platform: wifi: drop old wifi data when an interface is renamed

Drop the old wifi data when the interface is renamed, otherwise WEXT
methods would use the old name.

https://bugzilla.gnome.org/show_bug.cgi?id=768433

src/platform/nm-linux-platform.c

@@ -5234,13 +5234,30 @@ static WifiData *
 wifi_get_wifi_data (NMPlatform *platform, int ifindex)
 {
 	NMLinuxPlatformPrivate *priv = NM_LINUX_PLATFORM_GET_PRIVATE (platform);
+	const NMPlatformLink *pllink;
 	WifiData *wifi_data;
 
 	wifi_data = g_hash_table_lookup (priv->wifi_data, GINT_TO_POINTER (ifindex));
-	if (!wifi_data) {
-		const NMPlatformLink *pllink;
-
 	pllink = nm_platform_link_get (platform, ifindex);
+
+	/* @wifi_data contains an interface name which is used for WEXT queries. If
+	 * the interface name changes we should at least replace the name in the
+	 * existing structure; but probably a complete reinitialization is better
+	 * because during the initial creation there can be race conditions while
+	 * the interface is renamed by udev.
+	 */
+	if (wifi_data && pllink) {
+		if (!nm_streq (wifi_utils_get_iface (wifi_data), pllink->name)) {
+			_LOGD ("wifi: interface %s renamed to %s, dropping old data for ifindex %d",
+			       wifi_utils_get_iface (wifi_data),
+			       pllink->name,
+			       ifindex);
+			g_hash_table_remove (priv->wifi_data, GINT_TO_POINTER (ifindex));
+			wifi_data = NULL;
+		}
+	}
+
+	if (!wifi_data) {
 		if (pllink) {
 			if (pllink->type == NM_LINK_TYPE_WIFI)
 				wifi_data = wifi_utils_init (pllink->name, ifindex, TRUE);

src/platform/wifi/wifi-utils.c

@@ -72,6 +72,22 @@ wifi_utils_init (const char *iface, int ifindex, gboolean check_scan)
 	return ret;
 }
 
+int
+wifi_utils_get_ifindex (WifiData *data)
+{
+	g_return_val_if_fail (data != NULL, -1);
+
+	return data->ifindex;
+}
+
+const char *
+wifi_utils_get_iface (WifiData *data)
+{
+	g_return_val_if_fail (data != NULL, NULL);
+
+	return data->iface;
+}
+
 NMDeviceWifiCapabilities
 wifi_utils_get_caps (WifiData *data)
 {

src/platform/wifi/wifi-utils.h

@@ -33,6 +33,10 @@ gboolean wifi_utils_is_wifi (const char *iface);
 
 WifiData *wifi_utils_init (const char *iface, int ifindex, gboolean check_scan);
 
+int wifi_utils_get_ifindex (WifiData *data);
+
+const char *wifi_utils_get_iface (WifiData *data);
+
 void wifi_utils_deinit (WifiData *data);
 
 NMDeviceWifiCapabilities wifi_utils_get_caps (WifiData *data);