cdp-tools is a set of tools for working with the Cisco Discovery Protocol. they were written because of a particular hosting center that insisted on learning routes using CDP, and thusly required Cisco Switches for doing their dirty work. cdp-listen/cdp-routemgr are proof-of-concepts that may be useful if you want to implement a similarly brain-damaged proposal. cdp-send is a must-have tool if you are in that situation. It can pretend to be just about any kind of Cisco hardware you can imagine. the source is a bit difficult to follow as a requirement was that it build under both the ancient libnet and the new libnet code. hence, much nasty macro-ing.