Method CalculateChecksum

pcsx2/DEV9/PacketReader/IP/IP_Packet.cpp:217–250

	}

	void IP_Packet::CalculateChecksum()
	{
		//if (!(i == 5)) //checksum field is 10-11th byte (5th short), which is skipped
		ReComputeHeaderLen();
		u8* headerSegment = new u8[headerLength];
		int counter = 0;
		NetLib::WriteByte08(headerSegment, &counter, (_verHi + (headerLength >> 2)));
		NetLib::WriteByte08(headerSegment, &counter, dscp); //DSCP/ECN
		NetLib::WriteUInt16(headerSegment, &counter, GetLength());

		NetLib::WriteUInt16(headerSegment, &counter, id);
		NetLib::WriteByte08(headerSegment, &counter, fragmentFlags1);
		NetLib::WriteByte08(headerSegment, &counter, fragmentFlags2);

		NetLib::WriteByte08(headerSegment, &counter, timeToLive);
		NetLib::WriteByte08(headerSegment, &counter, protocol);
		NetLib::WriteUInt16(headerSegment, &counter, 0); //header csum

		NetLib::WriteIPAddress(headerSegment, &counter, sourceIP);
		NetLib::WriteIPAddress(headerSegment, &counter, destinationIP);

		//options
		for (size_t i = 0; i < options.size(); i++)
			options[i]->WriteBytes(headerSegment, &counter);

		//Zero alignment bytes
		if (counter != headerLength)
			memset(&headerSegment[counter], 0, headerLength - counter);

		counter = headerLength;

		checksum = InternetChecksum(headerSegment, headerLength);
		delete[] headerSegment;
	}
	bool IP_Packet::VerifyChecksum()
	{
		ReComputeHeaderLen();