Android VPN Client

[Smart781]

Hello! I am writing an Outline VPN client for Android in the Go language. I managed to write a client for desktop systems, but on Android I had the following problem. I use outline-go-tun2SOCKS (https://github.com/Jigsaw-Code/outline-apps/tree/master/client/go). In order to connect with the server on Android, I need a TUN file descriptor (https://github.com/Jigsaw-Code/outline-apps/blob/master/client/go/outline/tun2socks/tunnel_android.go#L43) is created on Android using VpnService (https://developer.android.com/reference/android/net/VpnService). But it cannot be launched from Go (https://pkg.go.dev/github.com/eycorsican/go-tun2socks-android), so I try to use Gomobile Bind (https://pkg.go.dev/golang.org/x/mobile/cmd/gobind) to create a method working on Go and calling vpnservice, which is made
on Kotlin. However, during the compilation of Gomobile Bind, errors occur. I asked this question on another forum and was suggested to use RunNative to access OS level APIs, but I will be glad to any solutions. Could you please, help me with that? Any help would be much appreciated!!

[jyyi1]

Hi @Smart781 ,

I think the go-tun2socks-android is not maintained any more.

Here are two potential solutions you might want to consider:

• You could try gomobile's reverse binding to call VpnService from Go.
• If reverse binding doesn't work, you may also try exporting VpnService through C using the Java Native Interface (JNI). Then, you can leverage cgo in Go to call these exported C functions.