net-device-queue-interface.h

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2017 Universita' degli Studi di Napoli Federico II
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation;
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Author: Stefano Avallone <stefano.avallone@.unina.it>
 */
#ifndef NET_DEVICE_QUEUE_INTERFACE_H
#define NET_DEVICE_QUEUE_INTERFACE_H

#include <vector>
#include <functional>
#include "ns3/callback.h"
#include "ns3/object.h"
#include "ns3/ptr.h"
#include "ns3/log.h"
#include "ns3/net-device.h"
#include "ns3/object-factory.h"

namespace ns3 {

class QueueLimits;
class NetDeviceQueueInterface;
class QueueItem;


class NetDeviceQueue : public Object
{
public:
  static TypeId GetTypeId (void);

  NetDeviceQueue ();
  virtual ~NetDeviceQueue();

  virtual void Start (void);

  virtual void Stop (void);

  virtual void Wake (void);

  virtual bool IsStopped (void) const;

  void NotifyAggregatedObject (Ptr<NetDeviceQueueInterface> ndqi);

  typedef Callback< void > WakeCallback;

  virtual void SetWakeCallback (WakeCallback cb);

  virtual void NotifyQueuedBytes (uint32_t bytes);

  virtual void NotifyTransmittedBytes (uint32_t bytes);

  void ResetQueueLimits ();

  void SetQueueLimits (Ptr<QueueLimits> ql);

  Ptr<QueueLimits> GetQueueLimits ();

  template <typename QueueType>
  void PacketEnqueued (QueueType* queue, Ptr<const typename QueueType::ItemType> item);

  template <typename QueueType>
  void PacketDequeued (QueueType* queue, Ptr<const typename QueueType::ItemType> item);

  template <typename QueueType>
  void PacketDiscarded (QueueType* queue, Ptr<const typename QueueType::ItemType> item);

  template <typename QueueType>
  void ConnectQueueTraces (Ptr<QueueType> queue);

private:
  bool m_stoppedByDevice;         
  bool m_stoppedByQueueLimits;    
  Ptr<QueueLimits> m_queueLimits; 
  WakeCallback m_wakeCallback;    
  Ptr<NetDevice> m_device;        

  NS_LOG_TEMPLATE_DECLARE;        
};


class NetDeviceQueueInterface : public Object
{
public:
  static TypeId GetTypeId (void);

  NetDeviceQueueInterface ();
  virtual ~NetDeviceQueueInterface ();

  Ptr<NetDeviceQueue> GetTxQueue (std::size_t i) const;

  std::size_t GetNTxQueues (void) const;

  void SetTxQueuesType (TypeId type);

  void SetNTxQueues (std::size_t numTxQueues);

  typedef std::function<std::size_t (Ptr<QueueItem>)> SelectQueueCallback;

  void SetSelectQueueCallback (SelectQueueCallback cb);

  SelectQueueCallback GetSelectQueueCallback (void) const;

protected:
  virtual void DoDispose (void);
  virtual void NotifyNewAggregate (void);

private:
  ObjectFactory m_txQueues;   
  std::vector< Ptr<NetDeviceQueue> > m_txQueuesVector;   
  SelectQueueCallback m_selectQueueCallback;   
};


template <typename QueueType>
void
NetDeviceQueue::ConnectQueueTraces (Ptr<QueueType> queue)
{
  NS_ASSERT (queue != 0);

  queue->TraceConnectWithoutContext ("Enqueue",
                                     MakeCallback (&NetDeviceQueue::PacketEnqueued<QueueType>, this)
                                     .Bind (PeekPointer (queue)));
  queue->TraceConnectWithoutContext ("Dequeue",
                                     MakeCallback (&NetDeviceQueue::PacketDequeued<QueueType>, this)
                                     .Bind (PeekPointer (queue)));
  queue->TraceConnectWithoutContext ("DropBeforeEnqueue",
                                     MakeCallback (&NetDeviceQueue::PacketDiscarded<QueueType>, this)
                                     .Bind (PeekPointer (queue)));
}

template <typename QueueType>
void
NetDeviceQueue::PacketEnqueued (QueueType* queue, Ptr<const typename QueueType::ItemType> item)
{
  NS_LOG_FUNCTION (this << queue << item);

  // Inform BQL
  NotifyQueuedBytes (item->GetSize ());

  NS_ASSERT_MSG (m_device, "Aggregated NetDevice not set");
  Ptr<Packet> p = Create<Packet> (m_device->GetMtu ());

  // After enqueuing a packet, we need to check whether the queue is able to
  // store another packet. If not, we stop the queue

  if (queue->GetCurrentSize () + p > queue->GetMaxSize ())
    {
      NS_LOG_DEBUG ("The device queue is being stopped (" << queue->GetCurrentSize ()
                    << " inside)");
      Stop ();
    }
}

template <typename QueueType>
void
NetDeviceQueue::PacketDequeued (QueueType* queue, Ptr<const typename QueueType::ItemType> item)
{
  NS_LOG_FUNCTION (this << queue << item);

  // Inform BQL
  NotifyTransmittedBytes (item->GetSize ());

  NS_ASSERT_MSG (m_device, "Aggregated NetDevice not set");
  Ptr<Packet> p = Create<Packet> (m_device->GetMtu ());

  // After dequeuing a packet, if there is room for another packet we
  // call Wake () that ensures that the queue is not stopped and restarts
  // the queue disc if the queue was stopped

  if (queue->GetCurrentSize () + p <= queue->GetMaxSize ())
    {
      Wake ();
    }
}

template <typename QueueType>
void
NetDeviceQueue::PacketDiscarded (QueueType* queue, Ptr<const typename QueueType::ItemType> item)
{
  NS_LOG_FUNCTION (this << queue << item);

  // This method is called when a packet is discarded before being enqueued in the
  // device queue, likely because the queue is full. This should not happen if the
  // device correctly stops the queue. Anyway, stop the tx queue, so that the upper
  // layers do not send packets until there is room in the queue again.

  NS_LOG_ERROR ("BUG! No room in the device queue for the received packet! ("
                << queue->GetCurrentSize () << " inside)");

  Stop ();
}

} // namespace ns3

#endif /* NET_DEVICE_QUEUE_INTERFACE_H */