Yes you can use it in China. its LAN multiplayer so if you have two computers connected to the same network then you can connect them..
Viewing post in UDP Lan Multiplayer source code comments
Because it uses files to communicate with coppercube game it is more just for testing and for fun ( constant file read/write probably not good for hard drive either so this method is not good) , for real multiplayer developer must code networking part in c++ with Coppercube Studio version.
client and server code can be modified so it will be healthy to use for turn based or rts games.