hostap scanning is limited?

Don Park don
Sat Jun 14 11:56:15 PDT 2003


The scanning support added into Linux Wireless Extensions v14 gives one
great advantage over the monitor-mode based scanning. One can stay
connected to an access point while still doing occasional scans for new
APs in the area. Ive started a GTK app to make use of this feature
apradar.sourceforge.net

Ive been using the aironet drivers for some time with great success but
now i want to make sure it works with hostap as well. from this simple
test it looks like hostap cannot be associated and still do wireless
scanning. Is this something that will be fixed? is there a workaround that
I can use?

[root at localhost wireless_tools.25dgp]# iwconfig wlan0 mode managed essid any
[root at localhost wireless_tools.25dgp]# iwlist wlan0 scanning
wlan0     Scan completed :
          Cell 01 - Address: 00:04:5A:0E:5F:2E
                    ESSID:"www.personaltelco.net"
                    Mode:Master
                    Frequency:2.462GHz
                    Quality:0/92  Signal level:-96 dBm  Noise level:-99 dBm
                    Encryption key:off
                    Bit Rate:1Mb/s
                    Bit Rate:2Mb/s
                    Bit Rate:5.5Mb/s
                    Bit Rate:11Mb/s

[root at localhost wireless_tools.25dgp]# iwconfig wlan0 mode managed essid abcd
[root at localhost wireless_tools.25dgp]# iwlist wlan0 scanning
wlan0     No scan results

Even though ive set the essid to something specific, the scanning should
still be picking up access points.

Also scanning in master mode doesnt work. Ive poked through the hostap
code and found this interesting comment in hostap_ioctl.c, line 1473.

         * Master mode would need to drop to Managed mode for a short
while
         * to make scanning work.. Or sweep through the different channels
and
         * use passive scan based on beacons. */

it looks like someone was intending for scanning to work while in master
mode. Is this a bug?

Don
-- 
** irc: irc.freenode.net nick: don-o channels: #wireless, #java
** Create more, consume less.
** Wireless engineers do it 2.4 billion times per second.




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