fq-codel-queue-disc.h

Go to the documentation of this file.

/*
 * Copyright (c) 2016 Universita' degli Studi di Napoli Federico II
 *
 * SPDX-License-Identifier: GPL-2.0-only
 *
 * Authors: Pasquale Imputato <p.imputato@gmail.com>
 *          Stefano Avallone <stefano.avallone@unina.it>
 */
 
#ifndef FQ_CODEL_QUEUE_DISC
#define FQ_CODEL_QUEUE_DISC
 
#include "queue-disc.h"
 
#include "ns3/object-factory.h"
 
#include <list>
#include <map>
 
namespace ns3
{
 
/**
 * \ingroup traffic-control
 *
 * \brief A flow queue used by the FqCoDel queue disc
 */
 
class FqCoDelFlow : public QueueDiscClass
{
  public:
    /**
     * \brief Get the type ID.
     * \return the object TypeId
     */
    static TypeId GetTypeId();
    /**
     * \brief FqCoDelFlow constructor
     */
    FqCoDelFlow();
 
    ~FqCoDelFlow() override;
 
    /**
     * \enum FlowStatus
     * \brief Used to determine the status of this flow queue
     */
    enum FlowStatus
    {
        INACTIVE,
        NEW_FLOW,
        OLD_FLOW
    };
 
    /**
     * \brief Set the deficit for this flow
     * \param deficit the deficit for this flow
     */
    void SetDeficit(uint32_t deficit);
    /**
     * \brief Get the deficit for this flow
     * \return the deficit for this flow
     */
    int32_t GetDeficit() const;
    /**
     * \brief Increase the deficit for this flow
     * \param deficit the amount by which the deficit is to be increased
     */
    void IncreaseDeficit(int32_t deficit);
    /**
     * \brief Set the status for this flow
     * \param status the status for this flow
     */
    void SetStatus(FlowStatus status);
    /**
     * \brief Get the status of this flow
     * \return the status of this flow
     */
    FlowStatus GetStatus() const;
    /**
     * \brief Set the index for this flow
     * \param index the index for this flow
     */
    void SetIndex(uint32_t index);
    /**
     * \brief Get the index of this flow
     * \return the index of this flow
     */
    uint32_t GetIndex() const;
 
  private:
    int32_t m_deficit;   //!< the deficit for this flow
    FlowStatus m_status; //!< the status of this flow
    uint32_t m_index;    //!< the index for this flow
};
 
/**
 * \ingroup traffic-control
 *
 * \brief A FqCoDel packet queue disc
 */
 
class FqCoDelQueueDisc : public QueueDisc
{
  public:
    /**
     * \brief Get the type ID.
     * \return the object TypeId
     */
    static TypeId GetTypeId();
    /**
     * \brief FqCoDelQueueDisc constructor
     */
    FqCoDelQueueDisc();
 
    ~FqCoDelQueueDisc() override;
 
    /**
     * \brief Set the quantum value.
     *
     * \param quantum The number of bytes each queue gets to dequeue on each round of the scheduling
     * algorithm
     */
    void SetQuantum(uint32_t quantum);
 
    /**
     * \brief Get the quantum value.
     *
     * \returns The number of bytes each queue gets to dequeue on each round of the scheduling
     * algorithm
     */
    uint32_t GetQuantum() const;
 
    // Reasons for dropping packets
    static constexpr const char* UNCLASSIFIED_DROP =
        "Unclassified drop"; //!< No packet filter able to classify packet
    static constexpr const char* OVERLIMIT_DROP = "Overlimit drop"; //!< Overlimit dropped packets
 
  private:
    bool DoEnqueue(Ptr<QueueDiscItem> item) override;
    Ptr<QueueDiscItem> DoDequeue() override;
    bool CheckConfig() override;
    void InitializeParams() override;
 
    /**
     * \brief Drop a packet from the head of the queue with the largest current byte count
     * \return the index of the queue with the largest current byte count
     */
    uint32_t FqCoDelDrop();
 
    bool m_useEcn; //!< True if ECN is used (packets are marked instead of being dropped)
    /**
     * Compute the index of the queue for the flow having the given flowHash,
     * according to the set associative hash approach.
     *
     * \param flowHash the hash of the flow 5-tuple
     * \return the index of the queue for the given flow
     */
    uint32_t SetAssociativeHash(uint32_t flowHash);
 
    std::string m_interval;          //!< CoDel interval attribute
    std::string m_target;            //!< CoDel target attribute
    uint32_t m_quantum;              //!< Deficit assigned to flows at each round
    uint32_t m_flows;                //!< Number of flow queues
    uint32_t m_setWays;              //!< size of a set of queues (used by set associative hash)
    uint32_t m_dropBatchSize;        //!< Max number of packets dropped from the fat flow
    uint32_t m_perturbation;         //!< hash perturbation value
    Time m_ceThreshold;              //!< Threshold above which to CE mark
    bool m_enableSetAssociativeHash; //!< whether to enable set associative hash
    bool m_useL4s; //!< True if L4S is used (ECT1 packets are marked at CE threshold)
 
    std::list<Ptr<FqCoDelFlow>> m_newFlows; //!< The list of new flows
    std::list<Ptr<FqCoDelFlow>> m_oldFlows; //!< The list of old flows
 
    std::map<uint32_t, uint32_t> m_flowsIndices; //!< Map with the index of class for each flow
    std::map<uint32_t, uint32_t> m_tags;         //!< Tags used by set associative hash
 
    ObjectFactory m_flowFactory;      //!< Factory to create a new flow
    ObjectFactory m_queueDiscFactory; //!< Factory to create a new queue
};
 
} // namespace ns3
 
#endif /* FQ_CODEL_QUEUE_DISC */