vpn: support option to preserve previous routing information on VPN config update

On openvpn restart, the VPN helper script is invoked without full routing information.
Thus, the routes will be dropped because the helper script cannot provide them
on update.

Add an option "preserve-route" which tells NetworkManager to preserve
and reuse the previous configuration.

https://bugzilla.redhat.com/show_bug.cgi?id=1231338
https://bugzilla.gnome.org/show_bug.cgi?id=750873

3 files changed, 38 insertions, 2 deletions

diff --git a/libnm-core/nm-vpn-dbus-interface.h b/libnm-core/nm-vpn-dbus-interface.h
index 9226458d30..3295a1aeaf 100644
--- a/libnm-core/nm-vpn-dbus-interface.h
+++ b/libnm-core/nm-vpn-dbus-interface.h
@@ -242,6 +242,9 @@ typedef enum {
  */
 #define NM_VPN_PLUGIN_IP4_CONFIG_ROUTES      "routes"
 
+/* whether the previous IP4 routing configuration should be preserved. */
+#define NM_VPN_PLUGIN_IP4_CONFIG_PRESERVE_ROUTES "preserve-routes"
+
 /* boolean: prevent this VPN connection from ever getting the default route */
 #define NM_VPN_PLUGIN_IP4_CONFIG_NEVER_DEFAULT "never-default"
 
@@ -293,6 +296,9 @@ typedef enum {
  */
 #define NM_VPN_PLUGIN_IP6_CONFIG_ROUTES      "routes"
 
+/* whether the previous IP6 routing configuration should be preserved. */
+#define NM_VPN_PLUGIN_IP6_CONFIG_PRESERVE_ROUTES "preserve-routes"
+
 /* boolean: prevent this VPN connection from ever getting the default route */
 #define NM_VPN_PLUGIN_IP6_CONFIG_NEVER_DEFAULT "never-default"
 
diff --git a/shared/nm-utils/nm-vpn-plugin-macros.h b/shared/nm-utils/nm-vpn-plugin-macros.h
index d685934cc1..c85ef17a72 100644
--- a/shared/nm-utils/nm-vpn-plugin-macros.h
+++ b/shared/nm-utils/nm-vpn-plugin-macros.h
@@ -39,5 +39,19 @@ nm_utils_syslog_to_str (int syslog_level)
 	return "<error>";
 }
 
+/*****************************************************************************/
+
+/* possibly missing defines from newer libnm API. */
+
+#ifndef NM_VPN_PLUGIN_IP4_CONFIG_PRESERVE_ROUTES
+#define NM_VPN_PLUGIN_IP4_CONFIG_PRESERVE_ROUTES "preserve-routes"
+#endif
+
+#ifndef NM_VPN_PLUGIN_IP6_CONFIG_PRESERVE_ROUTES
+#define NM_VPN_PLUGIN_IP6_CONFIG_PRESERVE_ROUTES "preserve-routes"
+#endif
+
+/*****************************************************************************/
+
 #endif /* __NM_VPN_PLUGIN_MACROS_H__ */
 
diff --git a/src/vpn-manager/nm-vpn-connection.c b/src/vpn-manager/nm-vpn-connection.c
index bdbd4e6f6f..53789093cb 100644
--- a/src/vpn-manager/nm-vpn-connection.c
+++ b/src/vpn-manager/nm-vpn-connection.c
@@ -1340,6 +1340,7 @@ nm_vpn_connection_ip4_config_get (NMVpnConnection *self, GVariant *dict)
 	const char *str;
 	GVariant *v;
 	gboolean b;
+	guint i, n;
 
 	g_return_if_fail (dict && g_variant_is_of_type (dict, G_VARIANT_TYPE_VARDICT));
 
@@ -1426,7 +1427,14 @@ nm_vpn_connection_ip4_config_get (NMVpnConnection *self, GVariant *dict)
 
 	route_metric = nm_vpn_connection_get_ip4_route_metric (self);
 
-	if (g_variant_lookup (dict, NM_VPN_PLUGIN_IP4_CONFIG_ROUTES, "aau", &iter)) {
+	if (   g_variant_lookup (dict, NM_VPN_PLUGIN_IP4_CONFIG_PRESERVE_ROUTES, "b", &b)
+	    && b) {
+		if (priv->ip4_config) {
+			n = nm_ip4_config_get_num_routes (priv->ip4_config);
+			for (i = 0; i < n; i++)
+				nm_ip4_config_add_route (config, nm_ip4_config_get_route (priv->ip4_config, i));
+		}
+	} else if (g_variant_lookup (dict, NM_VPN_PLUGIN_IP4_CONFIG_ROUTES, "aau", &iter)) {
 		while (g_variant_iter_next (iter, "@au", &v)) {
 			NMPlatformIP4Route route = { 0, };
 
@@ -1492,6 +1500,7 @@ nm_vpn_connection_ip6_config_get (NMVpnConnection *self, GVariant *dict)
 	const char *str;
 	GVariant *v;
 	gboolean b;
+	guint i, n;
 
 	g_return_if_fail (dict && g_variant_is_of_type (dict, G_VARIANT_TYPE_VARDICT));
 
@@ -1568,7 +1577,14 @@ nm_vpn_connection_ip6_config_get (NMVpnConnection *self, GVariant *dict)
 
 	route_metric = nm_vpn_connection_get_ip6_route_metric (self);
 
-	if (g_variant_lookup (dict, NM_VPN_PLUGIN_IP6_CONFIG_ROUTES, "a(ayuayu)", &iter)) {
+	if (   g_variant_lookup (dict, NM_VPN_PLUGIN_IP6_CONFIG_PRESERVE_ROUTES, "b", &b)
+	    && b) {
+		if (priv->ip6_config) {
+			n = nm_ip6_config_get_num_routes (priv->ip6_config);
+			for (i = 0; i < n; i++)
+				nm_ip6_config_add_route (config, nm_ip6_config_get_route (priv->ip6_config, i));
+		}
+	} else if (g_variant_lookup (dict, NM_VPN_PLUGIN_IP6_CONFIG_ROUTES, "a(ayuayu)", &iter)) {
 		GVariant *dest, *next_hop;
 		guint32 prefix, metric;