mac80211: Allow preamble configuration

Add a new wireless config parameter short_preamble=0|1 to enable
usage of short preambles. Default is to only allow long preambles
as before.

Even if short_preamble is set to 1 hostapd will take care that
short preambles are disabled as soon as a STA associates that
cannot handle short preambles.

Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>

SVN-Revision: 30539

package/mac80211/files/lib/wifi/mac80211.sh

@@ -16,6 +16,7 @@ mac80211_hostapd_setup_base() {
 	config_get beacon_int "$device" beacon_int
 	config_get basic_rate_list "$device" basic_rate
 	config_get_bool noscan "$device" noscan
+	config_get_bool short_preamble "$device" short_preamble "0"
 
 	hostapd_set_log_options base_cfg "$device"
 
@@ -76,6 +77,8 @@ mac80211_hostapd_setup_base() {
 			brstr="$brstr$brval"
 		done
 	}
+
+	append base_cfg "preamble=$short_preamble" "$N"
 	
 	cat >> "$cfgfile" <<EOF
 ctrl_interface=/var/run/hostapd-$phy