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Problem obtaining WiFi info from Radiotap

Problem obtaining WiFi info from Radiotap

From:
Jose Saldana
Date:
2015-09-02 @ 11:08
Hi all,
 
We are using Click to capture 802.11 packets. We first run RadiotapDecap,
and then ExtraDecap. However, the information we obtain is not correct.
 
We have added some printf lines in radiotapdecap.cc (lines 147 and
subsequent), and we can conclude:
 
- The information about the elements that are present (or not) is correct.
- The information in those elements is not correct.
 
We always obtain these two values, even if we move away from the AP:
rate: 8
signal: 0
 
 
However, if we use tcpdump in the same machine, we can see the radiotap
information: the rate is 11.0Mb/s and the signal is -22dB (it varies between
packets):
 
09:55:30.989661 2759273455us tsft 11.0 Mb/s 2437 MHz 11g -22dB signal [bit
29] DA:Broadcast BSSID:00:0f:f7:80:1a:31 

 
 
We are running Click in a TP-Link 1043ND v2 AP:
http://wiki.openwrt.org/toh/tp-link/tl-wr1043nd (Qualcomm Atheros
QCA9558@720MHz).
 
 
Thanks in advance!
 
Jose Saldana
University of Zaragoza