Google Backup does not work on Wi-Fi while on VPN

[atkrv]

Android 8.1.0 can't route Wi-Fi while on VPN. Reproduced even with NoRoot Firewall.

Steps to reproduce

1. Install and enable any VPN app
2. Try to auto-backup photos in Google Photos or stream music in Play Music (Stream only on Wi-Fi setting must be ON)

Expected behavior

Apps should work with no network errors

Actual behavior

Google Photos can't backup any photos with Waiting for Wi-Fi message. Play Music can't stream any song with Can't prepare radio. Please try againg. message.

Screenshots and video:

VIDEO
https://uploads.adguard.com/up01_dj4zx_device-2017-11-13-203520.mp4

Logs

Archive.zip

Customer ID

1656541, 1691627

Your environment

• Adguard version: 2.10.164
• Adguard filtering mode: VPN
• Device model: Google Nexus 6P
• Android 8.1.0
• Not rooted

[ameshkov]

@altokarev report it to Google please

[atkrv]

Reported already: https://issuetracker.google.com/issues/69011592, https://issuetracker.google.com/issues/68657525

[crispinb]

The Android team in their wisdom have decided not to fix this until some 'future release'. This unfortunately makes Adguard unusable on Android. Presumably they have decided to force ads on Android users.

[ameshkov]

I wonder would it help to disable filtering for Google apps in AdGuard's apps mgmt settings?

Photos, Play Music, etc.

[crispinb]

@ameshkov Good thought -- I've never got round to exploring the Android Adguard settings. Just tried it and is promising so far. Background upload of one test photo just worked with Adguard enabled. That's not enough of a test to be certain it works under all circumstances (eg does Photos offload jobs to Google Play Services when in the background?) but looks good. Thanks.

[ameshkov]

Okay, this is now officially our bug:)

Google closed the original issue as Won't Fix (Intended Behavior)

When a VPN is up the OS has no way to guarantee that network traffic will go on wifi. The VPN app could decide to send and receive traffic on any available interface, including cell data. Recent changes to the VPN code have made it so that if the VPN calls setUnderlyingNetworks, the networking APIs will reflect some of the properties of the underlying networks (e.g., whether they are metered or not) into the VPN's networkcapabilities. But it's up to the podcast app to use the required APIs, such as isActiveNetworkMetered.

What we should do now

On Oreo, we should be calling VpnService.setUnderlyingNetworks when the tunnel is established and VpnService.Builder.setUnderlyingNetworks when we're preparing the tunnel.

[Revertron]

Aha, and we can pass null to let the system know, that we are not binding to particular interface.
I think it will be easy.

[TPS]

Fair warning, FYI: If y'all read the rest of the issue thread where that last quote comes from, not even the existing official GApps implement this functionally, so perhaps not so easy/simple. 🤦🤷‍♂️🤔