#define LOG_MODULE PacketLogModuleMplsLayer

#include "MplsLayer.h"

#include "IPv4Layer.h"

#include "IPv6Layer.h"

#include "PayloadLayer.h"

#include "Logger.h"

#include <string.h>

#include <sstream>

#include "EndianPortable.h"

namespace pcpp

{

MplsLayer::MplsLayer(uint32_t mplsLabel, uint8_t ttl, uint8_t experimentalUseValue, bool bottomOfStack)

{

  const size_t headerLen = sizeof(mpls_header);

  m_DataLen = headerLen;

  m_Data = new uint8_t[headerLen];

  memset(m_Data, 0, headerLen);

  m_Protocol = MPLS;

  setMplsLabel(mplsLabel);

  setTTL(ttl);

  setExperimentalUseValue(experimentalUseValue);

  setBottomOfStack(bottomOfStack);

}

bool MplsLayer::isBottomOfStack() const

{

  return (getMplsHeader()->misc & 0x01);

}

void MplsLayer::setBottomOfStack(bool val)

{

  if (!val)

    getMplsHeader()->misc &= 0xFE;

  else

    getMplsHeader()->misc |= 0x1;

}

uint8_t MplsLayer::getExperimentalUseValue() const

{

  return ((getMplsHeader()->misc & 0x0E) >> 1);

}

bool MplsLayer::setExperimentalUseValue(uint8_t val)

{

  // exp value is only 3 bits

  if (val > 7)

  {

    PCPP_LOG_ERROR("Set ExperimentalUse value got an illegal value: " << (int)val << ". Value must be lower than 8");

    return false;

  }

  mpls_header* hdr = getMplsHeader();

  // clear the 3 exp bits

  hdr->misc &= 0xF1;

  // move the 3 bits to their place

  val = val << 1;

  hdr->misc |= val;

  return true;

}

uint32_t MplsLayer::getMplsLabel() const

{

  return (htobe16(getMplsHeader()->hiLabel) << 4) | ((getMplsHeader()->misc & 0xF0) >> 4);

}

bool MplsLayer::setMplsLabel(uint32_t label)

{

  if (label > 0xFFFFF)

  {

    PCPP_LOG_ERROR("MPLS label mustn't exceed 20 bits which is the value 0xffff. Got a parameter with the value 0x" << std::hex << label);

    return false;

  }

  mpls_header* hdr = getMplsHeader();

  // clear the 4 label bits in misc field

  hdr->misc &= 0x0F;

  // take the last nibble of the label value and move this nibble to its place in misc

  uint8_t miscVal = (label & 0x0F) << 4;

  // update misc field

  hdr->misc |= miscVal;

  // get rid of the nibble that went to misc

  label = label >> 4;

  // set the high 2 bytes of the label

  hdr->hiLabel = (uint16_t)htobe16(label);

  return true;

}

void MplsLayer::parseNextLayer()

{

  size_t headerLen = getHeaderLen();

  if (m_DataLen < headerLen + 1)

    return;

  uint8_t* payload = m_Data + sizeof(mpls_header);

  size_t payloadLen = m_DataLen - sizeof(mpls_header);

  if (!isBottomOfStack())

  {

    m_NextLayer = new MplsLayer(payload, payloadLen, this, m_Packet);

    return;

  }

  uint8_t nextNibble = (*((uint8_t*)(m_Data + headerLen)) & 0xF0) >> 4;

  switch (nextNibble)

  {

    case 4:

      m_NextLayer = IPv4Layer::isDataValid(payload, payloadLen)

        ? static_cast<Layer*>(new IPv4Layer(payload, payloadLen, this, m_Packet))

        : static_cast<Layer*>(new PayloadLayer(payload, payloadLen, this, m_Packet));

      break;

    case 6:

      m_NextLayer = IPv6Layer::isDataValid(payload, payloadLen)

        ? static_cast<Layer*>(new IPv6Layer(payload, payloadLen, this, m_Packet))

        : static_cast<Layer*>(new PayloadLayer(payload, payloadLen, this, m_Packet));

      break;

    default:

      m_NextLayer = new PayloadLayer(payload, payloadLen, this, m_Packet);

  }

}

void MplsLayer::computeCalculateFields()

{

  Layer* nextLayer = getNextLayer();

  if (nextLayer != NULL)

  {

    setBottomOfStack((nextLayer->getProtocol() != MPLS));

  }

}

std::string MplsLayer::toString() const

{

  std::ostringstream labelStream;

  labelStream << getMplsLabel();

  std::ostringstream expStream;

  expStream << (int)getExperimentalUseValue();

  std::ostringstream ttlStream;

  ttlStream << (int)getTTL();

  std::string bottomOfStack = isBottomOfStack() ? "true" : "false";

  return "MPLS Layer, Label: " + labelStream.str() + ", Exp: " + expStream.str() + ", TTL: " + ttlStream.str() +

      ", Bottom of stack: " + bottomOfStack;

}

} // namespace pcpp