title: Scapy - retrieving RSSI from WiFi packets
body: <p>I'm trying to get RSSI or signal strength from WiFi packets.
  I want also RSSI from 'WiFi probe requests' (when somebody is searching for a WiFi hotspots).</p>
  
  <p>I managed to see it from kismet logs but that was only to make sure it is possible - I don't want to use kismet all the time.</p>
  
  <p>For 'full time scanning' I'm using scapy. Does anybody know where can I find the RSSI or signal strength (in dBm) from the packets sniffed with scapy? I don't know how is the whole packet built - and there are a lot of 'hex' values which I don't know how to parse/interpret.</p>
  
  <p>I'm sniffing on both interfaces - wlan0 (detecting when somebody connects to my hotspot), and mon.wlan0 (detecting when somebody is searching for hotspots).
  Hardware (WiFi card) I use is based on Prism chipset (ISL3886). However test with Kismet was ran on Atheros (AR2413) and Intel iwl4965.</p>
  
  <p>Edit1:</p>
  
  <p>Looks like I need to access somehow information stored in PrismHeader:
  <a href="http://trac.secdev.org/scapy/browser/scapy/layers/dot11.py">http://trac.secdev.org/scapy/browser/scapy/layers/dot11.py</a>
  line 92 ?</p>
  
  <p>Anybody knows how to enter this information?
  packet.show() and packet.show2() don't show anything from this Class/Layer</p>
  
  <p>Edit2:</p>
  
  <p>After more digging it appears that the interface just isn't set correctly and that's why it doesn't collect all necessary headers.
  If I run kismet and then sniff packets from that interface with scapy there is more info in the packet:</p>
  
  <pre><code>###[ RadioTap dummy ]###
    version= 0
    pad= 0
    len= 26
    present= TSFT+Flags+Rate+Channel+dBm_AntSignal+Antenna+b14
    notdecoded= '8`/\x08\x00\x00\x00\x00\x10\x02\x94\t\xa0\x00\xdb\x01\x00\x00'
    ...
  </code></pre>
  
  <p>Now I only need to set the interface correctly without using kismet.</p>