How to enable or disable data transfer depending on the Internet connection method used on Android?

Question

Android

I would like to make sure that when connected to familiar wi-fi networks, everything works as usual: there is Internet access, everything is transmitted, everything is received.
When connecting to unfamiliar wi-fi networks, both open and encrypted, no data is transmitted through them until the VPN connection is established. How to connect via VPN - all traffic through it. Including traffic from system processes. The connection to the VPN is broken - all traffic is blocked again and again we are trying to connect to the VPN server ...
At the same time, I want all this to be configured quite flexibly. So that you can specify any VPN server, edit the lists of networks, so that you can create rules for cellular communications ...
It seemed to me that this is a rather urgent task and there are ready-made solutions for this. But I couldn't find anything. I found special programs that come with a paid VPN service and are "sharpened" for it. I looked in the direction of different firewalls, but it seemed to me that there was no such functionality there. I read about Tasker, but it doesn't fit either ...
The phone has cyanogenmod 11.0, so there is root. Cyanogen itself has VPN support, but I understand that if you turn it on, the phone will always establish a VPN connection. It seems to me that this will degrade the connection through the mobile network in case of a bad signal and on the move. The connection to the VPN server will often be broken and re-established and there will be no connection at all. Yes, and I need to constantly go through the VPN. I'm just paranoid about public hotspots...
Has anyone found a solution?

Answer 1

Use llama, dude!
https://play.google.com/store/apps/details?id=com....