DD-WRT Open VPN Client Help

I need my DD-WRT Router to be able to connect to a OpenVPN Client and if it gets disconnected at all it needs to stop internet access. This needs to be set on startup so a startup script will probably need to be done but im not sure, im not that knowledgeable for DD-WRT OpenVPN Client. If the router is rebooted it MUST connect to the OpenVPN Client before it connects to the internet. if it does not then it must keep retrying or until i disable the OpenVPN Client function.