vlan: Ignore multiple NEWLINK messages

hostapd receives NEWLINK messages multiple times and thus does
configuration of the the vlan interface multiple times.

This is not required and leads to the following during cleanup in
test pmksa_cache_preauth_vlan_used:
 1. run-test.py does: brctl delif brvlan1 wlan3.1
 2. hostapd processes NEWLINK and does: brctl addif brvlan1 wlan3.1
 3. run-test.py does: brctl delbr brvlan1
    -> fails as wlan3.1 is still in the bridge

This patch fixes this by ignoring repeated NEWLINK messages.

Signed-off-by: Michael Braun <michael-dev@fami-braun.de>

src/ap/ap_config.h

@@ -114,6 +114,7 @@ struct hostapd_vlan {
 	struct hostapd_vlan *next;
 	int vlan_id; /* VLAN ID or -1 (VLAN_ID_WILDCARD) for wildcard entry */
 	char ifname[IFNAMSIZ + 1];
+	int configured;
 	int dynamic_vlan;
 #ifdef CONFIG_FULL_DYNAMIC_VLAN
 

src/ap/vlan_init.c

@@ -485,7 +485,8 @@ static void vlan_newlink(char *ifname, struct hostapd_data *hapd)
 	wpa_printf(MSG_DEBUG, "VLAN: vlan_newlink(%s)", ifname);
 
 	while (vlan) {
-		if (os_strcmp(ifname, vlan->ifname) == 0) {
+		if (os_strcmp(ifname, vlan->ifname) == 0 && !vlan->configured) {
+			vlan->configured = 1;
 
 			if (hapd->conf->vlan_bridge[0]) {
 				os_snprintf(br_name, sizeof(br_name), "%s%d",