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

/*

 * Copyright (c) 2005,2006 INRIA

 *

 * 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: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>

 */

/*

 * Documentation kindly pointed out by Tom Henderson:

 * http://wiki.ethereal.com/Development/LibpcapFileFormat

 */

#include <fstream>

#include "ns3/log.h"

#include "ns3/assert.h"

#include "ns3/abort.h"

#include "ns3/simulator.h"

#include "pcap-writer.h"

#include "packet.h"

NS_LOG_COMPONENT_DEFINE ("PcapWriter");

namespace ns3 {

enum {

  PCAP_ETHERNET = 1,

  PCAP_PPP      = 9,

  PCAP_RAW_IP   = 101,

  PCAP_80211    = 105,

  PCAP_80211_PRISM = 119,

  PCAP_80211_RADIOTAP  = 127,

};

PcapWriter::PcapWriter ()

{

  NS_LOG_FUNCTION (this);

  NS_LOG_LOGIC ("m_writer = 0");

  m_writer = 0;

}

PcapWriter::~PcapWriter ()

{

  NS_LOG_FUNCTION (this);

  if (m_writer != 0)

    {

      NS_LOG_LOGIC ("m_writer nonzero " << m_writer);

      if (m_writer->is_open ())

        {

          NS_LOG_LOGIC ("m_writer open.  Closing " << m_writer);

          m_writer->close ();

        }

      NS_LOG_LOGIC ("Deleting writer " << m_writer);

      delete m_writer;

      NS_LOG_LOGIC ("m_writer = 0");

      m_writer = 0;

    }

  else

    {

      NS_LOG_LOGIC ("m_writer == 0");

    }

}

void

PcapWriter::Open (std::string const &name)

{

  NS_LOG_FUNCTION (this << name);

  NS_ABORT_MSG_UNLESS (m_writer == 0, "PcapWriter::Open(): m_writer already allocated (std::ofstream leak detected)");

  m_writer = new std::ofstream ();

  NS_ABORT_MSG_UNLESS (m_writer, "PcapWriter::Open(): Cannot allocate m_writer");

  NS_LOG_LOGIC ("Created writer " << m_writer);

  m_writer->open (name.c_str (), std::ios_base::binary | std::ios_base::out);

  NS_ABORT_MSG_IF (m_writer->fail (), "PcapWriter::Open(): m_writer->open(" << name.c_str () << ") failed");

  NS_ASSERT_MSG (m_writer->is_open (), "PcapWriter::Open(): m_writer not open");

  NS_LOG_LOGIC ("Writer opened successfully");

}

void 

PcapWriter::WriteEthernetHeader (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  WriteHeader (PCAP_ETHERNET);

}

void 

PcapWriter::WriteIpHeader (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  WriteHeader (PCAP_RAW_IP);

}

void

PcapWriter::WriteWifiHeader (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  WriteHeader (PCAP_80211);

}

void

PcapWriter::WriteWifiRadiotapHeader (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  WriteHeader (PCAP_80211_RADIOTAP);

}

void

PcapWriter::WriteWifiPrismHeader (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  WriteHeader (PCAP_80211_PRISM);

}

void 

PcapWriter::WritePppHeader (void)

{

  NS_LOG_FUNCTION_NOARGS ();

  WriteHeader (PCAP_PPP);

}

void 

PcapWriter::WriteHeader (uint32_t network)

{

  NS_LOG_FUNCTION (this << network);

  Write32 (0xa1b2c3d4);

  Write16 (2);

  Write16 (4);

  Write32 (0);

  Write32 (0);

  Write32 (0xffff);

  Write32 (network);

  m_pcapMode = network;

}

void 

PcapWriter::WritePacket (Ptr<const Packet> packet)

{

  if (m_writer != 0) 

    {

      uint64_t current = Simulator::Now ().GetMicroSeconds ();

      uint64_t s = current / 1000000;

      uint64_t us = current % 1000000;

      Write32 (s & 0xffffffff);

      Write32 (us & 0xffffffff);

    }

}

void PcapWriter::WriteWifiMonitorPacket(Ptr<const Packet> packet, uint16_t channelFreqMhz, 

                                        uint32_t rate, bool isShortPreamble, bool isTx, 

                                        double signalDbm, double noiseDbm)

{  

  NS_LOG_FUNCTION (this << packet->GetSize() << channelFreqMhz << rate << isShortPreamble << isTx << signalDbm << noiseDbm);

  if (m_writer == 0) 

    {

      return;

    }

  if (m_pcapMode == PCAP_80211)

    {

      WritePacket (packet);    

      return;

    }

  /* the following is common between PRISM and RADIOTAP */

  uint64_t current = Simulator::Now ().GetMicroSeconds ();

  uint64_t s = current / 1000000;

  uint64_t us = current % 1000000;

  Write32 (s & 0xffffffff);

  Write32 (us & 0xffffffff);

  // MAC timestamp. Actually according to radiotap specifications

  // (http://www.radiotap.org/defined-fields/TSFT) this should be

  // the time "when the first bit of the MPDU arrived at the

  // MAC". This is not exactly what we're doing here, but to handle

  // this properly we would need to first of all investigate how

  // real devices (e.g. madwifi) handle this case, especially for TX

  // packets (radiotap specs says TSFT is not used for TX packets,

  // but madwifi actually uses it).

  if (m_pcapMode == PCAP_80211_PRISM)

    {

#define PRISM_MSG_CODE		 0x00000044

#define PRISM_MSG_LENGTH         144

#define PRISM_DID_HOSTTIME	 0x00010044

#define PRISM_DID_MACTIME	 0x00020044

#define PRISM_DID_CHANNEL	 0x00030044

#define PRISM_DID_RSSI	         0x00040044

#define PRISM_DID_SQ		 0x00050044

#define PRISM_DID_SIGNAL	 0x00060044

#define PRISM_DID_NOISE	         0x00070044

#define PRISM_DID_RATE	         0x00080044

#define PRISM_DID_ISTX	         0x00090044

#define PRISM_DID_FRMLEN	 0x000A0044

#define PRISM_STATUS_PRESENT    0

#define PRISM_STATUS_ABSENT     1

#define PRISM_ITEM_LENGTH       4

      Write32(PRISM_MSG_CODE);

      Write32(PRISM_MSG_LENGTH);

      WriteData((const uint8_t *)"unknown wifi device!!!!!!!!", 16);

      Write32(PRISM_DID_HOSTTIME);

      Write16(PRISM_STATUS_PRESENT);

      Write16(PRISM_ITEM_LENGTH); 

      // madwifi reports hosttime in jiffies. 

      // We calculate jiffies assuming HZ = 10

      Write32((uint32_t) (Now ().GetMilliSeconds () / 10 ) ); 

      Write32(PRISM_DID_MACTIME);

      Write16(PRISM_STATUS_PRESENT);

      Write16(PRISM_ITEM_LENGTH); 

      // This looses precision, which is a well-known issue of the prism

      // header format.

      Write32((uint32_t) tsft);

      Write32(PRISM_DID_CHANNEL);

      Write16(PRISM_STATUS_PRESENT);

      Write16(PRISM_ITEM_LENGTH); 

      // convert from frequency to channel number. This conversion is

      // correct only for IEEE 802.11b/g channels 1-13.

      Write32((2437 - 2407) / 5);

      Write32(PRISM_DID_RSSI);

      Write16(PRISM_STATUS_PRESENT);

      Write16(PRISM_ITEM_LENGTH); 

      // madwifi here reports a value which is said to be "the value in

      // dBm above noise". Apart from the fact that this is incorrect

      // (if it is relative to a value in dBm, then it must be in dB,

      // not in dBm again), this means that in fact it is not a RSSI

      // (which stands for Received Signal Strength Indicator) but it is

      // rather a Signal to Noise Ratio (SNR), of course in dB.

      // Anyway, in the end we calculate the value exactly as madwifi does.

      Write32((uint32_t)round(signalDbm - noiseDbm));

      // SQ field not used. I would expect a PRISM_STATUS_ABSENT to be

      // needed here, but if you look at the prism header that madwifi

      // produces you'll just see that the whole field structure is

      // zeroed. 

      Write32(0);

      Write16(0);

      Write16(0); 

      Write32(0);

      Write32(PRISM_DID_SIGNAL);

      Write16(PRISM_STATUS_PRESENT);

      Write16(PRISM_ITEM_LENGTH); 

      Write32((uint32_t)round(signalDbm));

      Write32(PRISM_DID_NOISE);

      Write16(PRISM_STATUS_PRESENT);

      Write16(PRISM_ITEM_LENGTH); 

      Write32((uint32_t)round(noiseDbm));

      Write32(PRISM_DID_RATE);    

      Write16(PRISM_STATUS_PRESENT);

      Write16(PRISM_ITEM_LENGTH); 

      Write32(rate);

      Write32(PRISM_DID_ISTX);

      Write16(PRISM_STATUS_PRESENT);

      Write16(PRISM_ITEM_LENGTH); 

      Write32(isTx ? 1 : 0);

      Write32(PRISM_DID_FRMLEN);

      Write16(PRISM_STATUS_ABSENT);

      Write16(PRISM_ITEM_LENGTH); 

      Write32(packet->GetSize ());    

    } // PCAP_80211_PRISM

  else if (m_pcapMode == PCAP_80211_RADIOTAP)

    {      

      NS_LOG_LOGIC("writing radiotap packet");

#define	RADIOTAP_TSFT               0x00000001

#define	RADIOTAP_FLAGS              0x00000002

#define	RADIOTAP_RATE               0x00000004

#define RADIOTAP_CHANNEL            0x00000008

#define	RADIOTAP_FHSS               0x00000010

#define RADIOTAP_DBM_ANTSIGNAL      0x00000020

#define RADIOTAP_DBM_ANTNOISE       0x00000040

#define RADIOTAP_LOCK_QUALITY       0x00000080

#define RADIOTAP_TX_ATTENUATION     0x00000100    

#define RADIOTAP_DB_TX_ATTENUATION  0x00000200

#define RADIOTAP_DBM_TX_POWER       0x00000200

#define RADIOTAP_ANTENNA            0x00000400

#define RADIOTAP_DB_ANTSIGNAL       0x00000800

#define RADIOTAP_DB_ANTNOISE        0x00001000

#define RADIOTAP_EXT                0x10000000

#define	RADIOTAP_FLAG_NONE	   0x00	

#define	RADIOTAP_FLAG_CFP	   0x01	

#define	RADIOTAP_FLAG_SHORTPRE	   0x02	

#define	RADIOTAP_FLAG_WEP	   0x04	

#define	RADIOTAP_FLAG_FRAG	   0x08	

#define	RADIOTAP_FLAG_FCS	   0x10	

#define	RADIOTAP_FLAG_DATAPAD	   0x20	

#define	RADIOTAP_FLAG_BADFCS	   0x40	

#define	RADIOTAP_CHANNEL_TURBO	  0x0010

#define	RADIOTAP_CHANNEL_CCK	  0x0020

#define	RADIOTAP_CHANNEL_OFDM	  0x0040

#define	RADIOTAP_CHANNEL_2GHZ	  0x0080

#define	RADIOTAP_CHANNEL_5GHZ	  0x0100

#define	RADIOTAP_CHANNEL_PASSIVE  0x0200

#define	RADIOTAP_CHANNEL_DYN	  0x0400

#define	RADIOTAP_CHANNEL_GFSK	  0x0800

#define RADIOTAP_RX_PRESENT (RADIOTAP_TSFT | RADIOTAP_FLAGS | RADIOTAP_RATE | RADIOTAP_CHANNEL | RADIOTAP_DBM_ANTSIGNAL | RADIOTAP_DBM_ANTNOISE)

#define RADIOTAP_RX_LENGTH (8+8+1+1+2+2+1+1)

#define RADIOTAP_TX_PRESENT (RADIOTAP_TSFT | RADIOTAP_FLAGS  | RADIOTAP_RATE | RADIOTAP_CHANNEL)

#define RADIOTAP_TX_LENGTH (8+8+1+1+2+2)

      if (isTx)

        {

        }

      else

        {

        }

      Write8(0); // radiotap version

      Write8(0); // padding

      if (isTx)

        {

          Write16(RADIOTAP_TX_LENGTH); 

          Write32(RADIOTAP_TX_PRESENT); 

        }

      else

        {

          Write16(RADIOTAP_RX_LENGTH); 

          Write32(RADIOTAP_RX_PRESENT); 

        }

      Write64(tsft); 

      uint8_t flags = RADIOTAP_FLAG_NONE;

      if (isShortPreamble)

        {

          flags |= RADIOTAP_FLAG_SHORTPRE; 

        }

      Write8(flags);

      Write8(rate); 

      Write16((uint16_t) 2437); 

      // we might want to make this setting depend on the WifiMode and

      // on the ChannelFrequency at some time in the future. But for now

      // I think a fixed setting is more than enough for most purposes.

      Write16(RADIOTAP_CHANNEL_OFDM | RADIOTAP_CHANNEL_2GHZ); 

      if (!isTx)

        {

          Write8 (RoundToInt8 (signalDbm)); 

          Write8 (RoundToInt8 (noiseDbm)); 

        }

    } // PCAP_80211_RADIOTAP

  else

    {

      NS_LOG_ERROR("unknown PCAP mode");      

      return;

    }    

  // finally, write rest of packet

}

int8_t 

PcapWriter::RoundToInt8 (double value)

{

  if (value < -128)

    {

      return -128;

    }

  if (value > 127)

    {

      return 127;

    }

  return ((int8_t) round(value));

}