Packet Sniffer Construction, Part II – The second installment of the “Packet Sniffer Construction” series off whitepapers by Chad Renfro. Includes good code and excellent, detailed descriptions.
You can download it from the following link: https://packetstormsecurity.com/files/download/14415/Sniffer2.txt
Source: https://packetstormsecurity.com/files/14415/Sniffer2.txt.html