This app was mentioned in 4 comments, with an average of 1.25 upvotes
There are multiple Android Apps that can bring up an OpenVPN tunnel. I use the paid version of this which works really well and correctly routes local traffic locally.
Not sure, haven't tried SSTP. But I see there is a version of OpenVPN which says it supports IPv6.
https://play.google.com/store/apps/details?id=it.colucciweb.free.openvpn
Sure, I can see the lack of root privileges stopping the app from opening a raw socket. Although I am curious how Facebook does it, as I understand they run their own stack and open a raw socket for network connectivity.
I'm actually using https://play.google.com/store/apps/details?id=it.colucciweb.free.openvpn (well, the paid version of this.)
open vpn try this app