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

/*

 * Copyright (c) 2005 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>

 */

#include "udp-header.h"

#include "ipv4-checksum.h"

namespace ns3 {

NS_OBJECT_ENSURE_REGISTERED (UdpHeader);

bool UdpHeader::m_calcChecksum = false;

/* The magic values below are used only for debugging.

 * They can be used to easily detect memory corruption

 * problems so you can see the patterns in memory.

 */

UdpHeader::UdpHeader ()

  : m_sourcePort (0xfffd),

    m_destinationPort (0xfffd),

    m_payloadSize (0xfffd),

    m_initialChecksum (0)

{}

UdpHeader::~UdpHeader ()

{

  m_sourcePort = 0xfffe;

  m_destinationPort = 0xfffe;

  m_payloadSize = 0xfffe;

}

void 

UdpHeader::EnableChecksums (void)

{

  m_calcChecksum = true;

}

void 

UdpHeader::SetDestinationPort (uint16_t port)

{

  m_destinationPort = port;

}

void 

UdpHeader::SetSourcePort (uint16_t port)

{

  m_sourcePort = port;

}

uint16_t 

UdpHeader::GetSourcePort (void) const

{

  return m_sourcePort;

}

uint16_t 

UdpHeader::GetDestinationPort (void) const

{

  return m_destinationPort;

}

void 

UdpHeader::SetPayloadSize (uint16_t size)

{

  m_payloadSize = size;

}

void 

UdpHeader::InitializeChecksum (Ipv4Address source, 

                              Ipv4Address destination,

                              uint8_t protocol)

{

  uint8_t buf[12];

  source.Serialize (buf);

  destination.Serialize (buf+4);

  buf[8] = 0;

  buf[9] = protocol;

  uint16_t udpLength = m_payloadSize + GetSerializedSize ();

  buf[10] = udpLength >> 8;

  buf[11] = udpLength & 0xff;

  m_initialChecksum = Ipv4ChecksumCalculate (0, buf, 12);

}

TypeId 

UdpHeader::GetTypeId (void)

{

  static TypeId tid = TypeId ("ns3::UdpHeader")

    .SetParent<Header> ()

    .AddConstructor<UdpHeader> ()

    ;

  return tid;

}

TypeId 

UdpHeader::GetInstanceTypeId (void) const

{

  return GetTypeId ();

}

void 

UdpHeader::Print (std::ostream &os) const

{

  os << "length: " << m_payloadSize + GetSerializedSize ()

     << " " 

     << m_sourcePort << " > " << m_destinationPort

    ;

}

uint32_t 

UdpHeader::GetSerializedSize (void) const

{

  return 8;

}

void

UdpHeader::Serialize (Buffer::Iterator start) const

{

  Buffer::Iterator i = start;

  i.WriteHtonU16 (m_sourcePort);

  i.WriteHtonU16 (m_destinationPort);

  i.WriteHtonU16 (m_payloadSize + GetSerializedSize ());

  i.WriteU16 (0);

  if (m_calcChecksum) 

    {

#if 0

      //XXXX

      uint16_t checksum = Ipv4ChecksumCalculate (m_initialChecksum, 

                                                  buffer->PeekData (), 

                                                  GetSerializedSize () + m_payloadSize);

      checksum = Ipv4ChecksumComplete (checksum);

      i = buffer->Begin ();

      i.Next (6);

      i.WriteU16 (checksum);

#endif

    }

}

uint32_t

UdpHeader::Deserialize (Buffer::Iterator start)

{

  Buffer::Iterator i = start;

  m_sourcePort = i.ReadNtohU16 ();

  m_destinationPort = i.ReadNtohU16 ();

  m_payloadSize = i.ReadNtohU16 () - GetSerializedSize ();

  if (m_calcChecksum) 

    {

      // XXX verify checksum.

    }

  return GetSerializedSize ();

}

}; // namespace ns3