catnip is a tiny network packet mirroring tool. The server (source) is not based on libpcap and, when compiled and stripped, makes the binary smaller than 20kiB. This makes it very suitable for embedded environments where a libpcap-based tool, typically 100kiB for just libpcap and 500kiB for tcpdump, would be simply too large.
What makes catnip stand out from other small packet capturing tools is that it presents the remote systems interface as a local TUN/TAP interface, but additionally can apply a BPF filter at the remote end to send to you only the traffic you are interested in.
