UDP communication between PC and Android via ethernet
I think reverse tethering would solve your problem. 

Android reverse tethering steps:

Note: Works only in a rooted Android phone.


Connect Android device via USB. 
Enable USB tethering. To do so, go to Settings &rarr; More... &rarr; Tethering &amp; mobile hotspot &rarr; Usb tethering.
On host machine, type: 

$ ifconfig usb0 10.42.0.1 netmask 255.255.255.0 
$ echo 1 &gt; /proc/sys/net/ipv4/ip_forward 


Command for sudo will be: 

$ sudo 'echo 1 &gt; /proc/sys/net/ipv4/ip_forward' 

On Android device (for this step you must install ADB on host PC), type:

$ adb shell 
$ su 
$ netcfg rndis0 dhcp


If it does'nt get the IP address then assign it manually: 

$ netcfg rndis0 10.42.0.2 netmask 255.255.255.0 
$ route add default gw 10.42.0.1 dev rndis0 



Now internet would be working in the Android phone. 

To check , try the command ping www.google.com.

It works for me.