iked: fix vroute_dbus_dns: System.Error.ENOTCONN

move sd_bus_open_system() to vroute_do_dns(), otherwise
we keep the dbus handle for the lifetime of iked and dbus
calls fail with ENOTCONN.

iked/vroute-netlink.c

@@ -109,15 +109,6 @@ vroute_init(struct iked *env)
 	    NETLINK_ROUTE)) == -1)
 		fatal("%s: failed to create netlink socket", __func__);
 
-#ifdef WITH_SYSTEMD
-	int r;
-	r = sd_bus_open_system(&ivr->ivr_bus);
-	if (r < 0) {
-		log_warn("%s: sd_bus_open_system", __func__);
-		ivr->ivr_bus = NULL;
-	}
-#endif
-
 	TAILQ_INIT(&ivr->ivr_addrs);
 	TAILQ_INIT(&ivr->ivr_dnss);
 	TAILQ_INIT(&ivr->ivr_routes);
@@ -745,12 +736,23 @@ int
 vroute_dodns(struct iked *env, int add, unsigned int ifindex)
 {
 #ifdef WITH_SYSTEMD
+	struct iked_vroute_sc *ivr = env->sc_vroute;
 	const char *destination = "org.freedesktop.resolve1";
 	const char *path = "/org/freedesktop/resolve1";
 	const char *interface = "org.freedesktop.resolve1.Manager";
 	sd_bus_error error = SD_BUS_ERROR_NULL;
 	int ret;
 
+	if (ivr->ivr_bus != NULL) {
+		log_warnx("%s: vr_bus already set, internal error", __func__);
+		return (0);
+	}
+	if (sd_bus_open_system(&ivr->ivr_bus) < 0) {
+		log_warn("%s: sd_bus_open_system failed", __func__);
+		ivr->ivr_bus = NULL;
+		return (0);
+	}
+
 	ret = vroute_dbus_dns(env, ifindex, &error, add,
 	    destination, path, interface);
 	if (ret < 0 && sd_bus_error_has_name(&error,
@@ -780,6 +782,9 @@ vroute_dodns(struct iked *env, int add, unsigned int ifindex)
 		    error.name, error.message);
 		sd_bus_error_free(&error);
 	}
+
+	sd_bus_flush_close_unref(ivr->ivr_bus);
+	ivr->ivr_bus = NULL;
 #endif
 	return (0);
 }