/*
 * Copyright (c) 2005 INRIA
 *
 * SPDX-License-Identifier: GPL-2.0-only
 *
 * Author: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
 */

#ifndef IPV4_END_POINT_DEMUX_H
#define IPV4_END_POINT_DEMUX_H

#include "ipv4-interface.h"

#include "ns3/ipv4-address.h"

#include <list>
#include <stdint.h>

namespace ns3
{

class Ipv4EndPoint;

/**
 * @ingroup ipv4
 *
 * @brief Demultiplexes packets to various transport layer endpoints
 *
 * This class serves as a lookup table to match partial or full information
 * about a four-tuple to an ns3::Ipv4EndPoint.  It internally contains a list
 * of endpoints, and has APIs to add and find endpoints in this demux.  This
 * code is shared in common to TCP and UDP protocols in ns3.  This demux
 * sits between ns3's layer four and the socket layer
 */

class Ipv4EndPointDemux
{
  public:
    /**
     * @brief Container of the IPv4 endpoints.
     */
    typedef std::list<Ipv4EndPoint*> EndPoints;

    /**
     * @brief Iterator to the container of the IPv4 endpoints.
     */
    typedef std::list<Ipv4EndPoint*>::iterator EndPointsI;

    Ipv4EndPointDemux();
    ~Ipv4EndPointDemux();

    /**
     * @brief Get the entire list of end points registered.
     * @return list of Ipv4EndPoint
     */
    EndPoints GetAllEndPoints();

    /**
     * @brief Lookup for port local.
     * @param port port to test
     * @return true if a port local is in EndPoints, false otherwise
     */
    bool LookupPortLocal(uint16_t port);

    /**
     * @brief Lookup for address and port.
     * @param boundNetDevice Bound NetDevice (if any)
     * @param addr address to test
     * @param port port to test
     * @return true if there is a match in EndPoints, false otherwise
     */
    bool LookupLocal(Ptr<NetDevice> boundNetDevice, Ipv4Address addr, uint16_t port);

    /**
     * @brief lookup for a match with all the parameters.
     *
     * The function will return a list of most-matching EndPoints, in this order:
     *   -# Full match
     *   -# All but local address
     *   -# Only local port and local address match
     *   -# Only local port match
     *
     * EndPoint with disabled Rx are skipped.
     *
     * @param daddr destination address to test
     * @param dport destination port to test
     * @param saddr source address to test
     * @param sport source port to test
     * @param incomingInterface the incoming interface
     * @return list of IPv4EndPoints (could be 0 element)
     */
    EndPoints Lookup(Ipv4Address daddr,
                     uint16_t dport,
                     Ipv4Address saddr,
                     uint16_t sport,
                     Ptr<Ipv4Interface> incomingInterface);

    /**
     * @brief simple lookup for a match with all the parameters.
     * @param daddr destination address to test
     * @param dport destination port to test
     * @param saddr source address to test
     * @param sport source port to test
     * @return IPv4EndPoint (0 if not found)
     */
    Ipv4EndPoint* SimpleLookup(Ipv4Address daddr,
                               uint16_t dport,
                               Ipv4Address saddr,
                               uint16_t sport);

    /**
     * @brief Allocate a Ipv4EndPoint.
     * @return an empty Ipv4EndPoint instance
     */
    Ipv4EndPoint* Allocate();

    /**
     * @brief Allocate a Ipv4EndPoint.
     * @param address IPv4 address
     * @return an Ipv4EndPoint instance
     */
    Ipv4EndPoint* Allocate(Ipv4Address address);

    /**
     * @brief Allocate a Ipv4EndPoint.
     * @param boundNetDevice Bound NetDevice (if any)
     * @param port local port
     * @return an Ipv4EndPoint instance
     */
    Ipv4EndPoint* Allocate(Ptr<NetDevice> boundNetDevice, uint16_t port);

    /**
     * @brief Allocate a Ipv4EndPoint.
     * @param boundNetDevice Bound NetDevice (if any)
     * @param address local address
     * @param port local port
     * @return an Ipv4EndPoint instance
     */
    Ipv4EndPoint* Allocate(Ptr<NetDevice> boundNetDevice, Ipv4Address address, uint16_t port);

    /**
     * @brief Allocate a Ipv4EndPoint.
     * @param boundNetDevice Bound NetDevice (if any)
     * @param localAddress local address
     * @param localPort local port
     * @param peerAddress peer address
     * @param peerPort peer port
     * @return an Ipv4EndPoint instance
     */
    Ipv4EndPoint* Allocate(Ptr<NetDevice> boundNetDevice,
                           Ipv4Address localAddress,
                           uint16_t localPort,
                           Ipv4Address peerAddress,
                           uint16_t peerPort);

    /**
     * @brief Remove a end point.
     * @param endPoint the end point to remove
     */
    void DeAllocate(Ipv4EndPoint* endPoint);

  private:
    /**
     * @brief Allocate an ephemeral port.
     * @returns the ephemeral port
     */
    uint16_t AllocateEphemeralPort();

    /**
     * @brief The ephemeral port.
     */
    uint16_t m_ephemeral;

    /**
     * @brief The last ephemeral port.
     */
    uint16_t m_portLast;

    /**
     * @brief The first ephemeral port.
     */
    uint16_t m_portFirst;

    /**
     * @brief A list of IPv4 end points.
     */
    EndPoints m_endPoints;
};

} // namespace ns3

#endif /* IPV4_END_POINTS_H */
