device: handle carrier changes for master device differently

For master devices, instead of ignoring loss of carrier entirely,
handle it.

First of all, master devices are now by default ignore-carrier=yes.
That means, without explict user configuration in NetworkManager.conf,
the previous behavior in carrier_changed() does not change.

If the user decides to configure the master device like

    [device-with-carrier]
    match-device=type:bond,type:bridge,type:team
    ignore-carrier=no

then, master device will disconnect on carrier loss like
regular devices.

https://github.com/NetworkManager/NetworkManager/pull/18

Co-authored-by: Thomas Haller <thaller@redhat.com>

2 files changed, 35 insertions, 21 deletions

diff --git a/man/NetworkManager.conf.xml b/man/NetworkManager.conf.xml
index 0dc1b700d9..d8fa1b3b95 100644
--- a/man/NetworkManager.conf.xml
+++ b/man/NetworkManager.conf.xml
@@ -233,7 +233,10 @@ no-auto-default=*
             if specified (See <xref linkend="ignore-carrier"/>).
             Otherwise, it is a list of matches to specify for which device
             carrier should be ignored. See <xref linkend="device-spec"/> for the
-            syntax how to specify a device.
+            syntax how to specify a device. Note that master types like
+            bond, bridge, and team ignore carrier by default. You can however
+            revert that default using the "except:" specifier (or better,
+            use the per-device setting instead of the deprecated setting).
           </para>
         </listitem>
       </varlistentry>
@@ -840,6 +843,10 @@ unmanaged=1
               that NetworkManager will not make use of that information.
             </para>
             <para>
+              Master types like bond, bridge and team ignore carrier by default,
+              while other device types react on carrier changes by default.
+            </para>
+            <para>
               This setting overwrites the deprecated <literal>main.ignore-carrier</literal>
               setting above.
             </para>
diff --git a/src/devices/nm-device.c b/src/devices/nm-device.c
index 866879c2fe..c8b0114afe 100644
--- a/src/devices/nm-device.c
+++ b/src/devices/nm-device.c
@@ -2246,24 +2246,32 @@ carrier_changed (NMDevice *self, gboolean carrier)
 		return;
 
 	if (nm_device_is_master (self)) {
-		/* Bridge/bond/team carrier does not affect its own activation,
-		 * but when carrier comes on, if there are slaves waiting,
-		 * it will restart them.
-		 */
-		if (!carrier)
-			return;
-
-		/* Force master to retry getting ip addresses when carrier
-		 * is restored. */
-		if (priv->state == NM_DEVICE_STATE_ACTIVATED)
-			nm_device_update_dynamic_ip_setup (self);
-		else {
-			if (nm_device_activate_ip4_state_in_wait (self))
-				nm_device_activate_stage3_ip4_start (self);
-			if (nm_device_activate_ip6_state_in_wait (self))
-				nm_device_activate_stage3_ip6_start (self);
+		if (carrier) {
+			/* Force master to retry getting ip addresses when carrier
+			* is restored. */
+			if (priv->state == NM_DEVICE_STATE_ACTIVATED)
+				nm_device_update_dynamic_ip_setup (self);
+			else {
+				if (nm_device_activate_ip4_state_in_wait (self))
+					nm_device_activate_stage3_ip4_start (self);
+				if (nm_device_activate_ip6_state_in_wait (self))
+					nm_device_activate_stage3_ip6_start (self);
+			}
+		} else {
+			 /* Put master device into DISCONNECTED state if there is
+			  * no carrier. This would mean that all slaves are still
+			  * enslaved. This is nessesary to be able to reconnect
+			  * when carrier appears.
+			  */
+			if (priv->state == NM_DEVICE_STATE_DISCONNECTED) {
+				if (   priv->queued_state.id
+				    && priv->queued_state.state >= NM_DEVICE_STATE_PREPARE)
+					queued_state_clear (self);
+			} else {
+				nm_device_queue_state (self, NM_DEVICE_STATE_DISCONNECTED,
+				                       NM_DEVICE_STATE_REASON_CARRIER);
+			}
 		}
-
 		return;
 	} else if (priv->is_enslaved && !carrier) {
 		/* Slaves don't deactivate when they lose carrier; for
@@ -3843,9 +3851,8 @@ nm_device_is_available (NMDevice *self, NMDeviceCheckDevAvailableFlags flags)
 gboolean
 nm_device_ignore_carrier_by_default (NMDevice *self)
 {
-	g_return_val_if_fail (NM_IS_DEVICE (self), FALSE);
-
-	return FALSE;
+	/* master types ignore-carrier by default. */
+	return nm_device_is_master (self);
 }
 
 gboolean