Bug in wpa_supplicant IBSS mode using disable_HT40 option

[Koen Vandeputte]

Hi All,


When using wpa_supplicant in IBSS mode on 5GHz channels, the 
"disable_ht" & "disable_ht40" parameters are ignored.
Created IBSS links are always fixed to HT40, independent of this 
parameters value.

Currently I use the patch below to force it to HT20.
It seems the wrong case is being selected due to a bug.

The "disable_sgi" parameter does work correctly.



Hardware used for testing:

2x Gateworks Laguna CNS3xxx + AR9280 (UBNT SR71-15)
2x Gateworks Ventana IMX-6 + AR9300 (Compex WLE350NX)



Branch tested:

Master @ June 1st 2016



Following setup:

  * 2 identical devices
  * IBSS mode using wpa_supplicant WPA2    (Config file below)
  * 2 meter apart
  * Tested on all possible 5GHz channels



Patch created to force HT20:

--- a/wpa_supplicant/wpa_supplicant.c
+++ b/wpa_supplicant/wpa_supplicant.c
@@ -1981,6 +1981,9 @@ void ibss_mesh_setup_freq(struct wpa_sup
                         break;
                 }

+               //Force HT20
+               freq->sec_channel_offset = 0;
+
                 wpa_scan_results_free(scan_res);
         }


wpa_supplicant config file:

ctrl_interface=DIR=/tmp/run/wpa_supplicant GROUP=root
update_config=1
ap_scan=2
country=XA
beacon_int=100
network={
     ssid="ROBOT100"
     frequency=5500
     bssid=CC:A5:4B:83:7E:A9
     mode=1
     disable_ht=0
     disable_ht40=1
     disable_sgi=1
     proto=WPA2
     key_mgmt=WPA-PSK-SHA256
     pairwise=CCMP
     group=CCMP
     psk="MyPasswordIsHere"
}


Country XA definition:

country XA: DFS-UNSET
     (2402 - 2494 @ 40), (N/A, 30), (N/A)
     (5180 - 5835 @ 160), (N/A, 30), (N/A)
     (57240 - 63720 @ 2160), (N/A, 40), (N/A)


If more information is required, please let me know.

Thanks,

Koen Vandeputte
nCentric Europe