text: /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
  /*
   * Copyright (c) 2010 Hajime Tazaki
   *
   * 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
   *
   * Authors: Hajime Tazaki <tazaki@sfc.wide.ad.jp>
   */
  
  #ifndef IPV4_PACKET_INFO_TAG_H
  #define IPV4_PACKET_INFO_TAG_H
  
  #include "ns3/tag.h"
  #include "ns3/ipv4-address.h"
  
  namespace ns3 {
  
  
  class Node;
  class Packet;
  
  /**
   * \ingroup ipv4
   *
   * \brief This class implements Linux struct pktinfo 
   * in order to deliver ancillary information to the socket interface.
   * This is used with socket option such as IP_PKTINFO, IP_RECVTTL, 
   * IP_RECVTOS. See linux manpage ip(7).
   *
   * This tag in the send direction is presently not enabled but we
   * would accept a patch along those lines in the future.
   */
  class Ipv4PacketInfoTag : public Tag
  {
  public:
    Ipv4PacketInfoTag ();
  
    /**
     * \brief Set the tag's address
     *
     * \param addr the address
     */
    void SetAddress (Ipv4Address addr);
  
    /**
     * \brief Get the tag's address
     *
     * \returns the address
     */
    Ipv4Address GetAddress (void) const;
    /**
     * \brief Set the tag's \a local address
     *
     * This corresponds to "ipi_spec_dst" in struct in_pktinfo.
     * Implemented, but not used in the stack yet
     * \param addr the address
     */
    void SetLocalAddress (Ipv4Address addr);
    /**
     * \brief Get the tag's \a local address
     *
     * This corresponds to "ipi_spec_dst" in struct in_pktinfo.
     * Implemented, but not used in the stack yet
     * \returns the address
     */
    Ipv4Address GetLocalAddress (void) const;
  
    /**
     * \brief Set the tag's receiving interface
     *
     * \param ifindex the interface index
     */
    void SetRecvIf (uint32_t ifindex);
    /**
     * \brief Get the tag's receiving interface
     *
     * \returns the interface index
     */
    uint32_t GetRecvIf (void) const;
  
    /**
     * \brief Set the tag's Time to Live
     * Implemented, but not used in the stack yet
     * \param ttl the TTL
     */
    void SetTtl (uint8_t ttl);
    /**
     * \brief Get the tag's Time to Live
     * Implemented, but not used in the stack yet
     * \returns the TTL
     */
    uint8_t GetTtl (void) const;
  
    /**
     * \brief Get the type ID.
     * \return the object TypeId
     */
    static TypeId GetTypeId (void);
    virtual TypeId GetInstanceTypeId (void) const;
    virtual uint32_t GetSerializedSize (void) const;
    virtual void Serialize (TagBuffer i) const;
    virtual void Deserialize (TagBuffer i);
    virtual void Print (std::ostream &os) const;
  
  private:
    // Linux IP_PKTINFO ip(7) implementation
    // 
    // struct in_pktinfo {
    //   unsigned int   ipi_ifindex;  /* Interface index */
    //   struct in_addr ipi_spec_dst; /* Local address */
    //   struct in_addr ipi_addr;     /* Header Destination
    //                                   address */
    // };
  
    Ipv4Address m_addr;     //!< Header destination address
    Ipv4Address m_spec_dst; //!< Local address
    uint32_t m_ifindex;     //!< interface index
  
    // Used for IP_RECVTTL, though not implemented yet.
    uint8_t m_ttl; //!< Time to Live
  };
  } // namespace ns3
  
  #endif /* IPV4_PACKET_INFO_TAG_H */
  