device: wait for valid MAC before making ethernet devices available

In certain situations, ethernet links first appear with a zero MAC
address and then the MAC changes some time later. Currently NM does
not deal correctly with this scenario since it initializes wrong
@initial_hwaddr and @permanent_hwaddr on the device and tries to
immediately activate it.

To fix this, initialize the device's addresses only when the MAC
becomes valid and make the device available only at that point.

3 files changed, 45 insertions, 5 deletions

diff --git a/src/devices/nm-device-ethernet.c b/src/devices/nm-device-ethernet.c
index c35d472f81..e341cc730a 100644
--- a/src/devices/nm-device-ethernet.c
+++ b/src/devices/nm-device-ethernet.c
@@ -1607,10 +1607,44 @@ link_changed (NMDevice *device, NMPlatformLink *info)
 {
 	NMDeviceEthernet *self = NM_DEVICE_ETHERNET (device);
 	NMDeviceEthernetPrivate *priv = NM_DEVICE_ETHERNET_GET_PRIVATE (self);
+	static const guint8 zero_hwaddr[ETH_ALEN];
+	const guint8 *hwaddr;
+	gsize hwaddrlen = 0;
 
 	NM_DEVICE_CLASS (nm_device_ethernet_parent_class)->link_changed (device, info);
 	if (!priv->subchan1 && info->initialized)
 		_update_s390_subchannels (self);
+
+	if (!nm_device_get_initial_hw_address (device)) {
+		hwaddr = nm_platform_link_get_address (NM_PLATFORM_GET,
+		                                       nm_device_get_ifindex (self),
+		                                       &hwaddrlen);
+		if (!nm_utils_hwaddr_matches (hwaddr, hwaddrlen, zero_hwaddr, ETH_ALEN)) {
+			_LOGD (LOGD_DEVICE, "device got a valid hw address");
+			nm_device_update_hw_address (self);
+			nm_device_update_initial_hw_address (self);
+			if (nm_device_get_state (device) == NM_DEVICE_STATE_UNAVAILABLE) {
+				/*
+				 * If the device is UNAVAILABLE, any previous try to
+				 * bring it up probably has failed because of the
+				 * invalid hardware address; try again.
+				 */
+				nm_device_bring_up (self, TRUE, NULL);
+				nm_device_queue_recheck_available (device,
+				                                   NM_DEVICE_STATE_REASON_NONE,
+				                                   NM_DEVICE_STATE_REASON_NONE);
+			}
+		}
+	}
+}
+
+static gboolean
+is_available (NMDevice *device, NMDeviceCheckDevAvailableFlags flags)
+{
+	if (!NM_DEVICE_CLASS (nm_device_ethernet_parent_class)->is_available (device, flags))
+		return FALSE;
+
+	return !!nm_device_get_initial_hw_address (device);
 }
 
 static void
@@ -1711,6 +1745,7 @@ nm_device_ethernet_class_init (NMDeviceEthernetClass *klass)
 	parent_class->update_connection = update_connection;
 	parent_class->carrier_changed = carrier_changed;
 	parent_class->link_changed = link_changed;
+	parent_class->is_available = is_available;
 
 	parent_class->state_changed = device_state_changed;
 
diff --git a/src/devices/nm-device.c b/src/devices/nm-device.c
index ca7866bb5d..a4b611b5f9 100644
--- a/src/devices/nm-device.c
+++ b/src/devices/nm-device.c
@@ -402,9 +402,6 @@ static void _set_state_full (NMDevice *self,
                              NMDeviceStateReason reason,
                              gboolean quitting);
 
-static void nm_device_update_hw_address (NMDevice *self);
-static void nm_device_update_initial_hw_address (NMDevice *self);
-
 static gboolean queued_ip4_config_change (gpointer user_data);
 static gboolean queued_ip6_config_change (gpointer user_data);
 
@@ -9860,19 +9857,24 @@ nm_device_get_hw_address (NMDevice *self)
 	return priv->hw_addr_len ? priv->hw_addr : NULL;
 }
 
-static void
+void
 nm_device_update_hw_address (NMDevice *self)
 {
 	NMDevicePrivate *priv = NM_DEVICE_GET_PRIVATE (self);
 	int ifindex = nm_device_get_ifindex (self);
 	const guint8 *hwaddr;
 	gsize hwaddrlen = 0;
+	static const guint8 zero_hwaddr[ETH_ALEN];
 
 	if (ifindex <= 0)
 		return;
 
 	hwaddr = nm_platform_link_get_address (NM_PLATFORM_GET, ifindex, &hwaddrlen);
 
+	if (   priv->type == NM_DEVICE_TYPE_ETHERNET
+	    && nm_utils_hwaddr_matches (hwaddr, hwaddrlen, zero_hwaddr, sizeof (zero_hwaddr)))
+		hwaddrlen = 0;
+
 	if (hwaddrlen) {
 		priv->hw_addr_len = hwaddrlen;
 		if (!priv->hw_addr || !nm_utils_hwaddr_matches (priv->hw_addr, -1, hwaddr, hwaddrlen)) {
@@ -9894,7 +9896,7 @@ nm_device_update_hw_address (NMDevice *self)
 	}
 }
 
-static void
+void
 nm_device_update_initial_hw_address (NMDevice *self)
 {
 	NMDevicePrivate *priv = NM_DEVICE_GET_PRIVATE (self);
diff --git a/src/devices/nm-device.h b/src/devices/nm-device.h
index 3ad900f385..8c864e6ff4 100644
--- a/src/devices/nm-device.h
+++ b/src/devices/nm-device.h
@@ -567,6 +567,9 @@ void nm_device_reapply_settings_immediately (NMDevice *self);
 void nm_device_update_firewall_zone (NMDevice *self);
 void nm_device_update_metered (NMDevice *self);
 
+void nm_device_update_hw_address (NMDevice *self);
+void nm_device_update_initial_hw_address (NMDevice *self);
+
 G_END_DECLS
 
 #endif	/* NM_DEVICE_H */