[RFC] ap: AP/GO interface teardown optimization

[Jouni Malinen]

On Mon, Mar 03, 2014 at 02:08:16PM +0200, Ilan Peer wrote:
> This commit adds an option to optimize AP teardown by leaving the
> deletion of keys (including group keys) and stations to the driver.
> 
> This optimization option should be used if the driver supports stations
> and keys removal when stopping an AP.
> 
> For example, the optimization option will always be used for cfg80211
> drivers since cfg80211 shall always remove stations and keys when
> stopping an AP (in order to support cases where the AP is disabled
> without the knowledge of wpa_supplicant/hostapd).

Is that the case with all cfg80211 versions through the history? I think
we want to enable this in general, so it sounds acceptable to follow
this justification, but I'd like to make sure it understood if there
are some older kernel versions where this could potentially not work.

> diff --git a/src/ap/hostapd.c b/src/ap/hostapd.c
> index ad1c2d0..5e39438 100644
> --- a/src/ap/hostapd.c
> +++ b/src/ap/hostapd.c
> @@ -1009,6 +1013,10 @@ static int setup_interface(struct hostapd_iface *iface)
>  	struct hostapd_data *hapd = iface->bss[0];
>  	size_t i;
>  
> +	iface->driver_ap_teardown_support =
> +		    !!(iface->drv_flags & WPA_DRIVER_FLAGS_AP_TEARDOWN_SUPPORT);

What's the point in maintaining a separate copy of that bit in the exact
same structure? I'd remove the driver_ap_teardown_support and just use
drv_flags directly.

> +	iface->driver_ap_teardown = 0;

Could you please clarify why driver_ap_teardown is set to 0 here? This
would require at least a comment explaining why that is needed or maybe
even consideration of removing this separate variable completely if it
is not really needed.

-- 
Jouni Malinen                                            PGP id EFC895FA