UDP Ports used by an Android Application

I am trying to figure out how to get a complete list of UDP ports opened by a specific PID within a given time interval, on and Android Device. In my current solution I am using a combination of busybox lsof and the /proc/net files.

While /proc/net/tcp, /proc/net/tcp6, /proc/net/udp6 are populated by the kernel, /proc/net/udp is always empty. Is there any reliable alternatives to find UDP sockets opened on Android?

Device: Nexus 5 - Rooted

Android: 4.4.4

Kernel: 3.4.0-gd59db4e android-build@vpbs1.mtv.corp.google.com #1