[PATCH 2/3] VHT: Add VHT capabilities checks to IBSS/mesh

Jouni Malinen j at w1.fi
Sun Feb 19 06:11:45 PST 2017

On Tue, Feb 14, 2017 at 02:13:43PM +0900, Masashi Honma wrote:
> diff --git a/wpa_supplicant/wpa_supplicant.c b/wpa_supplicant/wpa_supplicant.c
> @@ -1883,10 +1883,10 @@ static int drv_supports_vht(struct wpa_supplicant *wpa_s,

> -	if (!mode)
> +	if (!mode || mode->vht_capab == 0)
>  		return 0;

This part is fine..

> -	return mode->vht_capab != 0;
> +	return !ieee80211ac_cap_check(mode->vht_capab, ssid->vht_capa);

but this looks problematic. ssid->vht_capa is included only in
CONFIG_VHT_OVERRIDES=y builds, so this would break common builds. In
addition, this breaks number of hwsim test cases (e.g.,
wpas_mesh_open_vht_80p80 ibss_vht_80p80 mesh_open_vht_160) if VHT
overrides are included. It looks like those test cases end up using only
40 MHz channels (HT only?) after this patch.

ssid->vht_capa is cannot really be used without checking
ssid->vht_capa_mask. I'm not completely sure I understand what this
patch is trying to do taken into account ssid->vht_capa is a VHT
override to allow some capabilities to be disabled for testing purposes;
not a normal "enable/disable VHT" parameter.

Jouni Malinen                                            PGP id EFC895FA

More information about the Hostap mailing list