Preventing network scans once connected via libnm

[Charles Lohr <charlesl valvesoftware com>]

In our application, we need to maintain connection to an AP and it needs to stay low latency for a variety of reasons.  Whenever networks are scanned, for us they create an unacceptable level of latency (>50ms in many cases) on the connection. 

 

Sometimes we stop NetworkManager from running with `pkill -STOP NetworkManager` and `pkill -CONT NetworkManager` but, for a variety of reasons this is disadvantageous.

 

I’ve seen references to people online saying you can prevent scanning once connected by specifying a BSSID, but I don’t see how that can be done with libnm.

 

Currently we use the following, where path can be gotten from either a scan or `nm_connection_get_path`

 

```
nm_client_activate_connection_async ( m_pClient, conn, (NMDevice*)m_pDevice, sAccessPointPath.c_str(), nullptr, []( GObject* pObj, GAsyncResult* res, gpointer pContext ) {…} );

```

 

What mechanism can we use to specify that a given path should lock it’s BSSID when using NetworkManager via libnm?

 

Second question:  Are there any mechanisms we can use to lock out other apps from requesting scans from NetworkManager?  This solution would be preferred for our application because scans have such a significant impact on the system.  Or is there a way to just outright disable all scanning via NetworkManger for a period of time?

 

Charles Lohr