RVI = Remote Virtual Interface
Using RVI, you can capture network packages in iOS using any normal package capturing tools like tcpdump
etc.
% rvictl -s <your iOS device UDID>
% rvictl -s bad141a1910a406fa964e110a0ff59760d0 // my iPhone 4S<without last few characters>
sudo tcpdump -i rvi0 -n -vv