method used to select a device transmission queue for a given packet.
    */
   void SetSelectQueueCallback (SelectQueueCallback cb);
@@ -308,6 +310,7 @@ protected:
 private:
   std::vector< Ptr<NetDeviceQueue> > m_txQueuesVector;   //!< Device transmission queues
   SelectQueueCallback m_selectQueueCallback;   //!< Select queue callback
+  uint8_t m_numTxQueues;   //!< Number of transmission queues to create
 };
 
 

src/point-to-point/test/point-to-point-test.cc

@@ -88,8 +88,10 @@ PointToPointTest::DoRun (void)
 
   Ptr<NetDeviceQueueInterface> ifaceA = CreateObject<NetDeviceQueueInterface> ();
   devA->AggregateObject (ifaceA);
+  ifaceA->CreateTxQueues ();
   Ptr<NetDeviceQueueInterface> ifaceB = CreateObject<NetDeviceQueueInterface> ();
   devB->AggregateObject (ifaceB);
+  ifaceB->CreateTxQueues ();
 
   Simulator::Schedule (Seconds (1.0), &PointToPointTest::SendOnePacket, this, devA);
 

src/traffic-control/model/traffic-control-layer.cc

@@ -128,6 +128,11 @@ TrafficControlLayer::SetupDevice (Ptr<NetDevice> device)
   Ptr<NetDeviceQueueInterface> devQueueIface = CreateObject<NetDeviceQueueInterface> ();
   device->AggregateObject (devQueueIface);
 
+  // multi-queue devices must set the number of transmission queues in their
+  // NotifyNewAggregate method. Since we have just aggregated the netdevice
+  // queue interface to the device, we can create the transmission queues
+  devQueueIface->CreateTxQueues ();
+
   // devices can set a select queue callback in their NotifyNewAggregate method
   SelectQueueCallback cb = devQueueIface->GetSelectQueueCallback ();