[PATCH] hostapd: Advertise OBSS scan params based on driver capability

[Rajkumar Manoharan]

On Tue, May 06, 2014 at 08:02:49AM -0700, Paul Stewart wrote:
>    Hi Rajkumar!  This functionality was originally added in order to allow
>    testing of OBSS functionality in clients of the AP.  In particular, there
>    wasn't a built in stipulation that the AP hardware / firmware support OBSS
>    action frames.  I don't mind having hostapd's default behavior being
>    predicated on the hardware being capable -- for example, you could set
>    obss_interval to 300 conditional on that hardware capability, but it would
>    be nice to preserve the ability to manually set this interval in the
>    configuration file regardless of the underlying hardware capability.
>
Paul,

Still it allows the user to overwrite obss_interval manually by config_file.

>      diff --git a/src/ap/ieee802_11_ht.c b/src/ap/ieee802_11_ht.c
>      index c0a7cd4..7020858 100644
>      --- a/src/ap/ieee802_11_ht.c
>      +++ b/src/ap/ieee802_11_ht.c
>      @@ -46,7 +46,8 @@ u8 * hostapd_eid_ht_capabilities(struct hostapd_data
>      *hapd, u8 *eid)
> 
>              pos += sizeof(*cap);
> 
>      -       if (hapd->iconf->obss_interval) {
>      +       if (hapd->iconf->obss_interval &&
>      +           (hapd->iface->drv_flags & WPA_DRIVER_FLAGS_HT_2040_COEX)) {
>                      struct ieee80211_obss_scan_parameters *scan_params;
>

Since AP side functionalities are recently added, OBSS scan trigger
interval is assigned with default and obss IE will be appended in beacon/probe resp
based on driver capabilities. Earlier the OBSS IE is added if obss_interval is
non-zero eventhough the driver does not support OBSS funtionalities.

Both station and AP mode 20/40 coex functionalities are validated in ath9k driver.

-Rajkumar