wifi: set the BridgeIfname supplicant property when needed

When a wifi device is in a bridge, the supplicant must be aware of it,
as a socket must be opened on the bridge to receive packets.

Set the BridgeIfname property of the supplicant Interface object
before starting the association. Note that the property was read-only
in the past and recently [1] became read-write. When using a
supplicant version without the patch, writing the property will return
an InvalidArgs error and NetworkManager will print a warning.

[1] https://w1.fi/cgit/hostap/commit/?id=1c58317f56e312576b6872440f125f794e45f991

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/issues/83

src/devices/wifi/nm-device-wifi.c

@@ -3136,6 +3136,9 @@ act_stage2_config(NMDevice *device, NMDeviceStateReason *out_failure_reason)
     NMSettingWireless *                 s_wireless;
     GError *                            error = NULL;
     guint                               timeout;
+    NMActRequest *                      request;
+    NMActiveConnection *                master_ac;
+    NMDevice *                          master;
 
     nm_clear_g_source(&priv->sup_timeout_id);
     nm_clear_g_source(&priv->link_timeout_id);
@@ -3209,6 +3212,15 @@ act_stage2_config(NMDevice *device, NMDeviceStateReason *out_failure_reason)
         goto out_fail;
     }
 
+    /* Tell the supplicant in which bridge the interface is */
+    if ((request = nm_device_get_act_request(device))
+        && (master_ac = nm_active_connection_get_master(NM_ACTIVE_CONNECTION(request)))
+        && (master = nm_active_connection_get_device(master_ac))
+        && nm_device_get_device_type(master) == NM_DEVICE_TYPE_BRIDGE) {
+        nm_supplicant_interface_set_bridge(priv->sup_iface, nm_device_get_iface(master));
+    } else
+        nm_supplicant_interface_set_bridge(priv->sup_iface, NULL);
+
     nm_supplicant_interface_assoc(priv->sup_iface, config, supplicant_iface_assoc_cb, self);
 
     /* Set up a timeout on the association attempt */

src/supplicant/nm-supplicant-interface.c

@@ -1322,6 +1322,54 @@ nm_supplicant_interface_get_capabilities(NMSupplicantInterface *self)
     return caps;
 }
 
+static void
+set_bridge_cb(GVariant *ret, GError *error, gpointer user_data)
+{
+    NMSupplicantInterface *self;
+    NMLogLevel             level;
+    gs_free const char *   bridge = NULL;
+
+    nm_utils_user_data_unpack(user_data, &self, &bridge);
+
+    if (nm_utils_error_is_cancelled(error))
+        return;
+
+    /* The supplicant supports writing the bridge property since
+     * version 2.10. Before that version, trying to set the property
+     * results in a InvalidArgs error.  Don't log a warning unless we
+     * are trying to set a non-NULL bridge. */
+    if (!error)
+        level = LOGL_DEBUG;
+    else if (bridge == NULL && g_error_matches(error, G_DBUS_ERROR, G_DBUS_ERROR_INVALID_ARGS)) {
+        level = LOGL_DEBUG;
+    } else
+        level = LOGL_WARN;
+
+    _NMLOG(level,
+           "set bridge %s%s%s result: %s",
+           NM_PRINT_FMT_QUOTE_STRING(bridge),
+           error ? error->message : "success");
+}
+
+void
+nm_supplicant_interface_set_bridge(NMSupplicantInterface *self, const char *bridge)
+{
+    NMSupplicantInterfacePrivate *priv = NM_SUPPLICANT_INTERFACE_GET_PRIVATE(self);
+
+    _LOGT("set bridge %s%s%s", NM_PRINT_FMT_QUOTE_STRING(bridge));
+
+    nm_dbus_connection_call_set(priv->dbus_connection,
+                                priv->name_owner->str,
+                                priv->object_path->str,
+                                NM_WPAS_DBUS_IFACE_INTERFACE,
+                                "BridgeIfname",
+                                g_variant_new_string(bridge ?: ""),
+                                DBUS_TIMEOUT_MSEC,
+                                priv->main_cancellable,
+                                set_bridge_cb,
+                                nm_utils_user_data_pack(self, g_strdup(bridge)));
+}
+
 void
 nm_supplicant_interface_set_global_capabilities(NMSupplicantInterface *self, NMSupplCapMask value)
 {

src/supplicant/nm-supplicant-interface.h

@@ -190,4 +190,6 @@ void nm_supplicant_interface_cancel_wps(NMSupplicantInterface *self);
 
 NMSupplicantAuthState nm_supplicant_interface_get_auth_state(NMSupplicantInterface *self);
 
+void nm_supplicant_interface_set_bridge(NMSupplicantInterface *self, const char *bridge);
+
 #endif /* __NM_SUPPLICANT_INTERFACE_H__ */