net-device-queue-interface.h

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/*
 * 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 "ns3/callback.h"
#include "ns3/log.h"
#include "ns3/net-device.h"
#include "ns3/object-factory.h"
#include "ns3/object.h"
#include "ns3/ptr.h"
#include "ns3/simulator.h"
 
#include <functional>
#include <vector>
 
namespace ns3
{
 
class QueueLimits;
class NetDeviceQueueInterface;
class QueueItem;
 
class NetDeviceQueue : public Object
{
  public:
    static TypeId GetTypeId();
 
    NetDeviceQueue();
    ~NetDeviceQueue() override;
 
    virtual void Start();
 
    virtual void Stop();
 
    virtual void Wake();
 
    virtual bool IsStopped() 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();
 
    NetDeviceQueueInterface();
    ~NetDeviceQueueInterface() override;
 
    Ptr<NetDeviceQueue> GetTxQueue(std::size_t i) const;
 
    std::size_t GetNTxQueues() 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() const;
 
  protected:
    void DoDispose() override;
    void NotifyNewAggregate() override;
 
  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);
 
    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");
    // 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->WouldOverflow(1, m_device->GetMtu()))
    {
        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);
    NS_ASSERT_MSG(m_device, "Aggregated NetDevice not set");
 
    Simulator::ScheduleNow([=, this]() {
        // Inform BQL
        NotifyTransmittedBytes(item->GetSize());
 
        // 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->WouldOverflow(1, m_device->GetMtu()))
        {
            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 */