mac80211: add support for wds_bridge hostapd feature

hostapd allows putting WDS (4addr mode) clients into a separate bridge
other than the bridge regular (3addr mode) clients end up in. This is
useful for example giving WDS clients access to several VLANs
(trunking) while regular clients will end up inside a specific VLAN.

Add 'wds_bridge' config parameter for wifi-iface which contains the
name of the bridge. hostapd-mini already supports this feature, so all
needed is to add the UCI wrapping in mac80211.sh.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

package/kernel/mac80211/files/lib/netifd/wireless/mac80211.sh

@@ -62,6 +62,7 @@ drv_mac80211_init_iface_config() {
 	config_add_string 'macaddr:macaddr' ifname
 
 	config_add_boolean wds powersave enable
+	config_add_string wds_bridge
 	config_add_int maxassoc
 	config_add_int max_listen_int
 	config_add_int dtim_period
@@ -340,12 +341,15 @@ mac80211_hostapd_setup_bss() {
 	append hostapd_cfg "$type=$ifname" "$N"
 
 	hostapd_set_bss_options hostapd_cfg "$vif" || return 1
-	json_get_vars wds dtim_period max_listen_int start_disabled
+	json_get_vars wds wds_bridge dtim_period max_listen_int start_disabled
 
 	set_default wds 0
 	set_default start_disabled 0
 
-	[ "$wds" -gt 0 ] && append hostapd_cfg "wds_sta=1" "$N"
+	[ "$wds" -gt 0 ] && {
+		append hostapd_cfg "wds_sta=1" "$N"
+		[ -n "$wds_bridge" ] && append hostapd_cfg "wds_bridge=$wds_bridge" "$N"
+	}
 	[ "$staidx" -gt 0 -o "$start_disabled" -eq 1 ] && append hostapd_cfg "start_disabled=1" "$N"
 
 	cat >> /var/run/hostapd-$phy.conf <<EOF