OSX Equivalent of Winsock LSP

On Windows, it's possible to program an LSP service on top of Winsock which provides the ability to do a lot开发者_如何学Python of manipulation/etc. with networked applications. For instance, some anti virus applications register an LSP and analyse network traffic that way. Is there a friendly way to accomplish the same sort of thing on OSX?

IPFW (same/similar to IPFW in other BSDs) is the Mac OS X firewall: http://developer.apple.com/mac/library/documentation/Darwin/Reference/ManPages/man8/ipfw.8.html

Depending on what you're after you may want to look into using divert: http://blog.loudhush.ro/2008/06/using-divert-sockets-to-log-http.html

http://developer.apple.com/mac/library/documentation/Darwin/Reference/ManPages/man4/divert.4.html