core: prevent multiple attempts to create default wired connection

Scenario:

  - have ethernet connection as unmanaged.
  - create (or have) a suitable profile for the connection.
  - make the device as managed. No default wired connection gets
    created.
  - delete the profile.

Note that NMManager does in manager_device_state_changed():

»···if (NM_IN_SET (new_state,
»···               NM_DEVICE_STATE_UNAVAILABLE,
»···               NM_DEVICE_STATE_DISCONNECTED))
»···»···nm_settings_device_added (priv->settings, device);

that means, when the device the next time goes through
UNAVAILABLE/DISCONNECTED states, we will suddenly create the
default "Wired connection 1" profile.

That doesn't seem right. When a device is suitable to have a
default-wired connection, we should only check once whether to
create it. We should not retry that later. The !no-auto-default
mechanism exists so we can start NetworkManager without a profile for
the device. It doesn't mean that we later one (after previously deciding
not to create a profile), we still create it.

https://bugzilla.redhat.com/show_bug.cgi?id=1687937

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/450

1 files changed, 8 insertions, 1 deletions

diff --git a/src/settings/nm-settings.c b/src/settings/nm-settings.c
index 78361804db..874efbfc2b 100644
--- a/src/settings/nm-settings.c
+++ b/src/settings/nm-settings.c
@@ -70,6 +70,9 @@
 static
 NM_CACHED_QUARK_FCN ("default-wired-connection", _default_wired_connection_quark)
 
+static
+NM_CACHED_QUARK_FCN ("default-wired-connection-blocked", _default_wired_connection_blocked_quark)
+
 /*****************************************************************************/
 
 typedef struct _StorageData {
@@ -3432,9 +3435,13 @@ device_realized (NMDevice *device, GParamSpec *pspec, NMSettings *self)
 	 */
 	if (   !NM_DEVICE_GET_CLASS (device)->new_default_connection
 	    || !nm_device_get_managed (device, FALSE)
-	    || g_object_get_qdata (G_OBJECT (device), _default_wired_connection_quark ()))
+	    || g_object_get_qdata (G_OBJECT (device), _default_wired_connection_blocked_quark ()))
 		return;
 
+	/* we only check once whether to create the auto-default connection. If we reach this point,
+	 * we mark the creation of the default-wired-connection as blocked. */
+	g_object_set_qdata (G_OBJECT (device), _default_wired_connection_blocked_quark (), device);
+
 	if (nm_config_get_no_auto_default_for_device (priv->config, device)) {
 		_LOGT ("auto-default: cannot create auto-default connection for device %s: disabled by \"no-auto-default\"",
 		       nm_device_get_iface (device));