Multiple BSSID problem with hostapd

Multiple BSSID problem with hostapd

[Christian Felsing]

Hello,

I ran into problems configuring multiple BSSID in hostapd, because
hostapd is running in an error. My intention is to set up one public
ssid and one private ssid. I think it is a configuration problem, but
neither Google nor http://linuxwireless.org/ gives a hint.

I did following steps:

debian:~# iw reg set DE
debian:~# ip link set wlan0 addr 00:15:6d:84:0e:00

...works so far

config file /etc/hostapd/hostapd.conf contains following content:

interface=wlan0
bridge=br0
driver=nl80211
ieee80211n=1
ht_capab=[SHORT-GI-40][DSSS_CCK-40][HT40-][HT40+][HT20]
ctrl_interface=/var/run/hostapd
ctrl_interface_group=0
ssid=cftest
country_code=DE
ieee80211d=1
hw_mode=g
channel=1
beacon_int=100
dtim_period=2
max_num_sta=255
rts_threshold=2347
fragm_threshold=2346
macaddr_acl=0
auth_algs=3
ignore_broadcast_ssid=0
wme_enabled=1
wme_ac_bk_cwmin=4
wme_ac_bk_cwmax=10
wme_ac_bk_aifs=7
wme_ac_bk_txop_limit=0
wme_ac_bk_acm=0
wme_ac_be_aifs=3
wme_ac_be_cwmin=4
wme_ac_be_cwmax=10
wme_ac_be_txop_limit=0
wme_ac_be_acm=0
wme_ac_vi_aifs=2
wme_ac_vi_cwmin=3
wme_ac_vi_cwmax=4
wme_ac_vi_txop_limit=94
wme_ac_vi_acm=0
wme_ac_vo_aifs=2
wme_ac_vo_cwmin=2
wme_ac_vo_cwmax=3
wme_ac_vo_txop_limit=47
wme_ac_vo_acm=0
eapol_key_index_workaround=0
eap_server=0
own_ip_addr=127.0.0.1
bss=wlan0_0
ssid=taunusstein.net

after starting hostapd with that config following happens:

debian:~# hostapd -ddd /etc/hostapd/hostapd.conf
Configuration file: /etc/hostapd/hostapd.conf
ctrl_interface_group=0
Opening raw packet socket for ifindex 166465272
BSS count 2, BSSID mask ff:ff:ff:ff:ff:fe (1 bits)
SIOCGIWRANGE: WE(compiled)=22 WE(source)=21 enc_capa=0xf
nl80211: Added 802.11b mode based on 802.11g information
Allowed channel: mode=1 chan=1 freq=2412 MHz max_tx_power=20 dBm
Allowed channel: mode=1 chan=2 freq=2417 MHz max_tx_power=20 dBm
Allowed channel: mode=1 chan=3 freq=2422 MHz max_tx_power=20 dBm
Allowed channel: mode=1 chan=4 freq=2427 MHz max_tx_power=20 dBm
Allowed channel: mode=1 chan=5 freq=2432 MHz max_tx_power=20 dBm
Allowed channel: mode=1 chan=6 freq=2437 MHz max_tx_power=20 dBm
Allowed channel: mode=1 chan=7 freq=2442 MHz max_tx_power=20 dBm
Allowed channel: mode=1 chan=8 freq=2447 MHz max_tx_power=20 dBm
Allowed channel: mode=1 chan=9 freq=2452 MHz max_tx_power=20 dBm
Allowed channel: mode=1 chan=10 freq=2457 MHz max_tx_power=20 dBm
Allowed channel: mode=1 chan=11 freq=2462 MHz max_tx_power=20 dBm
Allowed channel: mode=0 chan=1 freq=2412 MHz max_tx_power=20 dBm
Allowed channel: mode=0 chan=2 freq=2417 MHz max_tx_power=20 dBm
Allowed channel: mode=0 chan=3 freq=2422 MHz max_tx_power=20 dBm
Allowed channel: mode=0 chan=4 freq=2427 MHz max_tx_power=20 dBm
Allowed channel: mode=0 chan=5 freq=2432 MHz max_tx_power=20 dBm
Allowed channel: mode=0 chan=6 freq=2437 MHz max_tx_power=20 dBm
Allowed channel: mode=0 chan=7 freq=2442 MHz max_tx_power=20 dBm
Allowed channel: mode=0 chan=8 freq=2447 MHz max_tx_power=20 dBm
Allowed channel: mode=0 chan=9 freq=2452 MHz max_tx_power=20 dBm
Allowed channel: mode=0 chan=10 freq=2457 MHz max_tx_power=20 dBm
Allowed channel: mode=0 chan=11 freq=2462 MHz max_tx_power=20 dBm
HT40: control channel: 1  secondary channel: 5
RATE[0] rate=10 flags=0x2
RATE[1] rate=20 flags=0x6
RATE[2] rate=55 flags=0x6
RATE[3] rate=110 flags=0x6
RATE[4] rate=60 flags=0x0
RATE[5] rate=90 flags=0x0
RATE[6] rate=120 flags=0x0
RATE[7] rate=180 flags=0x0
RATE[8] rate=240 flags=0x0
RATE[9] rate=360 flags=0x0
RATE[10] rate=480 flags=0x0
RATE[11] rate=540 flags=0x0
Passive scanning not supported
Flushing old station entries
Deauthenticate all stations
Mode: IEEE 802.11g  Channel: 1  Frequency: 2412 MHz
Using interface wlan0 with hwaddr 00:15:6d:84:0e:00 and ssid 'cftest'
Failed to add BSS (BSSID=00:15:6d:84:0e:01)
wlan0: Unable to setup interface.
Failed to remove interface.


if I remove lines
 bss=wlan0_0
 ssid=taunusstein.net

then hostapd starts and I get at least an unencrypted WLAN and I got
following interfaces:

debian:/usr/src# ifconfig
mon.wlan0 Link encap:UNSPEC  HWaddr
00-15-6D-84-0E-51-77-6C-00-00-00-00-00-00-00-00
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

wlan0     Link encap:Ethernet  HWaddr 00:15:6d:84:0e:00
          inet6 addr: fe80::215:6dff:fe84:e00/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:100 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 B)  TX bytes:9171 (8.9 KiB)

debian:/usr/src# iwconfig
wlan0     IEEE 802.11abgn  Mode:Master  Frequency:2.412 GHz  Tx-Power=20
dBm
          Retry  long limit:7   RTS thr=2347 B   Fragment thr=2346 B
          Power Management:on

mon.wlan0  IEEE 802.11abgn  Mode:Monitor  Frequency:2.412 GHz
Tx-Power=20 dBm
          Retry  long limit:7   RTS thr=2347 B   Fragment thr=2346 B
          Power Management:on

(non relevant interfaces stripped from output)

Clients are able to join network.

My platform:

* Alix 2D3
* Ubiquity SR-71A (driver ath9k from compat-wireless-2009-07-31)
* Debian Lenny
* Kernel 2.6.30.4
* compat-wireless-2009-07-31
* 2009.04.17-regulatory.bin
* crda-1.1.0
* hostapd-0.6.9
* iw-0.9.15

As long as no additional bss is configured, everything works well
including WPA/WPA2 and 802.11n but channels 12/13 - but at this time I
don't care about that missing channels.

Christian

Re: Multiple BSSID problem with hostapd

[Christian Felsing]

After investigating source code following function caused my problem:

static int i802_bss_add(void *priv, const char *ifname, const u8 *bssid)
{
        int ifidx;

        /*
         * The kernel supports that when the low-level driver does,
         * but we currently don't because we need per-BSS data that
         * currently we can't handle easily.
         */
        return -1;

        ifidx = nl80211_create_iface(priv, ifname, NL80211_IFTYPE_AP,
bssid);
        if (ifidx < 0)
                return -1;
        if (hostapd_set_iface_flags(priv, ifname, 1)) {
                nl80211_remove_iface(priv, ifidx);
                return -1;
        }
        return 0;
}

Obviously hostapd does not support multiple SSIDs because that function
returns always an error.

It would be nice to mention that in documentation...

Christian

Re: Multiple BSSID problem with hostapd

[Jouni Malinen]

On Sun, Aug 02, 2009 at 08:33:33AM +0200, Christian Felsing wrote:
> After investigating source code following function caused my problem:
> 
> static int i802_bss_add(void *priv, const char *ifname, const u8 *bssid)
> {
>         int ifidx;
> 
>         /*
>          * The kernel supports that when the low-level driver does,
>          * but we currently don't because we need per-BSS data that
>          * currently we can't handle easily.
>          */
>         return -1;

Some more investigation would show that this does not exist in the
hostapd development branch..

> Obviously hostapd does not support multiple SSIDs because that function
> returns always an error.

That is the case for hostapd 0.6.9. In any case, there are number of new
kernel features that may not be fully supported by the 0.6.x branch and
checking the current development branch (0.7.x) would be a good idea
when advanced AP functionality is desired.

-- 
Jouni Malinen                                            PGP id EFC895FA

Re: Multiple BSSID problem with hostapd

[Christian Felsing]

Works with development branch :-)

regards
Christian

Jouni Malinen schrieb:
> checking the current development branch (0.7.x) would be a good idea
> when advanced AP functionality is desired.
>