#include "NullLoopbackLayer.h"

#include "EthLayer.h"

#include "IPv4Layer.h"

#include "IPv6Layer.h"

#include "PayloadLayer.h"

namespace pcpp

{

#define BSWAP16(x) (((x) >> 8) | ((x) << 8))

#define BSWAP32(x) (((x) >> 24) | (((x) & 0x00FF'0000) >> 8) | (((x) & 0x0000'FF00) << 8) | ((x) << 24))

#define IEEE_802_3_MAX_LEN 0x5dc

  NullLoopbackLayer::NullLoopbackLayer(uint32_t family)

  {

    const size_t dataLen = sizeof(uint32_t);

    m_DataLen = dataLen;

    m_Data = new uint8_t[dataLen];

    memset(m_Data, 0, dataLen);

    m_Protocol = NULL_LOOPBACK;

    setFamily(family);

  }

  uint32_t NullLoopbackLayer::getFamily() const

  {

    uint32_t family = *(reinterpret_cast<uint32_t*>(m_Data));

    if ((family & 0xFFFF'0000) != 0)

    {

      if ((family & 0xFF00'0000) == 0 && (family & 0x00FF'0000) < 0x0006'0000)

      {

        family >>= 16;

      }

      else

      {

        family = BSWAP32(family);

      }

    }

    else if ((family & 0x0000'00FF) == 0 && (family & 0x0000'FF00) < 0x0000'0600)

    {

      family = BSWAP16(family & 0xFFFF);

    }

    return family;

  }

  void NullLoopbackLayer::setFamily(uint32_t family)

  {

    *m_Data = family;

  }

  void NullLoopbackLayer::parseNextLayer()

  {

    uint8_t* payload = m_Data + sizeof(uint32_t);

    size_t payloadLen = m_DataLen - sizeof(uint32_t);

    uint32_t family = getFamily();

    if (family > IEEE_802_3_MAX_LEN)

    {

      uint16_t ethType = static_cast<uint16_t>(family);

      switch (ethType)

      {

      case PCPP_ETHERTYPE_IP:

        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));

        return;

      case PCPP_ETHERTYPE_IPV6:

        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));

        return;

      default:

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

        return;

      }

    }

    switch (family)

    {

    case PCPP_BSD_AF_INET:

      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 PCPP_BSD_AF_INET6_BSD:

    case PCPP_BSD_AF_INET6_FREEBSD:

    case PCPP_BSD_AF_INET6_DARWIN:

      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);

    }

  }

  std::string NullLoopbackLayer::toString() const

  {

    return "Null/Loopback";

  }

}  // namespace pcpp