title: Linux Bluetooth l2ping with signal strength (without connecting?)
body: <p>For any Linux BlueZ/BT experts here:</p>
  
  <p>I'm looking for a way to "ping" known BT devices (known BDADDR) and if they are in range I'd like to know the approximate signal strength.</p>
  
  <p>I know that I could first run l2ping, then establish a connection to the device and finally check the rssi or link quality if the connection worked without pairing first.</p>
  
  <p>However what I'm looking for is a way of getting the signal strength without connecting to the device first. Perfect would be a signal strength measurement from the l2ping reply packet, but I don't know if that info is available at all and passed along the stack.</p>