wpa_supplicant in adhoc WPA-PSK mode

Teh Kok How khteh
Sat Jan 16 00:01:19 PST 2010

	I am using Atheros AR5414 PCI card and have been trying to bring up
the WDS point-to-point link with 128-bit AES encryption. I believe adhoc
mode is close to what I intend to do. So I configured wpa_supplicant-0.7.0
with CONFIG_IBSS_RSN and using the following config file on the targets:

[root at OpenWrt:/tmp/root 1]# cat /var/run/wpa_supplicant-ath0.wds0.conf
        ssid="OpenWrt WDS"
[root at OpenWrt:/tmp/root 1]#
ath0.wds0  IEEE 802.11a  Mode:Repeater  Frequency:4.9 GHz
          Access Point: 06:30:1A:41:21:7A   Bit Rate=54 Mb/s   Tx-Power:17
          RTS thr:off   Fragment thr:off
          Encryption key:8D01-F10E-BC3E-A568-1A38-4A60-FF4A-BB5D   Security
          Power Management:off
          Link Quality=0/70  Signal level=-96 dBm  Noise level=-96 dBm
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

[root at OpenWrt:/tmp/root 1]# iwlist ath0.wds0 keys
ath0.wds0  3 key sizes : 40, 104, 128bits
          4 keys available :
                [1]: 8D01-F10E-BC3E-A568-1A38-4A60-FF4A-BB5D (128 bits)
                [2]: off
                [3]: off
                [4]: off
          Current Transmit Key: [1]
          Security mode:restricted

[root at OpenWrt:/tmp/root 1]#

	While both target share the same key now, they don't ping each
other. However, `ifconfig` does show that the "ath0.wds0" virtual interface
is receiving 2 packets and "wifi0" 1 packet every second the other end is
sending out ICMP ping packet. Nevertheless, there is no ICMP response from
the RX end. `tcpdump -vvv` at the RX end shows "Unknown SSAP > Broadcast
Unknown DSAP" messages.
	Any idea where are the missing pieces in my setup or wpa_supplicant
or driver?

-----Original Message-----
From: hostap-bounces at lists.shmoo.com [mailto:hostap-bounces at lists.shmoo.com]
On Behalf Of Jouni Malinen
Sent: Saturday, January 16, 2010 3:42 PM
To: hostap at lists.shmoo.com
Subject: Re: wpa_supplicant in adhoc WPA-PSK mode

On Fri, Jan 15, 2010 at 04:12:02PM -0600, LAMBA Jaideep wrote:

> Jouni: I can commit some time to driver development so 4-way handshake
> and related security features and wpa_supplicant work with it. Can you
> briefly explain what we are missing in drivers before I start digging
> in. Also is there a preferred driver that is better suited to this
> purpose ??

The main missing part is support for multiple GTKs (i.e., one group key
for each peer to receive broadcast/multicast frames from it) and
testing. Getting support for this into nl80211 and mac80211 would be a
good start in allowing many drivers to use this.

Jouni Malinen                                            PGP id EFC895FA
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