I am extremely interested in this problem as well and would be very interested in collaborating.
I tried to solve this by porting JSocket Wrench, http://jswrench.sourceforge.net/
, which has a TCP and UDP sniffer (although I was only actually trying to port the Traceroute class).
Anyway, I wasn't successful porting it but I will admit that I didn't try very hard, I just don't have all that much free time right now.
The porting wasn't successful because of an UnsatisfiedLinkError, which I've never seen before. Apparently, there is no native implementation of _socket in Android. Not sure what to do about that.