Develop Reference

Detect if an always-on VPN is configured on Android

I have an Android VPN application. When I fire the intent to start the VPN (via VPNService.prepare), it fails immediately if there's an always-on VPN already configured on the device. That seems reasonable, but I'd like to be able to easily detect that case, so I can show a helpful message to the user.
By 'always on' I mean the specific VPN always-on Android VPN flag: https://developer.android.com/guide/topics/connectivity/vpn#always-on
I can't seem to find a way to access that info, even though it is used internally in Android (e.g. here but that getAlwaysOnVpnPackage doesn't seem to be available publicly AFAICT).
The best option I've seen is Check if a VPN connection is active in Android?, which will tell you if any VPN connection is currently active, but that's not enough, because:
I don't want to know about temporary VPN connections: I'm only interested if it's an always-on VPN connection.
Sometimes 'always-on' connections aren't actually always on. If you have a disconnected connection and set it as 'always-on', it's configured as such, and blocks all other VPN installs, but there's no network connection created (Android shows a persistent warning instead, which takes you to the other app to activate the connection). Because there's no connection, the above technique doesn't work. I still need to detect this case, since it still blocks my VPN setup.
Is there any way to check whether the device currently has a VPN configured as 'always-on'?

You can use this method
private fun isVpnAlwaysOn(): Boolean {
return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP_MR1) {
val alwaysOn = Settings.Secure.getString(contentResolver, "always_on_vpn_app")
return !alwaysOn.isNullOrEmpty()
} else false
}
'alwaysOn' contains the package name of the app for which always-on is configured.

In the end, it seems this isn't possible on a normal device any way that I can find. I think is possible if you're a device admin, but that requires managed enterprise devices etc.
For now, I've handled this by watching for near-instant (less than 200ms) VPN setup failures (between running startActivityForResult(vpnIntent) and receiving onActivityResult with RESULT_CANCELED) and then showing a helpful message in that case.
Full implementation is in https://github.com/httptoolkit/httptoolkit-android/commit/928fbf92a4f868042789471be0d42800a226194b in case you're trying to do the same.

How to save EAP wifi network in Android 10 after Android Enterprise provisioning

Up to API lvl 29 we have been using WifiConfiguration to set up wifi connections with our DPC (both device and Profile Owner modes). Since API lvl 29 we can still save Open, WEP, WPA networks, but any attempt of saving EAP network is completely ignored. We tried to use WifiSuggestions method and the suggestion is properly displayed in the notification bar, but when the user taps on "allow" - nothing happens. There are no errors in the log, addNetworkSuggestions() method returns STATUS_NETWORK_SUGGESTIONS_SUCCESS.
This problem exists only when our DPC is provided Device/Profile Owner permissions with full provisioning process (work profile creation or fully managed during the first start). Getting Device Owner status using ADB lets us save the network by allowing the network suggestion.
This is how we set up the network suggestion:
#RequiresApi(api = Build.VERSION_CODES.Q)
public static WifiNetworkSuggestion setupWifiNetworkSuggestion (WifiConfiguration wifiConfiguration){
return new WifiNetworkSuggestion.Builder()
.setSsid(wifiConfiguration.SSID)
.setIsHiddenSsid(wifiConfiguration.hiddenSSID)
.setWpa2EnterpriseConfig(wifiConfiguration.enterpriseConfig)
.build();
}
after that we call:
List<WifiNetworkSuggestion> networkSuggestionList = new ArrayList<>();
networkSuggestionList.add(setupWifiNetworkSuggestion(wifiConfiguration));
int status = mWifiManager.addNetworkSuggestions(networkSuggestionList);
if (status != WifiManager.STATUS_NETWORK_SUGGESTIONS_SUCCESS) {
_logger.error("Problem adding network suggestion, status code: " + status);
}
Are we missing something? The same code works in our other app where we do not use EMM provisioning to get Device Owner. All the requested permissions are the same in both apps. We tried to get some error info or set up some logs but we only get success statuses all the way.

We finally made it work! The problem was caused by three separate issues:
We were lacking allowed key management setting WifiConfiguration.KeyMgmt.WPA_EAP
Our test RADIUS server rejects connection attempts when any domain is provided in the enterprise config. It was giving us unnecessary disconnections even at the point when we resolved Android-side issues
MOST IMPORTANT: For some reason our password policy was not enforced and on test environment we use self-signed certificates. Without at least PIN-lock set up on the device, the certificates cannot be attached to the network profile, therefore it cannot be added/connected to. Even if the network is saved, it lacks the certificate which has to be selected manually (it is deployed properly to the certificate store, though)

WiFi networks added through addNetworkSuggestions do not appear on the system-provided list of saved WiFi networks. But if the device sees the WiFi, it will add a note that this network was suggested by this and that app. Then the user can connect with the WPA Enterprise credentials configured in the code.
From my understanding, it is expected behavior that nothing happens that the user could see.
Also, if you uninstall the app, the suggested networks disappear again.
As a Device Owner, you should be able to use the otherwise deprecated WifiManager.AddNetwork() method to add the network to the system list. I haven't tested that myself.
On Android 12 (but not with 10 and 11), you can ask the user to add a network to the system list using this code:
var suggestionsList = new WifiNetworkSuggestion[]
{
networkSuggestion
};
Bundle bundle = new Bundle();
bundle.PutParcelableArrayList(
Android.Provider.Settings.ExtraWifiNetworkList,
suggestionsList
);
Intent intent = new Intent(Android.Provider.Settings.ActionWifiAddNetworks);
intent.PutExtras(bundle);
intent.AddFlags(ActivityFlags.NewTask);
Android.App.Application.Context.StartActivity(intent);

Which method is called when someone tries to connect using WifiP2PManager.connect(Channel, WifiP2pConfig,ActionListener)?

I am tring to setup WIFI P2P on 2 devices using
manager.addLocalService(channel, service, ActionListener)
and then connect both devices using
manager.connect(channel, config, ActionListener).
I would like to know which method is called before the popup to accept/reject connection is shown on the target device. All I was able to find was onConnectionInfoAvailable(WifiP2pInfo p2pInfo), but it is called after the connection is established.
I basically want to receive the "instance name" of the device trying to connect to me using WIFI P2P and then reject the connection request without showing system dialog(that allows the user to accept/reject connection).
I can't anything that can help me do this on docs or any other place. If anyone knows how to do it or can point me in the right direction then please let me know.

I solved it. I can put the instancename and devicename (of device I want to connect to) in Map that is passed when setting up service. From other device I can retrieve map of all devices available using this and find the instancename of one I need.

TXT Record from a Wifi Direct Printer

I'm trying to get TXT Records from Wifi Direct Printers nearby. So far, I can discover peers and establish a connection. But no luck with TXT Records.
I tried Wifi Direct Service Discovery, and I believe I did everything properly since I compared lots of codes from different resources including sample projects from Google and some open source Wifi Direct Wrappers in GitHub. But I couldn't make it work.
I've also seen some weird issues while trying to achieve that. e.g in some devices, when I start the peer discovery, Wifi Connection started to be turned off and on constantly.
Can someone explain how this actually works ? are DnsSdServiceResponseListener and DnsSdTxtRecordListener made for Android devices rather than Printers ?
I've also tried to listen the MultiCast DNS IP Address (224.0.0.251) with a MulticastSocket after establishing the connection between Android and Wifi Direct Printer, but I couldn't receive any data as well.
Thanks.

I used "DnsSdServiceResponseListener" and "DnsSdTxtRecordListener" successfully in my current project. Both listeners are associated to discovering local services nearby.
To use them properly, you have to do the following:
Implement your listeners
WifiP2pManager.DnsSdServiceResponseListener dnsListener = new WifiP2pManager.DnsSdServiceResponseListener() {
#Override
public void onDnsSdServiceAvailable(String instanceName, String registrationType, WifiP2pDevice device) {
// instanceName is service name and device is the print information
}};
WifiP2pManager.DnsSdTxtRecordListener txtListener = new WifiP2pManager.DnsSdTxtRecordListener() {
#Override
public void onDnsSdTxtRecordAvailable(String fullDomain, Map record, WifiP2pDevice device) {
// here we get the service published information in the record map object
}};
Add the listeners to your WiFiManager object
wifiP2PManagerObj.setDnsSdResponseListeners(mChannel, dnsListener, txtListener);
Add service request
WifiP2pDnsSdServiceRequest serviceRequest = WifiP2pDnsSdServiceRequest.newInstance();
wifiP2PManagerObj.addServiceRequest(mChannel,serviceRequest, actionListener);
Finally, discover services
wifiP2PManagerObj.discoverServices(mChannel,actionListener);
After discover services is executed successfully, the listeners should receive the nearby services information.
Hope this helps.
Goodluck.
Update
Wifi direct supported printers don't have any published services by default. To use them you have to connect to them via wifi direct and print normally as its a printer connected to your network. Note that those listeners are meant to capture published services (i.e will not capture anything for any device unless its publishing a service).

I think you will need to run Bonjour discovery once the connection is established. You can see NSD and look for "_ipp._tcp" as the service type. By the way,
for "I've also seen some weird issues while trying to achieve that. e.g in some devices, when I start the peer discovery, Wifi Connection started to be turned off and on constantly." if you're testing on a 7.1 device you might be seeing this issue, for which a patch should be coming soon.

Nearby Connections no ConnectionResponseCallback

I'm using Nearby Connections API in Android. It's working fine except cases where there is a sudden disconnections.
The client again succeed in finding the endpoint, using the discovery process, yet when he uses sendConnectionRequest() Connections.ConnectionResponseCallback never called no matter if I restart the app both on the client and on the endpoint. Only when I restart both devices the connection start to work again.
I have 20+ devices on the client side so there might be connection between the two things.
Any help on issue or where to start debugging the issue would be great.

For making a connection in Nearby Connection API, the client don't just sends connection request, but Host also has to accept it-
Nearby.Connections.acceptConnectionRequest(mGoogleApiClient, remoteEndpointId, myPayload, this);
or reject it-
Nearby.Connections.rejectConnectionRequest(mGoogleApiClient, remoteEndpointId);
try this, and in your connection response callback have conditions to do stuff
if(status.isSuccess()){
// Successful connection
} else {
// Failed connection
}
Hope it helped

You need to properly disconnect the connection when needed with;
Nearby.Connections.disconnectFromEndpoint(mGoogleApiClient, remoteEndpointId);
or;
Nearby.Connections.stopAllEndpoints(mGoogleApiClient);
https://developers.google.com/nearby/connections/android/manage-connections