D-Bus: Allow changing an interface bridge via D-Bus

D-Bus clients can call CreateInterface() once and use the resulting
Interface object to connect multiple times to different networks.

However, if the network interface gets added to a bridge, clients
currently have to remove the Interface object and create a new one.

Improve this by supporting the change of the BridgeIfname property of
an existing Interface object.

Signed-off-by: Beniamino Galvani <bgalvani@redhat.com>

src/rsn_supp/tdls.c

@@ -2807,6 +2807,11 @@ int wpa_tdls_init(struct wpa_sm *sm)
 	if (sm == NULL)
 		return -1;
 
+	if (sm->l2_tdls) {
+		l2_packet_deinit(sm->l2_tdls);
+		sm->l2_tdls = NULL;
+	}
+
 	sm->l2_tdls = l2_packet_init(sm->bridge_ifname ? sm->bridge_ifname :
 				     sm->ifname,
 				     sm->own_addr,

wpa_supplicant/dbus/dbus_new.c

@@ -3613,7 +3613,7 @@ static const struct wpa_dbus_property_desc wpas_dbus_interface_properties[] = {
 	},
 	{ "BridgeIfname", WPAS_DBUS_NEW_IFACE_INTERFACE, "s",
 	  wpas_dbus_getter_bridge_ifname,
-	  NULL,
+	  wpas_dbus_setter_bridge_ifname,
 	  NULL
 	},
 	{ "ConfigFile", WPAS_DBUS_NEW_IFACE_INTERFACE, "s",

wpa_supplicant/dbus/dbus_new_handlers.c

@@ -3635,6 +3635,43 @@ dbus_bool_t wpas_dbus_getter_bridge_ifname(
 }
 
 
+dbus_bool_t wpas_dbus_setter_bridge_ifname(
+	const struct wpa_dbus_property_desc *property_desc,
+	DBusMessageIter *iter, DBusError *error, void *user_data)
+{
+	struct wpa_supplicant *wpa_s = user_data;
+	const char *bridge_ifname = NULL;
+	const char *msg;
+	int r;
+
+	if (!wpas_dbus_simple_property_setter(iter, error, DBUS_TYPE_STRING,
+					      &bridge_ifname))
+		return FALSE;
+
+	r = wpa_supplicant_update_bridge_ifname(wpa_s, bridge_ifname);
+	if (r != 0) {
+		switch (r) {
+		case -EINVAL:
+			msg = "invalid interface name";
+			break;
+		case -EBUSY:
+			msg = "interface is busy";
+			break;
+		case -EIO:
+			msg = "socket error";
+			break;
+		default:
+			msg = "unknown error";
+			break;
+		}
+		dbus_set_error_const(error, DBUS_ERROR_FAILED, msg);
+		return FALSE;
+	}
+
+	return TRUE;
+}
+
+
 /**
  * wpas_dbus_getter_config_file - Get interface configuration file path
  * @iter: Pointer to incoming dbus message iter

wpa_supplicant/dbus/dbus_new_handlers.h

@@ -167,6 +167,7 @@ DECLARE_ACCESSOR(wpas_dbus_setter_scan_interval);
 DECLARE_ACCESSOR(wpas_dbus_getter_ifname);
 DECLARE_ACCESSOR(wpas_dbus_getter_driver);
 DECLARE_ACCESSOR(wpas_dbus_getter_bridge_ifname);
+DECLARE_ACCESSOR(wpas_dbus_setter_bridge_ifname);
 DECLARE_ACCESSOR(wpas_dbus_getter_config_file);
 DECLARE_ACCESSOR(wpas_dbus_getter_current_bss);
 DECLARE_ACCESSOR(wpas_dbus_getter_current_network);

wpa_supplicant/wpa_supplicant.c

@@ -4906,6 +4906,65 @@ static void wpa_supplicant_rx_eapol_bridge(void *ctx, const u8 *src_addr,
 }
 
 
+int wpa_supplicant_update_bridge_ifname(struct wpa_supplicant *wpa_s,
+					const char *bridge_ifname)
+{
+	if (wpa_s->wpa_state > WPA_SCANNING)
+		return -EBUSY;
+
+	if (bridge_ifname &&
+	    os_strlen(bridge_ifname) >= sizeof(wpa_s->bridge_ifname))
+		return -EINVAL;
+
+	if (!bridge_ifname)
+		bridge_ifname = "";
+
+	if (os_strcmp(wpa_s->bridge_ifname, bridge_ifname) == 0)
+		return 0;
+
+	if (wpa_s->l2_br) {
+		l2_packet_deinit(wpa_s->l2_br);
+		wpa_s->l2_br = NULL;
+	}
+
+	os_strlcpy(wpa_s->bridge_ifname, bridge_ifname,
+		   sizeof(wpa_s->bridge_ifname));
+
+	if (wpa_s->bridge_ifname[0]) {
+		wpa_dbg(wpa_s, MSG_DEBUG,
+			"Receiving packets from bridge interface '%s'",
+			wpa_s->bridge_ifname);
+		wpa_s->l2_br = l2_packet_init_bridge(
+			wpa_s->bridge_ifname, wpa_s->ifname, wpa_s->own_addr,
+			ETH_P_EAPOL, wpa_supplicant_rx_eapol_bridge, wpa_s, 1);
+		if (!wpa_s->l2_br) {
+			wpa_msg(wpa_s, MSG_ERROR,
+				"Failed to open l2_packet connection for the bridge interface '%s'",
+				wpa_s->bridge_ifname);
+			goto fail;
+		}
+	}
+
+#ifdef CONFIG_TDLS
+	if (!wpa_s->p2p_mgmt && wpa_tdls_init(wpa_s->wpa))
+		goto fail;
+#endif /* CONFIG_TDLS */
+
+	return 0;
+fail:
+	wpa_s->bridge_ifname[0] = 0;
+	if (wpa_s->l2_br) {
+		l2_packet_deinit(wpa_s->l2_br);
+		wpa_s->l2_br = NULL;
+	}
+#ifdef CONFIG_TDLS
+	if (!wpa_s->p2p_mgmt)
+		wpa_tdls_init(wpa_s->wpa);
+#endif /* CONFIG_TDLS */
+	return -EIO;
+}
+
+
 /**
  * wpa_supplicant_driver_init - Initialize driver interface parameters
  * @wpa_s: Pointer to wpa_supplicant data

wpa_supplicant/wpa_supplicant_i.h

@@ -1351,6 +1351,8 @@ int wpa_supplicant_reload_configuration(struct wpa_supplicant *wpa_s);
 const char * wpa_supplicant_state_txt(enum wpa_states state);
 int wpa_supplicant_update_mac_addr(struct wpa_supplicant *wpa_s);
 int wpa_supplicant_driver_init(struct wpa_supplicant *wpa_s);
+int wpa_supplicant_update_bridge_ifname(struct wpa_supplicant *wpa_s,
+					const char *bridge_ifname);
 int wpa_supplicant_set_suites(struct wpa_supplicant *wpa_s,
 			      struct wpa_bss *bss, struct wpa_ssid *ssid,
 			      u8 *wpa_ie, size_t *wpa_ie_len);