I am not sure if this will work but it may be worth a try:
http://www.countryipblocks.net/When I first started using endian, I noted there was a considerable amount of traffic coming in from Asia-pac/China. I blocked China by posting the complete cidr list from this site in incoming routed traffic and blocking it.
example
1.12.0.0/14
1.24.0.0/13
1.48.0.0/15
For the most part it worked. once in a while somethng may get through but noticed there has been a lot less activity since I have done that.
Please let me know if it works for you? It would be validation for me as well.