bridge: fix reentrant call for bluetooth NAP bridge

Currently NetworkManager fails to establish a NAP bridge because it never gets
out of the stage2.

This is caused because when making the BlueZ callback reentrant we return
NM_ACT_STAGE_RETURN_POSTPONE even after registration has succeeded.

This patch changes registration to a three state automaton instead of a
boolean. This allows distinguishing when we are waiting for registration
to finish and when it is done and therefore ensures that when the stage2
is called again by the callback the result is success so NetworkManager
can proceed to the IP configuration.

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/1181
(cherry picked from commit 8f7e295cbf98ca220fbd13336bb0cdd4d477bd27)

1 files changed, 21 insertions, 10 deletions

diff --git a/src/core/devices/nm-device-bridge.c b/src/core/devices/nm-device-bridge.c
index 4e4c263717..f7af39825d 100644
--- a/src/core/devices/nm-device-bridge.c
+++ b/src/core/devices/nm-device-bridge.c
@@ -22,11 +22,17 @@
 
 /*****************************************************************************/
 
+enum _NMBtCbState {
+    _NM_BT_CB_STATE_NONE    = 0, /* Registration not done    */
+    _NM_BT_CB_STATE_WAIT    = 1, /* Waiting for the callback */
+    _NM_BT_CB_STATE_SUCCESS = 2, /* Callback succeeded       */
+};
+
 struct _NMDeviceBridge {
     NMDevice      parent;
     GCancellable *bt_cancellable;
     bool          vlan_configured : 1;
-    bool          bt_registered : 1;
+    unsigned      bt_cb_state : 2;
 };
 
 struct _NMDeviceBridgeClass {
@@ -76,7 +82,8 @@ check_connection_available(NMDevice                      *device,
         if (!nm_bt_vtable_network_server->is_available(
                 nm_bt_vtable_network_server,
                 bdaddr,
-                (self->bt_cancellable || self->bt_registered) ? device : NULL)) {
+                (self->bt_cancellable || self->bt_cb_state != _NM_BT_CB_STATE_NONE) ? device
+                                                                                    : NULL)) {
             if (bdaddr)
                 nm_utils_error_set(error,
                                    NM_UTILS_ERROR_CONNECTION_AVAILABLE_TEMPORARY,
@@ -835,6 +842,7 @@ _bt_register_bridge_cb(GError *error, gpointer user_data)
         return;
     }
 
+    self->bt_cb_state = _NM_BT_CB_STATE_SUCCESS;
     nm_device_activate_schedule_stage2_device_config(NM_DEVICE(self), FALSE);
 }
 
@@ -846,12 +854,12 @@ _nm_device_bridge_notify_unregister_bt_nap(NMDevice *device, const char *reason)
     _LOGD(LOGD_DEVICE,
           "bluetooth NAP server unregistered from bridge: %s%s",
           reason,
-          self->bt_registered ? "" : " (was no longer registered)");
+          self->bt_cb_state != _NM_BT_CB_STATE_NONE ? "" : " (was no longer registered)");
 
     nm_clear_g_cancellable(&self->bt_cancellable);
 
-    if (self->bt_registered) {
-        self->bt_registered = FALSE;
+    if (self->bt_cb_state != _NM_BT_CB_STATE_NONE) {
+        self->bt_cb_state = _NM_BT_CB_STATE_NONE;
         nm_device_state_changed(device, NM_DEVICE_STATE_FAILED, NM_DEVICE_STATE_REASON_BT_FAILED);
     }
 }
@@ -879,9 +887,12 @@ act_stage2_config(NMDevice *device, NMDeviceStateReason *out_failure_reason)
     if (self->bt_cancellable)
         return NM_ACT_STAGE_RETURN_POSTPONE;
 
-    if (self->bt_registered)
+    if (self->bt_cb_state == _NM_BT_CB_STATE_WAIT)
         return NM_ACT_STAGE_RETURN_POSTPONE;
 
+    if (self->bt_cb_state == _NM_BT_CB_STATE_SUCCESS)
+        return NM_ACT_STAGE_RETURN_SUCCESS;
+
     self->bt_cancellable = g_cancellable_new();
     if (!nm_bt_vtable_network_server->register_bridge(nm_bt_vtable_network_server,
                                                       nm_setting_bluetooth_get_bdaddr(s_bt),
@@ -895,7 +906,7 @@ act_stage2_config(NMDevice *device, NMDeviceStateReason *out_failure_reason)
         return NM_ACT_STAGE_RETURN_FAILURE;
     }
 
-    self->bt_registered = TRUE;
+    self->bt_cb_state = _NM_BT_CB_STATE_WAIT;
     return NM_ACT_STAGE_RETURN_POSTPONE;
 }
 
@@ -906,14 +917,14 @@ deactivate(NMDevice *device)
 
     _LOGD(LOGD_DEVICE,
           "deactivate bridge%s",
-          self->bt_registered ? " (registered as NAP bluetooth device)" : "");
+          self->bt_cb_state != _NM_BT_CB_STATE_NONE ? " (registered as NAP bluetooth device)" : "");
 
     self->vlan_configured = FALSE;
 
     nm_clear_g_cancellable(&self->bt_cancellable);
 
-    if (self->bt_registered) {
-        self->bt_registered = FALSE;
+    if (self->bt_cb_state != _NM_BT_CB_STATE_NONE) {
+        self->bt_cb_state = _NM_BT_CB_STATE_NONE;
         nm_bt_vtable_network_server->unregister_bridge(nm_bt_vtable_network_server, device);
     }
 }