If you are interested in tcpdump and use it for debugging, you might potentially also be interested in the Bro network monitoring system (http://bro.org).

It gives you very deep visibility in the supported protocols, dumps easy to parse log-files by default (see e.g. https://www.bro.org/sphinx-git/httpmonitor/index.html for HTTP information) - and it is fully scriptable.

(Disclaimer: I am involved with the project.)