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

/*

 * Copyright (c) 2007 INESC Porto

 *

 * 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: Gustavo J. A. M. Carneiro  <gjc@inescporto.pt>

 */

#include <cmath>

#include "ns3/assert.h"

#include "ns3/log.h"

#include "olsr-header.h"

#define IPV4_ADDRESS_SIZE 4

#define OLSR_MSG_HEADER_SIZE 12

#define OLSR_PKT_HEADER_SIZE 4

namespace ns3 {

namespace olsr {

NS_LOG_COMPONENT_DEFINE ("OlsrHeader");

/// Scaling factor used in RFC 3626.

#define OLSR_C 0.0625

///

/// \brief Converts a decimal number of seconds to the mantissa/exponent format.

///

/// \param seconds decimal number of seconds we want to convert.

/// \return the number of seconds in mantissa/exponent format.

///

uint8_t

SecondsToEmf (double seconds)

{

  int a, b = 0;

  // find the largest integer 'b' such that: T/C >= 2^b

  for (b = 0; (seconds/OLSR_C) >= (1 << b); ++b)

    ;

  NS_ASSERT ((seconds/OLSR_C) < (1 << b));

  b--;

  NS_ASSERT ((seconds/OLSR_C) >= (1 << b));

  // compute the expression 16*(T/(C*(2^b))-1), which may not be a integer

  double tmp = 16*(seconds/(OLSR_C*(1<<b))-1);

  // round it up.  This results in the value for 'a'

  a = (int) std::ceil (tmp);

  // if 'a' is equal to 16: increment 'b' by one, and set 'a' to 0

  if (a == 16)

    {

      b += 1;

      a = 0;

    }

  // now, 'a' and 'b' should be integers between 0 and 15,

  NS_ASSERT (a >= 0 && a < 16);

  NS_ASSERT (b >= 0 && b < 16);

  // the field will be a byte holding the value a*16+b

  return (uint8_t)((a << 4) | b);

}

///

/// \brief Converts a number of seconds in the mantissa/exponent format to a decimal number.

///

/// \param olsr_format number of seconds in mantissa/exponent format.

/// \return the decimal number of seconds.

///

double

EmfToSeconds (uint8_t olsrFormat)

{

  int a = (olsrFormat >> 4);

  int b = (olsrFormat & 0xf);

  // value = C*(1+a/16)*2^b [in seconds]

  return OLSR_C * (1 + a/16.0) * (1 << b);

}

// ---------------- OLSR Packet -------------------------------

NS_OBJECT_ENSURE_REGISTERED (PacketHeader);

PacketHeader::PacketHeader ()

{

}

PacketHeader::~PacketHeader ()

{

}

TypeId

PacketHeader::GetTypeId (void)

{

  static TypeId tid = TypeId ("ns3::olsr::PacketHeader")

    .SetParent<Header> ()

    .AddConstructor<PacketHeader> ()

  ;

  return tid;

}

TypeId

PacketHeader::GetInstanceTypeId (void) const

{

  return GetTypeId ();

}

uint32_t 

PacketHeader::GetSerializedSize (void) const

{

  return OLSR_PKT_HEADER_SIZE;

}

void 

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

{

}

void

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

{

  Buffer::Iterator i = start;

  i.WriteHtonU16 (m_packetLength);

  i.WriteHtonU16 (m_packetSequenceNumber);

}

uint32_t

PacketHeader::Deserialize (Buffer::Iterator start)

{

  Buffer::Iterator i = start;

  m_packetLength  = i.ReadNtohU16 ();

  m_packetSequenceNumber = i.ReadNtohU16 ();

  return GetSerializedSize ();

}

// ---------------- OLSR Message -------------------------------

NS_OBJECT_ENSURE_REGISTERED (MessageHeader);

MessageHeader::MessageHeader ()

  : m_messageType (MessageHeader::MessageType (0))

{

}

MessageHeader::~MessageHeader ()

{

}

TypeId

MessageHeader::GetTypeId (void)

{

  static TypeId tid = TypeId ("ns3::olsr::MessageHeader")

    .SetParent<Header> ()

    .AddConstructor<MessageHeader> ()

  ;

  return tid;

}

TypeId

MessageHeader::GetInstanceTypeId (void) const

{

  return GetTypeId ();

}

uint32_t

MessageHeader::GetSerializedSize (void) const

{

  uint32_t size = OLSR_MSG_HEADER_SIZE;

  switch (m_messageType)

    {

    case MID_MESSAGE:

      size += m_message.mid.GetSerializedSize ();

      break;

    case HELLO_MESSAGE:

      NS_LOG_DEBUG ("Hello Message Size: " << size << " + " << m_message.hello.GetSerializedSize ());

      size += m_message.hello.GetSerializedSize ();

      break;

    case TC_MESSAGE:

      size += m_message.tc.GetSerializedSize ();

      break;

    case HNA_MESSAGE:

      size += m_message.hna.GetSerializedSize ();

      break;

    default:

      NS_ASSERT (false);

    }

  return size;

}

void 

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

{

}

void

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

{

  Buffer::Iterator i = start;

  i.WriteU8 (m_messageType);

  i.WriteU8 (m_vTime);

  i.WriteHtonU16 (GetSerializedSize ());

  i.WriteHtonU32 (m_originatorAddress.Get ());

  i.WriteU8 (m_timeToLive);

  i.WriteU8 (m_hopCount);

  i.WriteHtonU16 (m_messageSequenceNumber);

  switch (m_messageType)

    {

    case MID_MESSAGE:

      m_message.mid.Serialize (i);

      break;

    case HELLO_MESSAGE:

      m_message.hello.Serialize (i);

      break;

    case TC_MESSAGE:

      m_message.tc.Serialize (i);

      break;

    case HNA_MESSAGE:

      m_message.hna.Serialize (i);

      break;

    default:

      NS_ASSERT (false);

    }

}

uint32_t

MessageHeader::Deserialize (Buffer::Iterator start)

{

  uint32_t size;

  Buffer::Iterator i = start;

  m_messageType  = (MessageType) i.ReadU8 ();

  NS_ASSERT (m_messageType >= HELLO_MESSAGE && m_messageType <= HNA_MESSAGE);

  m_vTime  = i.ReadU8 ();

  m_messageSize  = i.ReadNtohU16 ();

  m_originatorAddress = Ipv4Address (i.ReadNtohU32 ());

  m_timeToLive  = i.ReadU8 ();

  m_hopCount  = i.ReadU8 ();

  m_messageSequenceNumber = i.ReadNtohU16 ();

  size = OLSR_MSG_HEADER_SIZE;

  switch (m_messageType)

    {

    case MID_MESSAGE:

      size += m_message.mid.Deserialize (i, m_messageSize - OLSR_MSG_HEADER_SIZE);

      break;

    case HELLO_MESSAGE:

      size += m_message.hello.Deserialize (i, m_messageSize - OLSR_MSG_HEADER_SIZE);

      break;

    case TC_MESSAGE:

      size += m_message.tc.Deserialize (i, m_messageSize - OLSR_MSG_HEADER_SIZE);

      break;

    case HNA_MESSAGE:

      size += m_message.hna.Deserialize (i, m_messageSize - OLSR_MSG_HEADER_SIZE);

      break;

    default:

      NS_ASSERT (false);

    }

  return size;

}

// ---------------- OLSR MID Message -------------------------------

uint32_t 

MessageHeader::Mid::GetSerializedSize (void) const

{

  return this->interfaceAddresses.size () * IPV4_ADDRESS_SIZE;

}

void 

MessageHeader::Mid::Print (std::ostream &os) const

{

}

void

MessageHeader::Mid::Serialize (Buffer::Iterator start) const

{

  Buffer::Iterator i = start;

  for (std::vector<Ipv4Address>::const_iterator iter = this->interfaceAddresses.begin ();

       iter != this->interfaceAddresses.end (); iter++)

    {

      i.WriteHtonU32 (iter->Get ());

    }

}

uint32_t

MessageHeader::Mid::Deserialize (Buffer::Iterator start, uint32_t messageSize)

{

  Buffer::Iterator i = start;

  this->interfaceAddresses.clear ();

  NS_ASSERT (messageSize % IPV4_ADDRESS_SIZE == 0);

  int numAddresses = messageSize / IPV4_ADDRESS_SIZE;

  this->interfaceAddresses.erase (this->interfaceAddresses.begin (),

                                  this->interfaceAddresses.end ());

  for (int n = 0; n < numAddresses; ++n)

    this->interfaceAddresses.push_back (Ipv4Address (i.ReadNtohU32 ()));

  return GetSerializedSize ();

}

// ---------------- OLSR HELLO Message -------------------------------

uint32_t 

MessageHeader::Hello::GetSerializedSize (void) const

{

  uint32_t size = 4;

  for (std::vector<LinkMessage>::const_iterator iter = this->linkMessages.begin ();

       iter != this->linkMessages.end (); iter++)

    {

      const LinkMessage &lm = *iter;

      size += 4;

      size += IPV4_ADDRESS_SIZE * lm.neighborInterfaceAddresses.size ();

    }

  return size;

}

void 

MessageHeader::Hello::Print (std::ostream &os) const

{

}

void

MessageHeader::Hello::Serialize (Buffer::Iterator start) const

{

  Buffer::Iterator i = start;

  i.WriteU16 (0); // Reserved

  i.WriteU8 (this->hTime);

  i.WriteU8 (this->willingness);

  for (std::vector<LinkMessage>::const_iterator iter = this->linkMessages.begin ();

       iter != this->linkMessages.end (); iter++)

    {

      const LinkMessage &lm = *iter;

      i.WriteU8 (lm.linkCode);

      i.WriteU8 (0); // Reserved

      // The size of the link message, counted in bytes and measured

      // from the beginning of the "Link Code" field and until the

      // next "Link Code" field (or - if there are no more link types

      // - the end of the message).

      i.WriteHtonU16 (4 + lm.neighborInterfaceAddresses.size () * IPV4_ADDRESS_SIZE);

      for (std::vector<Ipv4Address>::const_iterator neigh_iter = lm.neighborInterfaceAddresses.begin ();

           neigh_iter != lm.neighborInterfaceAddresses.end (); neigh_iter++)

        {

          i.WriteHtonU32 (neigh_iter->Get ());

        }

    }

}

uint32_t

MessageHeader::Hello::Deserialize (Buffer::Iterator start, uint32_t messageSize)

{

  Buffer::Iterator i = start;

  NS_ASSERT (messageSize >= 4);

  this->linkMessages.clear ();

  uint16_t helloSizeLeft = messageSize;

  i.ReadNtohU16 (); // Reserved

  this->hTime = i.ReadU8 ();

  this->willingness = i.ReadU8 ();

  helloSizeLeft -= 4;

  while (helloSizeLeft)

    {

      LinkMessage lm;

      NS_ASSERT (helloSizeLeft >= 4);

      lm.linkCode = i.ReadU8 ();

      i.ReadU8 (); // Reserved

      uint16_t lmSize = i.ReadNtohU16 ();

      NS_ASSERT ((lmSize - 4) % IPV4_ADDRESS_SIZE == 0);

      for (int n = (lmSize - 4) / IPV4_ADDRESS_SIZE; n; --n)

        {

          lm.neighborInterfaceAddresses.push_back (Ipv4Address (i.ReadNtohU32 ()));

        }

      helloSizeLeft -= lmSize;

      this->linkMessages.push_back (lm);

    }

  return messageSize;

}

// ---------------- OLSR TC Message -------------------------------

uint32_t 

MessageHeader::Tc::GetSerializedSize (void) const

{

  return 4 + this->neighborAddresses.size () * IPV4_ADDRESS_SIZE;

}

void 

MessageHeader::Tc::Print (std::ostream &os) const

{

}

void

MessageHeader::Tc::Serialize (Buffer::Iterator start) const

{

  Buffer::Iterator i = start;

  i.WriteHtonU16 (this->ansn);

  i.WriteHtonU16 (0); // Reserved

  for (std::vector<Ipv4Address>::const_iterator iter = this->neighborAddresses.begin ();

       iter != this->neighborAddresses.end (); iter++)

    {

      i.WriteHtonU32 (iter->Get ());

    }

}

uint32_t

MessageHeader::Tc::Deserialize (Buffer::Iterator start, uint32_t messageSize)

{

  Buffer::Iterator i = start;

  this->neighborAddresses.clear ();

  NS_ASSERT (messageSize >= 4);

  this->ansn = i.ReadNtohU16 ();

  i.ReadNtohU16 (); // Reserved

  NS_ASSERT ((messageSize - 4) % IPV4_ADDRESS_SIZE == 0);

  int numAddresses = (messageSize - 4) / IPV4_ADDRESS_SIZE;

  this->neighborAddresses.clear ();

  for (int n = 0; n < numAddresses; ++n)

    this->neighborAddresses.push_back (Ipv4Address (i.ReadNtohU32 ()));

  return messageSize;

}

// ---------------- OLSR HNA Message -------------------------------

uint32_t 

MessageHeader::Hna::GetSerializedSize (void) const

{

  return 2*this->associations.size () * IPV4_ADDRESS_SIZE;

}

void 

MessageHeader::Hna::Print (std::ostream &os) const

{

}

void

MessageHeader::Hna::Serialize (Buffer::Iterator start) const

{

  Buffer::Iterator i = start;

  for (size_t n = 0; n < this->associations.size (); ++n)

    {

      i.WriteHtonU32 (this->associations[n].address.Get ());

      i.WriteHtonU32 (this->associations[n].mask.Get ());

    }

}

uint32_t

MessageHeader::Hna::Deserialize (Buffer::Iterator start, uint32_t messageSize)

{

  Buffer::Iterator i = start;

  NS_ASSERT (messageSize % (IPV4_ADDRESS_SIZE*2) == 0);

  int numAddresses = messageSize / IPV4_ADDRESS_SIZE / 2;

  this->associations.clear ();

  for (int n = 0; n < numAddresses; ++n)

    {

      Ipv4Address address (i.ReadNtohU32 ());

      Ipv4Mask mask (i.ReadNtohU32 ());