bridge: allow independent IPv4 and IPv6 configuration with no slaves

When no slave is present, dynamic IP configuration (DHCPv4, DHCPv6,
IPv6 autoconf) cannot proceed.  But static and link-local
configuration can.  So if IPv4 requires DHCP but IPv6 is static,
it makes no sense to block IPv6 configuration from proceeding
just because DHCPv4 cannot.

src/nm-device-bridge.c

@@ -46,7 +46,8 @@ G_DEFINE_TYPE (NMDeviceBridge, nm_device_bridge, NM_TYPE_DEVICE_WIRED)
 #define NM_BRIDGE_ERROR (nm_bridge_error_quark ())
 
 typedef struct {
-	gboolean unused;
+	gboolean ip4_waiting;
+	gboolean ip6_waiting;
 } NMDeviceBridgePrivate;
 
 enum {
@@ -85,10 +86,17 @@ device_state_changed (NMDevice *device,
                       NMDeviceState old_state,
                       NMDeviceStateReason reason)
 {
+	NMDeviceBridgePrivate *priv = NM_DEVICE_BRIDGE_GET_PRIVATE (device);
+
 	if (new_state == NM_DEVICE_STATE_UNAVAILABLE) {
 		/* Use NM_DEVICE_STATE_REASON_CARRIER to make sure num retries is reset */
 		nm_device_queue_state (device, NM_DEVICE_STATE_DISCONNECTED, NM_DEVICE_STATE_REASON_CARRIER);
 	}
+
+	if (new_state <= NM_DEVICE_STATE_DISCONNECTED || new_state > NM_DEVICE_STATE_ACTIVATED) {
+		priv->ip4_waiting = FALSE;
+		priv->ip6_waiting = FALSE;
+	}
 }
 
 static void
@@ -363,6 +371,9 @@ act_stage1_prepare (NMDevice *dev, NMDeviceStateReason *reason)
 
 	g_return_val_if_fail (reason != NULL, NM_ACT_STAGE_RETURN_FAILURE);
 
+	NM_DEVICE_BRIDGE_GET_PRIVATE (dev)->ip4_waiting = FALSE;
+	NM_DEVICE_BRIDGE_GET_PRIVATE (dev)->ip6_waiting = FALSE;
+
 	ret = NM_DEVICE_CLASS (nm_device_bridge_parent_class)->act_stage1_prepare (dev, reason);
 	if (ret == NM_ACT_STAGE_RETURN_SUCCESS) {
 		connection = nm_device_get_connection (dev);
@@ -387,6 +398,7 @@ act_stage1_prepare (NMDevice *dev, NMDeviceStateReason *reason)
 static gboolean
 enslave_slave (NMDevice *device, NMDevice *slave, NMConnection *connection)
 {
+	NMDeviceBridgePrivate *priv = NM_DEVICE_BRIDGE_GET_PRIVATE (device);
 	gboolean success;
 	NMSettingBridgePort *s_port;
 	const char *iface = nm_device_get_ip_iface (device);
@@ -410,6 +422,20 @@ enslave_slave (NMDevice *device, NMDevice *slave, NMConnection *connection)
 	nm_log_info (LOGD_DEVICE, "(%s): attached bridge port %s", iface, slave_iface);
 
 	g_object_notify (G_OBJECT (device), NM_DEVICE_BRIDGE_SLAVES);
+
+	/* If waiting for a slave to continue with IP config, start now */
+	if (priv->ip4_waiting) {
+		nm_log_info (LOGD_DEVICE | LOGD_IP4, "(%s): retrying IPv4 config with first slave", iface);
+		priv->ip4_waiting = FALSE;
+		nm_device_activate_stage3_ip4_start (device);
+	}
+
+	if (priv->ip6_waiting) {
+		nm_log_info (LOGD_DEVICE | LOGD_IP6, "(%s): retrying IPv6 config with first slave", iface);
+		priv->ip6_waiting = FALSE;
+		nm_device_activate_stage3_ip6_start (device);
+	}
+
 	return TRUE;
 }
 
@@ -430,6 +456,92 @@ release_slave (NMDevice *device, NMDevice *slave)
 	return success;
 }
 
+static NMActStageReturn
+act_stage3_ip4_config_start (NMDevice *device,
+                             NMIP4Config **out_config,
+                             NMDeviceStateReason *reason)
+{
+	NMDeviceBridgePrivate *priv = NM_DEVICE_BRIDGE_GET_PRIVATE (device);
+	NMActStageReturn ret = NM_ACT_STAGE_RETURN_SUCCESS;
+	NMConnection *connection;
+	NMSettingIP4Config *s_ip4;
+	const char *method = NULL;
+	GSList *slaves;
+
+	priv->ip4_waiting = FALSE;
+
+	slaves = nm_device_master_get_slaves (device);
+	if (slaves == NULL) {
+		connection = nm_device_get_connection (device);
+		g_assert (connection);
+
+		s_ip4 = nm_connection_get_setting_ip4_config (connection);
+		if (s_ip4)
+			method = nm_setting_ip4_config_get_method (s_ip4);
+
+		if (g_strcmp0 (method, NM_SETTING_IP4_CONFIG_METHOD_AUTO) == 0)
+			priv->ip4_waiting = TRUE;
+	}
+	g_slist_free (slaves);
+
+	if (priv->ip4_waiting) {
+		ret = NM_ACT_STAGE_RETURN_WAIT;
+		nm_log_info (LOGD_DEVICE | LOGD_IP4, "(%s): IPv4 config waiting until slaves are present",
+					 nm_device_get_ip_iface (device));
+	} else {
+		/* We have slaves; proceed with normal IPv4 configuration */
+		ret = NM_DEVICE_CLASS (nm_device_bridge_parent_class)->act_stage3_ip4_config_start (device, out_config, reason);
+	}
+
+	return ret;
+}
+
+static NMActStageReturn
+act_stage3_ip6_config_start (NMDevice *device,
+                             NMIP6Config **out_config,
+                             NMDeviceStateReason *reason)
+{
+	NMDeviceBridgePrivate *priv = NM_DEVICE_BRIDGE_GET_PRIVATE (device);
+	NMActStageReturn ret = NM_ACT_STAGE_RETURN_SUCCESS;
+	NMConnection *connection;
+	NMSettingIP6Config *s_ip6;
+	const char *method = NULL;
+	GSList *slaves;
+
+	priv->ip6_waiting = FALSE;
+
+	slaves = nm_device_master_get_slaves (device);
+	if (slaves == NULL) {
+		connection = nm_device_get_connection (device);
+		g_assert (connection);
+
+		s_ip6 = nm_connection_get_setting_ip6_config (connection);
+		if (s_ip6)
+			method = nm_setting_ip6_config_get_method (s_ip6);
+
+		/* SLAAC, DHCP, and Link-Local depend on connectivity (and thus slaves)
+		 * to complete addressing.  SLAAC and DHCP obviously need a peer to
+		 * provide a prefix, while Link-Local must perform DAD on the local link.
+		 */
+		if (   !g_strcmp0 (method, NM_SETTING_IP6_CONFIG_METHOD_AUTO)
+		    || !g_strcmp0 (method, NM_SETTING_IP6_CONFIG_METHOD_DHCP)
+		    || !g_strcmp0 (method, NM_SETTING_IP6_CONFIG_METHOD_LINK_LOCAL))
+			priv->ip6_waiting = TRUE;
+	}
+	g_slist_free (slaves);
+
+	if (priv->ip6_waiting) {
+		ret = NM_ACT_STAGE_RETURN_WAIT;
+		nm_log_info (LOGD_DEVICE | LOGD_IP6, "(%s): IPv6 config waiting until slaves are present",
+					 nm_device_get_ip_iface (device));
+	} else {
+		/* We have slaves; proceed with normal IPv6 configuration */
+		ret = NM_DEVICE_CLASS (nm_device_bridge_parent_class)->act_stage3_ip6_config_start (device, out_config, reason);
+	}
+
+	return ret;
+}
+
 /******************************************************************/
 
 NMDevice *
@@ -527,6 +639,8 @@ nm_device_bridge_class_init (NMDeviceBridgeClass *klass)
 	parent_class->connection_match_config = connection_match_config;
 
 	parent_class->act_stage1_prepare = act_stage1_prepare;
+	parent_class->act_stage3_ip4_config_start = act_stage3_ip4_config_start;
+	parent_class->act_stage3_ip6_config_start = act_stage3_ip6_config_start;
 	parent_class->enslave_slave = enslave_slave;
 	parent_class->release_slave = release_slave;