/*

 * Copyright (c) 2009 CTTC

 *

 * 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, Include., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *

 * Author: Nicola Baldo <nbaldo@cttc.es>

 */

#ifndef RADIOTAP_HEADER_H

#define RADIOTAP_HEADER_H

#include <ns3/header.h> 

namespace ns3 {

/**

 * @brief Radiotap header implementation

 *

 * Radiotap is a de facto standard for 802.11 frame injection and reception. 

 * The radiotap header format is a mechanism to supply additional information 

 * about frames, from the driver to userspace applications such as libpcap, and 

 * from a userspace application to the driver for transmission. 

 *

 * @warning the radiotap header specification says that the fields included in

 * the header should be aligned to their natural ize (e.g., 16-bit fields 

 * aligned to 16-bit boundaries, 32-bit fields aligned to 32-bit boundaries, 

 * and so on.  This implementation does not enforce this.  However, the radiotap

 * specification enforces an order in which fields have to appear (if they 

 * appear), and this ordering is such that, provided you don't leave gaps, all

 * fields will end up aligned without the need of inserting padding space.  By 

 * the term "gap" I mean not using a field which would appear between two used 

 * fields.  Moral: don't leave gaps, or if you do be careful about how you

 * do it.

 */

class RadiotapHeader : public Header

{

public:

  RadiotapHeader();

  static TypeId GetTypeId (void);

  virtual TypeId GetInstanceTypeId (void) const;

  /**

   * This method is used by Packet::AddHeader to store the header into the byte

   * buffer of a packet.  This method returns the number of bytes which are 

   * needed to store the header data during a Serialize.

   *

   * @returns The expected size of the header.

   */

  virtual uint32_t GetSerializedSize (void) const;

  /**

   * This method is used by Packet::AddHeader to store the header into the byte

   * buffer of a packet.  The data written is expected to match bit-for-bit the 

   * representation of this header in a real network.

   *

   * @param start An iterator which points to where the header should

   *              be written.

   */

  virtual void Serialize (Buffer::Iterator start) const;

  /**

   * This method is used by Packet::RemoveHeader to re-create a header from the 

   * byte buffer of a packet.  The data read is expected to match bit-for-bit 

   * the representation of this header in real networks.

   *

   * @param start An iterator which points to where the header should

   *              written.

   * @returns The number of bytes read.

   */

  virtual uint32_t Deserialize (Buffer::Iterator start);

  /**

   * This method is used by Packet::Print to print the content of the header as 

   * ascii data to a C++ output stream.  Although the header is free to format 

   * its output as it wishes, it is recommended to follow a few rules to integrate

   * with the packet pretty printer: start with flags, small field 

   * values located between a pair of parens. Values should be separated 

   * by whitespace. Follow the parens with the important fields, 

   * separated by whitespace.

   *

   * eg: (field1 val1 field2 val2 field3 val3) field4 val4 field5 val5

   *

   * @param os The output stream

   */

  virtual void Print (std::ostream &os) const;

  /**

   * @brief Set the Time Synchronization Function Timer (TSFT) value.  Valid for

   * received frames only. 

   *

   * @param tsft Value in microseconds of the MAC's 64-bit 802.11 Time 

   *             Synchronization Function timer when the first bit of the MPDU

   *             arrived at the MAC.

   */

  void SetTsft (uint64_t tsft);

  /**

   * @brief Get the Time Synchronization Function Timer (TSFT) value.  Valid for

   * received frames only. 

   *

   * @returns The value in microseconds of the MAC's 64-bit 802.11 Time 

   *          Synchronization Function timer when the first bit of the MPDU

   *          arrived at the MAC.

   */

  uint64_t GetTsft (void) const;

  enum {

    FRAME_FLAG_NONE           = 0x00, /**< No flags set */

    FRAME_FLAG_CFP            = 0x01, /**< Frame sent/received during CFP */

    FRAME_FLAG_SHORT_PREAMBLE = 0x02, /**< Frame sent/received with short preamble */

    FRAME_FLAG_WEP            = 0x04, /**< Frame sent/received with WEP encryption */

    FRAME_FLAG_FRAGMENTED     = 0x08, /**< Frame sent/received with fragmentation */

    FRAME_FLAG_FCS_INCLUDED   = 0x10, /**< Frame includes FCS */

    FRAME_FLAG_DATA_PADDING   = 0x20, /**< Frame has padding between 802.11 header and payload (to 32-bit boundary) */

    FRAME_FLAG_BAD_FCS        = 0x40, /**< Frame failed FCS check */

    FRAME_FLAG_SHORT_GUARD    = 0x80  /**< Frame used short guard interval (HT) */

  };

  /**

   * @brief Set the frame flags of the transmitted or received frame.

   * @param flags flags to set.

   */

  void SetFrameFlags (uint8_t flags);

  /**

   * @brief Get the frame flags of the transmitted or received frame.

   * @returns The frame flags.

   * @see FrameFlags.

   */

  uint8_t GetFrameFlags (void) const;

  /**

   * @brief Set the transmit/receive channel frequency in units of megahertz

   * @param rate the transmit/receive channel frequency in units of megahertz.

   */

  void SetRate (uint8_t rate);

  /**

   * @brief Get the transmit/receive channel frequency in units of megahertz.

   * @returns The transmit/receive channel frequency in units of megahertz.

   */

  uint8_t GetRate (void) const;

  enum {

    CHANNEL_FLAG_NONE          = 0x0000, /**< No flags set */

    CHANNEL_FLAG_TURBO         = 0x0010, /**< Turbo Channel */

    CHANNEL_FLAG_CCK           = 0x0020, /**< CCK channel */

    CHANNEL_FLAG_OFDM          = 0x0040, /**< OFDM channel */

    CHANNEL_FLAG_SPECTRUM_2GHZ = 0x0080, /**< 2 GHz spectrum channel */

    CHANNEL_FLAG_SPECTRUM_5GHZ = 0x0100, /**< 5 GHz spectrum channel */

    CHANNEL_FLAG_PASSIVE       = 0x0200, /**< Only passive scan allowed */

    CHANNEL_FLAG_DYNAMIC       = 0x0400, /**< Dynamic CCK-OFDM channel */

    CHANNEL_FLAG_GFSK          = 0x0800  /**< GFSK channel (FHSS PHY) */

  };

  /**

   * @brief Set the transmit/receive channel frequency and flags

   * @param frequency The transmit/receive data rate in units of 500 kbps.

   * @param flags The flags to set.

   * @see ChannelFlags

   */

  void SetChannelFrequencyAndFlags (uint16_t frequency, uint16_t flags);

  /**

   * @brief Get the transmit/receive data rate in units of 500 kbps.

   * @returns The transmit/receive data rate in units of 500 kbps.

   */

  uint16_t GetChannelFrequency (void) const;

  /**

   * @brief Get the channel flags of the transmitted or received frame.

   * @returns The frame flags.

   * @see ChannelFlags.

   */

  uint16_t GetChannelFlags (void) const;

  /**

   * @brief Set the RF signal power at the antenna as a decibel difference

   * from an arbitrary, fixed reference. 

   *

   * @param signal The RF signal power at the antenna as a decibel difference

   *               from an arbitrary, fixed reference;

   */

  void SetAntennaSignalPower (double signal);

  /**

   * @brief Get the RF signal power at the antenna as a decibel difference

   * from an arbitrary, fixed reference. 

   *

   * @returns The RF signal power at the antenna as a decibel difference

   *          from an arbitrary, fixed reference. 

   */

  uint8_t GetAntennaSignalPower (void) const;

  /**

   * @brief Set the RF noise power at the antenna as a decibel difference

   * from an arbitrary, fixed reference. 

   *

   * @param noise The RF noise power at the antenna as a decibel difference

   *              from an arbitrary, fixed reference. 

   */

  void SetAntennaNoisePower (double noise);

  /**

   * @brief Get the RF noise power at the antenna as a decibel difference

   * from an arbitrary, fixed reference. 

   *

   * @returns The RF noise power at the antenna as a decibel difference

   *          from an arbitrary, fixed reference. 

   */

  uint8_t GetAntennaNoisePower (void) const;

private:

  enum {

    RADIOTAP_TSFT              = 0x00000001,

    RADIOTAP_FLAGS             = 0x00000002,

    RADIOTAP_RATE              = 0x00000004,

    RADIOTAP_CHANNEL           = 0x00000008,

    RADIOTAP_FHSS              = 0x00000010,

    RADIOTAP_DBM_ANTSIGNAL     = 0x00000020,

    RADIOTAP_DBM_ANTNOISE      = 0x00000040,

    RADIOTAP_LOCK_QUALITY      = 0x00000080,

    RADIOTAP_TX_ATTENUATION    = 0x00000100,

    RADIOTAP_DB_TX_ATTENUATION = 0x00000200,

    RADIOTAP_DBM_TX_POWER      = 0x00000200,

    RADIOTAP_ANTENNA           = 0x00000400,

    RADIOTAP_DB_ANTSIGNAL      = 0x00000800,

    RADIOTAP_DB_ANTNOISE       = 0x00001000,

    RADIOTAP_EXT               = 0x10000000

  };

  void CheckAddChannelField ();

  uint16_t m_length;

  uint32_t m_present;

  uint64_t m_tsft;

  uint8_t m_flags;

  uint8_t m_rate;

  uint16_t m_channelFreq;

  uint16_t m_channelFlags;

  int8_t m_antennaSignal;

  int8_t m_antennaNoise;

};

} // namespace ns3

#endif /*  RADIOTAP_HEADER_H */