//
// Copyright (c) 2009 INESC Porto
//
// 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: Gustavo J. A. M. Carneiro  <gjc@inescporto.pt> <gjcarneiro@gmail.com>
// Modifications: Tommaso Pecorella <tommaso.pecorella@unifi.it>
//

#ifndef IPV6_FLOW_CLASSIFIER_H
#define IPV6_FLOW_CLASSIFIER_H

#include "flow-classifier.h"

#include "ns3/ipv6-header.h"

#include <map>
#include <stdint.h>

namespace ns3
{

class Packet;

/// Classifies packets by looking at their IP and TCP/UDP headers.
/// From these packet headers, a tuple (source-ip, destination-ip,
/// protocol, source-port, destination-port) is created, and a unique
/// flow identifier is assigned for each different tuple combination
class Ipv6FlowClassifier : public FlowClassifier
{
  public:
    /// Structure to classify a packet
    struct FiveTuple
    {
        Ipv6Address sourceAddress;      //!< Source address
        Ipv6Address destinationAddress; //!< Destination address
        uint8_t protocol;               //!< Protocol
        uint16_t sourcePort;            //!< Source port
        uint16_t destinationPort;       //!< Destination port
    };

    Ipv6FlowClassifier();

    /// \brief try to classify the packet into flow-id and packet-id
    ///
    /// \warning: it must be called only once per packet, from SendOutgoingLogger.
    ///
    /// \return true if the packet was classified, false if not (i.e. it
    /// does not appear to be part of a flow).
    /// \param ipHeader packet's IP header
    /// \param ipPayload packet's IP payload
    /// \param out_flowId packet's FlowId
    /// \param out_packetId packet's identifier
    bool Classify(const Ipv6Header& ipHeader,
                  Ptr<const Packet> ipPayload,
                  uint32_t* out_flowId,
                  uint32_t* out_packetId);

    /// Searches for the FiveTuple corresponding to the given flowId
    /// \param flowId the FlowId to search for
    /// \returns the FiveTuple corresponding to flowId
    FiveTuple FindFlow(FlowId flowId) const;

    /// Comparator used to sort the vector of DSCP values
    class SortByCount
    {
      public:
        /// Comparator function
        /// \param left left operand
        /// \param right right operand
        /// \return true if left DSCP is greater than right DSCP
        bool operator()(std::pair<Ipv6Header::DscpType, uint32_t> left,
                        std::pair<Ipv6Header::DscpType, uint32_t> right);
    };

    /// \brief get the DSCP values of the packets belonging to the flow with the
    /// given FlowId, sorted in decreasing order of number of packets seen with
    /// that DSCP value
    /// \param flowId the identifier of the flow of interest
    /// \returns the vector of DSCP values
    std::vector<std::pair<Ipv6Header::DscpType, uint32_t>> GetDscpCounts(FlowId flowId) const;

    void SerializeToXmlStream(std::ostream& os, uint16_t indent) const override;

  private:
    /// Map to Flows Identifiers to FlowIds
    std::map<FiveTuple, FlowId> m_flowMap;
    /// Map to FlowIds to FlowPacketId
    std::map<FlowId, FlowPacketId> m_flowPktIdMap;
    /// Map FlowIds to (DSCP value, packet count) pairs
    std::map<FlowId, std::map<Ipv6Header::DscpType, uint32_t>> m_flowDscpMap;
};

/**
 * \brief Less than operator.
 *
 * \param t1 the first operand
 * \param t2 the first operand
 * \returns true if the operands are equal
 */
bool operator<(const Ipv6FlowClassifier::FiveTuple& t1, const Ipv6FlowClassifier::FiveTuple& t2);

/**
 * \brief Equal to operator.
 *
 * \param t1 the first operand
 * \param t2 the first operand
 * \returns true if the operands are equal
 */
bool operator==(const Ipv6FlowClassifier::FiveTuple& t1, const Ipv6FlowClassifier::FiveTuple& t2);

} // namespace ns3

#endif /* IPV6_FLOW_CLASSIFIER_H */
