#include "NullLoopbackLayer.h"
#include "EthLayer.h"
#include "IPv4Layer.h"
#include "IPv6Layer.h"
#include "PayloadLayer.h"
#include <string.h>

namespace pcpp
{

#define BSWAP16(x) (((x) >> 8) | ((x) << 8))
#define BSWAP32(x) (((x) >> 24) | (((x) & 0x00FF0000) >> 8) \
                  | (((x) & 0x0000FF00) << 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 = *(uint32_t*)m_Data;
	if ((family & 0xFFFF0000) != 0)
	{
		if ((family & 0xFF000000) == 0 && (family & 0x00FF0000) < 0x00060000)
		{
			family >>= 16;
		}
		else
		{
			family = BSWAP32(family);
		}
	}
	else if ((family & 0x000000FF) == 0 && (family & 0x0000FF00) < 0x00000600)
	{
		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 = (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";
}

}