What API (or lib) do I should use to sniff local network ports on Mac OS X (Cocoa)?

I'm trying to make a simple HTTP sniffer (like HTTPFox) development testing purpose. HTTPFox is good enough, but I should automate some kind of test. (No detail yet) But I have no idea how to do this.

What kind of API or libs do I should use to do this on Mac?

Cocoa will be great bu开发者_运维百科t any lower level ways are welcome.

---

Use libpcap/tcpdump. http://www.tcpdump.org/