[PATCH v2 19/42] vpn: Check if disconnect is implemented before calling in stop_vpn()

Check if the disconnect() is implemented for the vpn_driver before
attempting to call it when stopping a VPN. Also cleanup the code a bit.
Amends changes made in ffec305c1c93301534144774fffebb25fb9c6c7a
---
 vpn/plugins/vpn.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/vpn/plugins/vpn.c b/vpn/plugins/vpn.c
index 8f04ceb6..047808b6 100644
--- a/vpn/plugins/vpn.c
+++ b/vpn/plugins/vpn.c
@@ -76,6 +76,7 @@ static int stop_vpn(struct vpn_provider *provider)
 {
 	struct vpn_data *data = vpn_provider_get_data(provider);
 	struct vpn_driver_data *vpn_driver_data;
+	const struct vpn_driver *vpn_driver = NULL;
 	const char *name;
 	struct ifreq ifr;
 	int fd, err;
@@ -88,16 +89,19 @@ static int stop_vpn(struct vpn_provider *provider)
 		return -EINVAL;
 
 	vpn_driver_data = g_hash_table_lookup(driver_hash, name);
+	if (vpn_driver_data)
+		vpn_driver = vpn_driver_data->vpn_driver;
 
-	if (vpn_driver_data && vpn_driver_data->vpn_driver &&
-			vpn_driver_data->vpn_driver->flags & VPN_FLAG_NO_TUN) {
+	if (vpn_driver && vpn_driver->flags & VPN_FLAG_NO_TUN) {
 		/*
 		 * Disconnect only VPNs with daemon, otherwise in error return
 		 * there is a double free with vpn_died() or the failure state
 		 * is overridden by changes made by disconnect to state.
 		 */
-		if (!(vpn_driver_data->vpn_driver->flags & VPN_FLAG_NO_DAEMON))
-			vpn_driver_data->vpn_driver->disconnect(data->provider);
+		if (!(vpn_driver->flags & VPN_FLAG_NO_DAEMON) &&
+							vpn_driver->disconnect)
+			vpn_driver->disconnect(data->provider);
+
 		return 0;
 	}
 
-- 
2.39.5