The reason
I found that my VPN app has a bug that when disconnecting the VPN from settings (Network & internet -> VPN), my VpnService wouldn’t be killed.
Finally, I got the cause, it’s because the VpnService.onRevoke() was not called when the VPN was killed from settings.
So I was thinking, is there any way to listen VPN connection in Android?
Here is what I got:
Listen VPN connection using ConnectivityManager
Close the VPN connection when onLost was called.
// In VpnService
// Callback
private val networkCallback = object : NetworkCallback() {
override fun onAvailable(network: Network) {
Log.i("Network onAvailable: ")
}
override fun onLost(network: Network) {
Log.i("Network onLost: ")
// Do something to stop VPN
}
}
// Start listen VPN connection
override fun onCreate() {
val request = NetworkRequest.Builder()
.addTransportType(TRANSPORT_VPN)
.removeCapability(NET_CAPABILITY_NOT_VPN)
.removeCapability(NET_CAPABILITY_INTERNET)
.build()
getSystemService(ConnectivityManager::class.java)
.registerNetworkCallback(request, networkCallback)
}
// Stop listen VPN connection
override fun onDestroy() {
getSystemService(ConnectivityManager::class.java)
.unregisterNetworkCallback(networkCallback)
}
Call onRevoke when onTransact was triggered in Binder
Also, I can use onTransact to close the VPN connection when users disconnect the VPN from settings.
I’m using a customized Binder for communicating to my VpnService, it will trigger the onTransact when the VPN was killed from settings.
override fun onTransact(code: Int, data: Parcel, reply: Parcel?, flags: Int): Boolean {
if (code == IBinder.LAST_CALL_TRANSACTION) {
onRevoke()
return true
}
return super.onTransact(code, data, reply, flags)
}
