#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))

  constexpr uint32_t Ieee8023MaxLength = 0x5dc;

  NullLoopbackLayer::NullLoopbackLayer(uint32_t family)

  {

    allocData(sizeof(uint32_t));

    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 > Ieee8023MaxLength)

    {

      uint16_t ethType = static_cast<uint16_t>(family);

      switch (ethType)

      {

      case PCPP_ETHERTYPE_IP:

      {

        tryConstructNextLayerWithFallback<IPv4Layer, PayloadLayer>(payload, payloadLen);

        return;

      }

      case PCPP_ETHERTYPE_IPV6:

      {

        tryConstructNextLayerWithFallback<IPv6Layer, PayloadLayer>(payload, payloadLen);

        return;

      }

      default:

      {

        constructNextLayer<PayloadLayer>(payload, payloadLen);

        return;

      }

      }

    }

    switch (family)

    {

    case PCPP_BSD_AF_INET:

    {

      tryConstructNextLayerWithFallback<IPv4Layer, PayloadLayer>(payload, payloadLen);

      break;

    }

    case PCPP_BSD_AF_INET6_BSD:

    case PCPP_BSD_AF_INET6_FREEBSD:

    case PCPP_BSD_AF_INET6_DARWIN:

    {

      tryConstructNextLayerWithFallback<IPv6Layer, PayloadLayer>(payload, payloadLen);

      break;

    }

    default:

    {

      constructNextLayer<PayloadLayer>(payload, payloadLen);

      break;

    }

    }

  }

  std::string NullLoopbackLayer::toString() const

  {

    return "Null/Loopback";

  }

  const FieldDescriptor NullLoopbackLayer::SerializedFields::Family{ Layer::SerializedFields::MaxID + 1, "family" };

  void NullLoopbackLayer::serializeLayer(ObjectScope& serializer) const

  {

    serializer.writeField(SerializedFields::Family, getFamily());

  }

}  // namespace pcpp