#define LOG_MODULE PacketLogModuleIcmpV6Layer

#include "IcmpV6Layer.h"
#include "EndianPortable.h"
#include "IPv4Layer.h"
#include "IPv6Layer.h"
#include "NdpLayer.h"
#include "PacketUtils.h"
#include "PayloadLayer.h"
#include <memory>
#include <sstream>

// IcmpV6Layer

namespace pcpp
{

Layer* IcmpV6Layer::parseIcmpV6Layer(uint8_t *data, size_t dataLen, Layer* prevLayer, Packet* packet)
{
	if (dataLen < sizeof(icmpv6hdr))
		return new PayloadLayer(data, dataLen, prevLayer, packet);

	icmpv6hdr *hdr = (icmpv6hdr *)data;
	ICMPv6MessageType messageType = static_cast<ICMPv6MessageType>(hdr->type);

	switch (messageType)
	{
	case ICMPv6MessageType::ICMPv6_ECHO_REQUEST:
	case ICMPv6MessageType::ICMPv6_ECHO_REPLY:
		return new ICMPv6EchoLayer(data, dataLen, prevLayer, packet);
	case ICMPv6MessageType::ICMPv6_NEIGHBOR_SOLICITATION:
		return new NDPNeighborSolicitationLayer(data, dataLen, prevLayer, packet);
	case ICMPv6MessageType::ICMPv6_NEIGHBOR_ADVERTISEMENT:
		return new NDPNeighborAdvertisementLayer(data, dataLen, prevLayer, packet);
	case ICMPv6MessageType::ICMPv6_UNKNOWN_MESSAGE:
		return new PayloadLayer(data, dataLen, prevLayer, packet);
	default:
		return new IcmpV6Layer(data, dataLen, prevLayer, packet);
	}
}

IcmpV6Layer::IcmpV6Layer(ICMPv6MessageType msgType, uint8_t code, const uint8_t *data, size_t dataLen)
{
	m_DataLen = sizeof(icmpv6hdr) + dataLen;
	m_Data = new uint8_t[m_DataLen];
	memset(m_Data, 0, m_DataLen);
	m_Protocol = ICMPv6;

	icmpv6hdr *hdr = (icmpv6hdr *)m_Data;
	hdr->type = static_cast<uint8_t>(msgType);
	hdr->code = code;

	if (data != nullptr && dataLen > 0)
		memcpy(m_Data + sizeof(icmpv6hdr), data, dataLen);
}

ICMPv6MessageType IcmpV6Layer::getMessageType() const
{
	return static_cast<ICMPv6MessageType>(getIcmpv6Header()->type);
}

uint8_t IcmpV6Layer::getCode() const
{
	return getIcmpv6Header()->code;
}

uint16_t IcmpV6Layer::getChecksum() const
{
	return be16toh(getIcmpv6Header()->checksum);
}

void IcmpV6Layer::computeCalculateFields()
{
	calculateChecksum();
}

void IcmpV6Layer::calculateChecksum()
{
	/* Pseudo header of 40 bytes which is composed as follows(in order):
	- 16 bytes for the source address
	- 16 bytes for the destination address
	- 4 bytes big endian payload length(the same value as in the IPv6 header)
	- 3 bytes zero + 1 byte nextheader( 58 decimal) big endian
	*/

	getIcmpv6Header()->checksum = 0;

	if (m_PrevLayer != nullptr)
	{
		ScalarBuffer<uint16_t> vec[2];

		vec[0].buffer = (uint16_t *)m_Data;
		vec[0].len = m_DataLen;

		const unsigned int pseudoHeaderLen = 40;
		const unsigned int bigEndianLen = htobe32(m_DataLen);
		const unsigned int bigEndianNextHeader = htobe32(PACKETPP_IPPROTO_ICMPV6);

		uint16_t pseudoHeader[pseudoHeaderLen / 2];
		((IPv6Layer *)m_PrevLayer)->getSrcIPv6Address().copyTo((uint8_t *)pseudoHeader);
		((IPv6Layer *)m_PrevLayer)->getDstIPv6Address().copyTo((uint8_t *)(pseudoHeader + 8));
		memcpy(&pseudoHeader[16], &bigEndianLen, sizeof(uint32_t));
		memcpy(&pseudoHeader[18], &bigEndianNextHeader, sizeof(uint32_t));
		vec[1].buffer = pseudoHeader;
		vec[1].len = pseudoHeaderLen;

		/* Calculate and write checksum */
		getIcmpv6Header()->checksum = htobe16(computeChecksum(vec, 2));
	}
}

std::string IcmpV6Layer::toString() const
{
	std::ostringstream typeStream;
	typeStream << (int)getMessageType();
	return "ICMPv6 Layer, Message type: " + typeStream.str();
}

//
// ICMPv6EchoLayer
//

ICMPv6EchoLayer::ICMPv6EchoLayer(ICMPv6EchoType echoType, uint16_t id, uint16_t sequence, const uint8_t *data, size_t dataLen)
{
	m_DataLen = sizeof(icmpv6_echo_hdr) + dataLen;
	m_Data = new uint8_t[m_DataLen];
	memset(m_Data, 0, m_DataLen);
	m_Protocol = ICMPv6;

	icmpv6_echo_hdr *header = getEchoHeader();

	switch (echoType)
	{
	case REPLY:
		header->type = static_cast<uint8_t>(ICMPv6MessageType::ICMPv6_ECHO_REPLY);
		break;
	case REQUEST:
	default:
		header->type = static_cast<uint8_t>(ICMPv6MessageType::ICMPv6_ECHO_REQUEST);
		break;
	}

	header->code = 0;
	header->checksum = 0;
	header->id = htobe16(id);
	header->sequence = htobe16(sequence);

	if (data != nullptr && dataLen > 0)
		memcpy(getEchoDataPtr(), data, dataLen);
}

uint16_t ICMPv6EchoLayer::getIdentifier() const
{
	return be16toh(getEchoHeader()->id);
}

uint16_t ICMPv6EchoLayer::getSequenceNr() const
{
	return be16toh(getEchoHeader()->sequence);
}

std::string ICMPv6EchoLayer::toString() const
{
	std::ostringstream typeStream;
	typeStream << (int)getMessageType();
	return "ICMPv6 Layer, Echo Request/Reply Message (type: " + typeStream.str() + ")";
}

} // namespace pcpp