I'm a bit confused and lost on how this App is working called Ha Tunnel Plus (You can check it on Playstore, and have a look on YouTube for the configuration file). Basically it somehow uses the internet connection of the server, it tunnels it to your Android device and you can be connected to the internet without having data on your mobile network sim card, but you can use internet just like you would normally do except that this is not limited on how much data you as a user is using.
I tried playing around with the bunch of source codes I found on github but they don't connect, so since I was trying to connect using on of the IP address that worked on Ha Tunnel Plus, I thought it would also work in my App but it didin't, and I thing that .hat configuration file is the certificate because I found some encrypted data but it just text.
In my case I want to be able to limit this internet access only to my App, also be able to dynamically change this so the entire phone can use it. I don't want a user to select the countries nor see it rather randomly do that at the background, but first thing first. for this kind is it reversing internet connetion or what? How does this work exactly because others I saw they work only if you have data otherwise it doesn't connect. Another that I saw from YouTube to be working is NPK Tunnel, TLS Injector. Anyone know how these Apps work?