/* -*- 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 "ns3/assert.h"
#include "ns3/address-utils.h"
#include "arp-header.h"

namespace ns3 {

NS_OBJECT_ENSURE_REGISTERED (ArpHeader);

void 
ArpHeader::SetRequest (Address sourceHardwareAddress,
                       Ipv4Address sourceProtocolAddress,
                       Address destinationHardwareAddress,
                       Ipv4Address destinationProtocolAddress)
{
  m_type = ARP_TYPE_REQUEST;
  m_macSource = sourceHardwareAddress;
  m_macDest = destinationHardwareAddress;
  m_ipv4Source = sourceProtocolAddress;
  m_ipv4Dest = destinationProtocolAddress;
}
void 
ArpHeader::SetReply (Address sourceHardwareAddress,
                     Ipv4Address sourceProtocolAddress,
                     Address destinationHardwareAddress,
                     Ipv4Address destinationProtocolAddress)
{
  m_type = ARP_TYPE_REPLY;
  m_macSource = sourceHardwareAddress;
  m_macDest = destinationHardwareAddress;
  m_ipv4Source = sourceProtocolAddress;
  m_ipv4Dest = destinationProtocolAddress;
}
bool 
ArpHeader::IsRequest (void) const
{
  return (m_type == ARP_TYPE_REQUEST) ? true : false;
}
bool 
ArpHeader::IsReply (void) const
{
  return (m_type == ARP_TYPE_REPLY) ? true : false;
}
Address 
ArpHeader::GetSourceHardwareAddress (void)
{
  return m_macSource;
}
Address 
ArpHeader::GetDestinationHardwareAddress (void)
{
  return m_macDest;
}
Ipv4Address 
ArpHeader::GetSourceIpv4Address (void)
{
  return m_ipv4Source;
}
Ipv4Address 
ArpHeader::GetDestinationIpv4Address (void)
{
  return m_ipv4Dest;
}


TypeId 
ArpHeader::GetTypeId (void)
{
  static TypeId tid = TypeId ("ns3::ArpHeader")
    .SetParent<Header> ()
    .AddConstructor<ArpHeader> ()
  ;
  return tid;
}
TypeId 
ArpHeader::GetInstanceTypeId (void) const
{
  return GetTypeId ();
}
void 
ArpHeader::Print (std::ostream &os) const
{
  if (IsRequest ()) 
    {
      os << "request "
         << "source mac: " << m_macSource << " "
         << "source ipv4: " << m_ipv4Source << " "
         << "dest ipv4: " << m_ipv4Dest
      ;
    } 
  else 
    {
      NS_ASSERT (IsReply ());
      os << "reply " 
         << "source mac: " << m_macSource << " "
         << "source ipv4: " << m_ipv4Source << " "
         << "dest mac: " << m_macDest << " "
         << "dest ipv4: " <<m_ipv4Dest
      ;
    }
}
uint32_t 
ArpHeader::GetSerializedSize (void) const
{
  NS_ASSERT((m_macSource.GetLength () == 6) || (m_macSource.GetLength () == 8));
  NS_ASSERT (m_macSource.GetLength () == m_macDest.GetLength ());

  uint32_t length = 16;   // Length minus two hardware addresses
  length += m_macSource.GetLength () * 2;

  return length;
}

void
ArpHeader::Serialize (Buffer::Iterator start) const
{
  Buffer::Iterator i = start;
  NS_ASSERT (m_macSource.GetLength () == m_macDest.GetLength ());

  /* ethernet */
  i.WriteHtonU16 (0x0001);
  /* ipv4 */
  i.WriteHtonU16 (0x0800);
  i.WriteU8 (m_macSource.GetLength ());
  i.WriteU8 (4);
  i.WriteHtonU16 (m_type);
  WriteTo (i, m_macSource);
  WriteTo (i, m_ipv4Source);
  WriteTo (i, m_macDest);
  WriteTo (i, m_ipv4Dest);
}

uint32_t
ArpHeader::Deserialize (Buffer::Iterator start)
{
  Buffer::Iterator i = start;
  i.Next (2);                                    // Skip HRD
  uint32_t protocolType = i.ReadNtohU16 ();      // Read PRO
  uint32_t hardwareAddressLen = i.ReadU8 ();     // Read HLN
  uint32_t protocolAddressLen = i.ReadU8 ();     // Read PLN

  //
  // It is implicit here that we have a protocol type of 0x800 (IP).
  // It is also implicit here that we are using Ipv4 (PLN == 4).
  // If this isn't the case, we need to return an error since we don't want to 
  // be too fragile if we get connected to real networks.
  //
  if (protocolType != 0x800 || protocolAddressLen != 4)
    {
      return 0;
    }

  m_type = i.ReadNtohU16 ();                     // Read OP
  ReadFrom (i, m_macSource, hardwareAddressLen); // Read SHA (size HLN)
  ReadFrom (i, m_ipv4Source);                    // Read SPA (size PLN == 4)
  ReadFrom (i, m_macDest, hardwareAddressLen);   // Read THA (size HLN)
  ReadFrom (i, m_ipv4Dest);                      // Read TPA (size PLN == 4)
  return GetSerializedSize ();
}

} // namespace ns3