ipv6-pmtu-cache.h

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/*
 * Copyright (c) 2013 Universita' di Firenze
 *
 * SPDX-License-Identifier: GPL-2.0-only
 *
 * Author: Tommaso Pecorella <tommaso.pecorella@unifi.it>
 */
 
#ifndef IPV6_PMTU_CACHE_H
#define IPV6_PMTU_CACHE_H
 
#include "ns3/event-id.h"
#include "ns3/ipv6-address.h"
#include "ns3/nstime.h"
#include "ns3/object.h"
#include "ns3/type-id.h"
 
#include <map>
 
namespace ns3
{
 
/**
 * \ingroup ipv6
 *
 * \brief This class implements the Path MTU cache, as defined by \RFC{1981}.
 *
 * The Path MTU is stored according to the destination address, and it is
 * cleared upon expiration (default validity time is 10 minutes).
 *
 * The "infinite lifetime" PMTU entry type is not implemented, since it is
 * useful only in an very limited number of cases. See the RFC for further
 * details.
 */
 
class Ipv6PmtuCache : public Object
{
  public:
    class Entry;
 
    /**
     * \brief Get the type ID
     * \return type ID
     */
    static TypeId GetTypeId();
 
    /**
     * \brief Constructor.
     */
    Ipv6PmtuCache();
 
    /**
     * \brief Destructor.
     */
    ~Ipv6PmtuCache() override;
 
    /**
     * \brief Dispose object.
     */
    void DoDispose() override;
 
    /**
     * \brief Gets the known Path MTU for the specific destination
     * \param dst the destination
     * \return the Path MTU (zero if unknown)
     */
    uint32_t GetPmtu(Ipv6Address dst);
 
    /**
     * \brief Sets the Path MTU for the specific destination
     * \param dst the destination
     * \param pmtu the Path MTU
     */
    void SetPmtu(Ipv6Address dst, uint32_t pmtu);
 
    /**
     * \brief Gets the Path MTU validity time
     * \return the Path MTU validity time
     */
    Time GetPmtuValidityTime() const;
 
    /**
     * \brief Sets the Path MTU validity time (minimum is 5 minutes)
     * \param validity the Path MTU validity time
     * \return true if the change was successful
     */
    bool SetPmtuValidityTime(Time validity);
 
  private:
    /**
     * \brief Clears the Path MTU for the specific destination
     * \param dst the destination
     */
    void ClearPmtu(Ipv6Address dst);
 
    /**
     * \brief Path MTU table
     */
    std::map<Ipv6Address, uint32_t> m_pathMtu;
 
    /**
     * \brief Container of the IPv6 PMTU data (Ipv6 destination address and expiration event).
     */
    typedef std::map<Ipv6Address, EventId>::iterator pathMtuTimerIter;
 
    /**
     * \brief Path MTU Expiration table
     */
    std::map<Ipv6Address, EventId> m_pathMtuTimer;
 
    /**
     * \brief Path MTU entry validity time
     */
    Time m_validityTime;
};
 
} // namespace ns3
 
#endif /* IPV6_PMTU_CACHE_H */