// -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*-

//

// Copyright (c) 2006 Georgia Tech Research Corporation

//

// 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: George F. Riley<riley@ece.gatech.edu>

//

#ifndef IPV4_L3_PROTOCOL_H

#define IPV4_L3_PROTOCOL_H

#include <list>

#include <map>

#include <vector>

#include <stdint.h>

#include "ns3/ipv4-address.h"

#include "ns3/ptr.h"

#include "ns3/net-device.h"

#include "ns3/ipv4.h"

#include "ns3/traced-callback.h"

#include "ns3/ipv4-header.h"

#include "ns3/ipv4-routing-protocol.h"

#include "ns3/nstime.h"

#include "ns3/simulator.h"

class Ipv4L3ProtocolTestCase;

namespace ns3 {

class Packet;

class NetDevice;

class Ipv4Interface;

class Ipv4Address;

class Ipv4Header;

class Ipv4RoutingTableEntry;

class Ipv4Route;

class Node;

class Socket;

class Ipv4RawSocketImpl;

class IpL4Protocol;

class Icmpv4L4Protocol;

/**

 * \brief Implement the Ipv4 layer.

 * 

 * This is the actual implementation of IP.  It contains APIs to send and

 * receive packets at the IP layer, as well as APIs for IP routing.

 *

 * This class contains two distinct groups of trace sources.  The

 * trace sources 'Rx' and 'Tx' are called, respectively, immediately

 * after receiving from the NetDevice and immediately before sending

 * to a NetDevice for transmitting a packet.  These are low level

 * trace sources that include the Ipv4Header already serialized into

 * the packet.  In contrast, the Drop, SendOutgoing, UnicastForward,

 * and LocalDeliver trace sources are slightly higher-level and pass

 * around the Ipv4Header as an explicit parameter and not as part of

 * the packet.

 *

 * IP fragmentation and reassembly is handled at this level.

 * At the moment the fragmentation does not handle IP option headers,

 * and in particular the ones that shall not be fragmented.

 * Moreover, the actual implementation does not mimic exactly the Linux

 * kernel. Hence it is not possible, for instance, to test a fragmentation

 * attack.

 */

class Ipv4L3Protocol : public Ipv4

{

public:

  /**

   * \brief Get the type ID.

   * \return the object TypeId

   */

  static TypeId GetTypeId (void);

  static const uint16_t PROT_NUMBER; //!< Protocol number (0x0800)

  Ipv4L3Protocol();

  virtual ~Ipv4L3Protocol ();

  /**

   * \enum DropReason

   * \brief Reason why a packet has been dropped.

   */

  enum DropReason 

  {

    DROP_TTL_EXPIRED = 1,   /**< Packet TTL has expired */

    DROP_NO_ROUTE,   /**< No route to host */

    DROP_BAD_CHECKSUM,   /**< Bad checksum */

    DROP_INTERFACE_DOWN,   /**< Interface is down so can not send packet */

    DROP_ROUTE_ERROR,   /**< Route error */

    DROP_FRAGMENT_TIMEOUT /**< Fragment timeout exceeded */

  };

  /**

   * \brief Set node associated with this stack.

   * \param node node to set

   */

  void SetNode (Ptr<Node> node);

  // functions defined in base class Ipv4

  void SetRoutingProtocol (Ptr<Ipv4RoutingProtocol> routingProtocol);

  Ptr<Ipv4RoutingProtocol> GetRoutingProtocol (void) const;

  Ptr<Socket> CreateRawSocket (void);

  void DeleteRawSocket (Ptr<Socket> socket);

  /**

   * \param protocol a template for the protocol to add to this L4 Demux.

   * \returns the L4Protocol effectively added.

   *

   * Invoke Copy on the input template to get a copy of the input

   * protocol which can be used on the Node on which this L4 Demux 

   * is running. The new L4Protocol is registered internally as

   * a working L4 Protocol and returned from this method.

   * The caller does not get ownership of the returned pointer.

   */

  void Insert (Ptr<IpL4Protocol> protocol);

  /**

   * \param protocolNumber number of protocol to lookup

   *        in this L4 Demux

   * \returns a matching L4 Protocol

   *

   * This method is typically called by lower layers

   * to forward packets up the stack to the right protocol.

   */

  virtual Ptr<IpL4Protocol> GetProtocol (int protocolNumber) const;

  /**

   * \param protocol protocol to remove from this demux.

   *

   * The input value to this method should be the value

   * returned from the Ipv4L4Protocol::Insert method.

   */

  void Remove (Ptr<IpL4Protocol> protocol);

  /**

   * \param ttl default ttl to use

   *

   * When we need to send an ipv4 packet, we use this default

   * ttl value.

   */

  void SetDefaultTtl (uint8_t ttl);

  /**

   * Lower layer calls this method after calling L3Demux::Lookup

   * The ARP subclass needs to know from which NetDevice this

   * packet is coming to:

   *    - implement a per-NetDevice ARP cache

   *    - send back arp replies on the right device

   * \param device network device

   * \param p the packet

   * \param protocol protocol value

   * \param from address of the correspondant

   * \param to address of the destination

   * \param packetType type of the packet

   */

  void Receive ( Ptr<NetDevice> device, Ptr<const Packet> p, uint16_t protocol, const Address &from,

                 const Address &to, NetDevice::PacketType packetType);

  /**

   * \param packet packet to send

   * \param source source address of packet

   * \param destination address of packet

   * \param protocol number of packet

   * \param route route entry

   *

   * Higher-level layers call this method to send a packet

   * down the stack to the MAC and PHY layers.

   */

  void Send (Ptr<Packet> packet, Ipv4Address source, 

             Ipv4Address destination, uint8_t protocol, Ptr<Ipv4Route> route);

  /**

   * \param packet packet to send

   * \param ipHeader IP Header

   * \param route route entry

   *

   * Higher-level layers call this method to send a packet with IPv4 Header

   * (Intend to be used with IpHeaderInclude attribute.)

   */

  void SendWithHeader (Ptr<Packet> packet, Ipv4Header ipHeader, Ptr<Ipv4Route> route);

  uint32_t AddInterface (Ptr<NetDevice> device);

  /**

   * \brief Get an interface.

   * \param i interface index

   * \return IPv4 interface pointer

   */

  Ptr<Ipv4Interface> GetInterface (uint32_t i) const;

  uint32_t GetNInterfaces (void) const;

  int32_t GetInterfaceForAddress (Ipv4Address addr) const;

  int32_t GetInterfaceForPrefix (Ipv4Address addr, Ipv4Mask mask) const;

  int32_t GetInterfaceForDevice (Ptr<const NetDevice> device) const;

  bool IsDestinationAddress (Ipv4Address address, uint32_t iif) const;

  bool AddAddress (uint32_t i, Ipv4InterfaceAddress address);

  Ipv4InterfaceAddress GetAddress (uint32_t interfaceIndex, uint32_t addressIndex) const;

  uint32_t GetNAddresses (uint32_t interface) const;

  bool RemoveAddress (uint32_t interfaceIndex, uint32_t addressIndex);

  bool RemoveAddress (uint32_t interface, Ipv4Address address);

  Ipv4Address SelectSourceAddress (Ptr<const NetDevice> device,

                                   Ipv4Address dst, Ipv4InterfaceAddress::InterfaceAddressScope_e scope);

  void SetMetric (uint32_t i, uint16_t metric);

  uint16_t GetMetric (uint32_t i) const;

  uint16_t GetMtu (uint32_t i) const;

  bool IsUp (uint32_t i) const;

  void SetUp (uint32_t i);

  void SetDown (uint32_t i);

  bool IsForwarding (uint32_t i) const;

  void SetForwarding (uint32_t i, bool val);

  Ptr<NetDevice> GetNetDevice (uint32_t i);

  /**

   * \brief Check if an IPv4 address is unicast according to the node.

   *

   * This function checks all the node's interfaces and the respective subnet masks.

   * An address is considered unicast if it's not broadcast, subnet-broadcast or multicast.

   *

   * \param ad address

   *

   * \return true if the address is unicast

   */

  bool IsUnicast (Ipv4Address ad) const;

protected:

  virtual void DoDispose (void);

  /**

   * This function will notify other components connected to the node that a new stack member is now connected

   * This will be used to notify Layer 3 protocol of layer 4 protocol stack to connect them together.

   */

  virtual void NotifyNewAggregate ();

private:

  friend class ::Ipv4L3ProtocolTestCase;

  /**

   * \brief Copy constructor.

   *

   * Defined but not implemented to avoid misuse

   */

  Ipv4L3Protocol(const Ipv4L3Protocol &);

  /**

   * \brief Copy constructor.

   *

   * Defined but not implemented to avoid misuse

   * \returns the copied object

   */

  Ipv4L3Protocol &operator = (const Ipv4L3Protocol &);

  // class Ipv4 attributes

  virtual void SetIpForward (bool forward);

  virtual bool GetIpForward (void) const;

  virtual void SetWeakEsModel (bool model);

  virtual bool GetWeakEsModel (void) const;

  /**

   * \brief Construct an IPv4 header.

   * \param source source IPv4 address

   * \param destination destination IPv4 address

   * \param protocol L4 protocol

   * \param payloadSize payload size

   * \param ttl Time to Live

   * \param tos Type of Service

   * \param mayFragment true if the packet can be fragmented

   * \return newly created IPv4 header

   */

  Ipv4Header BuildHeader (

    Ipv4Address source,

    Ipv4Address destination,

    uint8_t protocol,

    uint16_t payloadSize,

    uint8_t ttl,

    uint8_t tos,

    bool mayFragment);

  /**

   * \brief Send packet with route.

   * \param route route

   * \param packet packet to send

   * \param ipHeader IPv4 header to add to the packet

   */

  void

  SendRealOut (Ptr<Ipv4Route> route,

               Ptr<Packet> packet,

               Ipv4Header const &ipHeader);

  /**

   * \brief Forward a packet.

   * \param rtentry route

   * \param p packet to forward

   * \param header IPv4 header to add to the packet

   */

  void 

  IpForward (Ptr<Ipv4Route> rtentry, 

             Ptr<const Packet> p, 

             const Ipv4Header &header);

  /**

   * \brief Forward a multicast packet.

   * \param mrtentry route

   * \param p packet to forward

   * \param header IPv6 header to add to the packet

   */

  void

  IpMulticastForward (Ptr<Ipv4MulticastRoute> mrtentry, 

                      Ptr<const Packet> p, 

                      const Ipv4Header &header);

  /**

   * \brief Deliver a packet.

   * \param p packet delivered

   * \param ip IPv4 header

   * \param iif input interface packet was received

   */

  void LocalDeliver (Ptr<const Packet> p, Ipv4Header const&ip, uint32_t iif);

  /**

   * \brief Fallback when no route is found.

   * \param p packet

   * \param ipHeader IPv4 header

   * \param sockErrno error number

   */

  void RouteInputError (Ptr<const Packet> p, const Ipv4Header & ipHeader, Socket::SocketErrno sockErrno);

  /**

   * \brief Add an IPv4 interface to the stack.

   * \param interface interface to add

   * \return index of newly added interface

   */

  uint32_t AddIpv4Interface (Ptr<Ipv4Interface> interface);

  /**

   * \brief Setup loopback interface.

   */

  void SetupLoopback (void);

  /**

   * \brief Get ICMPv4 protocol.

   * \return Icmpv4L4Protocol pointer

   */

  Ptr<Icmpv4L4Protocol> GetIcmp (void) const;

  /**

   * \brief Check if an IPv4 address is unicast.

   * \param ad address

   * \param interfaceMask the network mask

   * \return true if the address is unicast

   */

  bool IsUnicast (Ipv4Address ad, Ipv4Mask interfaceMask) const;

  /**

   * \brief Fragment a packet

   * \param packet the packet

   * \param outIfaceMtu the MTU of the interface

   * \param listFragments the list of fragments

   */

  void DoFragmentation (Ptr<Packet> packet, uint32_t outIfaceMtu, std::list<Ptr<Packet> >& listFragments);

  /**

   * \brief Process a packet fragment

   * \param packet the packet

   * \param ipHeader the IP header

   * \param iif Input Interface

   * \return true is the fragment completed the packet

   */

  bool ProcessFragment (Ptr<Packet>& packet, Ipv4Header & ipHeader, uint32_t iif);

  /**

   * \brief Process the timeout for packet fragments

   * \param key representing the packet fragments

   * \param ipHeader the IP header of the original packet

   * \param iif Input Interface

   */

  void HandleFragmentsTimeout ( std::pair<uint64_t, uint32_t> key, Ipv4Header & ipHeader, uint32_t iif);

  /**

   * \brief Container of the IPv4 Interfaces.

   */

  typedef std::vector<Ptr<Ipv4Interface> > Ipv4InterfaceList;

  /**

   * \brief Container of the IPv4 Raw Sockets.

   */

  typedef std::list<Ptr<Ipv4RawSocketImpl> > SocketList;

  /**

   * \brief Container of the IPv4 L4 instances.

   */

   typedef std::list<Ptr<IpL4Protocol> > L4List_t;

  bool m_ipForward;      //!< Forwarding packets (i.e. router mode) state.

  bool m_weakEsModel;    //!< Weak ES model state

  L4List_t m_protocols;  //!< List of transport protocol.

  Ipv4InterfaceList m_interfaces; //!< List of IPv4 interfaces.

  uint8_t m_defaultTos;  //!< Default TOS

  uint8_t m_defaultTtl;  //!< Default TTL

  std::map<std::pair<uint64_t, uint8_t>, uint16_t> m_identification; //!< Identification (for each {src, dst, proto} tuple)

  Ptr<Node> m_node; //!< Node attached to stack.

  /// Trace of sent packets

  TracedCallback<const Ipv4Header &, Ptr<const Packet>, uint32_t> m_sendOutgoingTrace;

  /// Trace of unicast forwarded packets

  TracedCallback<const Ipv4Header &, Ptr<const Packet>, uint32_t> m_unicastForwardTrace;

  /// Trace of locally delivered packets

  TracedCallback<const Ipv4Header &, Ptr<const Packet>, uint32_t> m_localDeliverTrace;

  // The following two traces pass a packet with an IP header

  /// Trace of transmitted packets

  TracedCallback<Ptr<const Packet>, Ptr<Ipv4>,  uint32_t> m_txTrace;

  /// Trace of received packets

  TracedCallback<Ptr<const Packet>, Ptr<Ipv4>, uint32_t> m_rxTrace;

  // <ip-header, payload, reason, ifindex> (ifindex not valid if reason is DROP_NO_ROUTE)

  /// Trace of dropped packets

  TracedCallback<const Ipv4Header &, Ptr<const Packet>, DropReason, Ptr<Ipv4>, uint32_t> m_dropTrace;

  Ptr<Ipv4RoutingProtocol> m_routingProtocol; //!< Routing protocol associated with the stack

  SocketList m_sockets; //!< List of IPv4 raw sockets.

  /**

   * \class Fragments

   * \brief A Set of Fragment belonging to the same packet (src, dst, identification and proto)

   */

  class Fragments : public SimpleRefCount<Fragments>

  {

public:

    /**

     * \brief Constructor.

     */

    Fragments ();

    /**

     * \brief Destructor.

     */

    ~Fragments ();

    /**

     * \brief Add a fragment.

     * \param fragment the fragment

     * \param fragmentOffset the offset of the fragment

     * \param moreFragment the bit "More Fragment"

     */

    void AddFragment (Ptr<Packet> fragment, uint16_t fragmentOffset, bool moreFragment);

    /**

     * \brief If all fragments have been added.

     * \returns true if the packet is entire

     */

    bool IsEntire () const;

    /**

     * \brief Get the entire packet.

     * \return the entire packet

     */

    Ptr<Packet> GetPacket () const;

    /**

     * \brief Get the complete part of the packet.

     * \return the part we have comeplete

     */

    Ptr<Packet> GetPartialPacket () const;

private:

    /**

     * \brief True if other fragments will be sent.

     */

    bool m_moreFragment;

    /**

     * \brief The current fragments.

     */

    std::list<std::pair<Ptr<Packet>, uint16_t> > m_fragments;