device: merge branch 'bg/parent-mtu-rh1723690-part1'

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/merge_requests/273
(cherry picked from commit facfc94744)
(cherry picked from commit 188911ae7d)

src/devices/nm-device-ethernet.c

@@ -1374,13 +1374,15 @@ act_stage3_ip_config_start (NMDevice *device,
 }
 
 static guint32
-get_configured_mtu (NMDevice *device, NMDeviceMtuSource *out_source)
+get_configured_mtu (NMDevice *device,
+                    NMDeviceMtuSource *out_source,
+                    gboolean *out_force)
 {
 	/* MTU only set for plain ethernet */
 	if (NM_DEVICE_ETHERNET_GET_PRIVATE ((NMDeviceEthernet *) device)->ppp_manager)
 		return 0;
 
-	return nm_device_get_configured_mtu_for_wired (device, out_source);
+	return nm_device_get_configured_mtu_for_wired (device, out_source, out_force);
 }
 
 static void

src/devices/nm-device-infiniband.c

@@ -117,7 +117,9 @@ act_stage1_prepare (NMDevice *device, NMDeviceStateReason *out_failure_reason)
 }
 
 static guint32
-get_configured_mtu (NMDevice *device, NMDeviceMtuSource *out_source)
+get_configured_mtu (NMDevice *device,
+                    NMDeviceMtuSource *out_source,
+                    gboolean *out_force)
 {
 	return nm_device_get_configured_mtu_from_connection (device,
 	                                                     NM_TYPE_SETTING_INFINIBAND,

src/devices/nm-device-ip-tunnel.c

@@ -854,7 +854,9 @@ create_and_realize (NMDevice *device,
 }
 
 static guint32
-get_configured_mtu (NMDevice *device, NMDeviceMtuSource *out_source)
+get_configured_mtu (NMDevice *device,
+                    NMDeviceMtuSource *out_source,
+                    gboolean *out_force)
 {
 	return nm_device_get_configured_mtu_from_connection (device,
 	                                                     NM_TYPE_SETTING_IP_TUNNEL,

src/devices/nm-device-macsec.c

@@ -67,6 +67,7 @@ NM_GOBJECT_PROPERTIES_DEFINE (NMDeviceMacsec,
 typedef struct {
 	NMPlatformLnkMacsec props;
 	gulong parent_state_id;
+	gulong parent_mtu_id;
 	Supplicant supplicant;
 	guint supplicant_timeout_id;
 	NMActRequestGetSecretsCallId *macsec_secrets_id;
@@ -114,6 +115,17 @@ parent_state_changed (NMDevice *parent,
 	nm_device_set_unmanaged_by_flags (NM_DEVICE (self), NM_UNMANAGED_PARENT, !nm_device_get_managed (parent, FALSE), reason);
 }
 
+static void
+parent_mtu_maybe_changed (NMDevice *parent,
+                          GParamSpec *pspec,
+                          gpointer user_data)
+{
+	/* the MTU of a MACsec device is limited by the parent's MTU.
+	 *
+	 * When the parent's MTU changes, try to re-set the MTU. */
+	nm_device_commit_mtu (user_data);
+}
+
 static void
 parent_changed_notify (NMDevice *device,
                        int old_ifindex,
@@ -134,12 +146,16 @@ parent_changed_notify (NMDevice *device,
 	 *  because NMDevice's dispose() will unset the parent, which in turn calls
 	 *  parent_changed_notify(). */
 	nm_clear_g_signal_handler (old_parent, &priv->parent_state_id);
+	nm_clear_g_signal_handler (old_parent, &priv->parent_mtu_id);
 
 	if (new_parent) {
 		priv->parent_state_id = g_signal_connect (new_parent,
 		                                          NM_DEVICE_STATE_CHANGED,
 		                                          G_CALLBACK (parent_state_changed),
 		                                          device);
+		priv->parent_mtu_id = g_signal_connect (new_parent, "notify::" NM_DEVICE_MTU,
+		                                        G_CALLBACK (parent_mtu_maybe_changed), device);
+
 
 		/* Set parent-dependent unmanaged flag */
 		nm_device_set_unmanaged_by_flags (device,
@@ -792,11 +808,15 @@ static void
 dispose (GObject *object)
 {
 	NMDeviceMacsec *self = NM_DEVICE_MACSEC (object);
+	NMDeviceMacsecPrivate *priv = NM_DEVICE_MACSEC_GET_PRIVATE (self);
 
 	macsec_secrets_cancel (self);
 	supplicant_interface_release (self);
 
 	G_OBJECT_CLASS (nm_device_macsec_parent_class)->dispose (object);
+
+	nm_assert (priv->parent_state_id == 0);
+	nm_assert (priv->parent_mtu_id == 0);
 }
 
 static const NMDBusInterfaceInfoExtended interface_info_device_macsec = {
@@ -839,6 +859,7 @@ nm_device_macsec_class_init (NMDeviceMacsecClass *klass)
 	device_class->connection_type_supported = NM_SETTING_MACSEC_SETTING_NAME;
 	device_class->connection_type_check_compatible = NM_SETTING_MACSEC_SETTING_NAME;
 	device_class->link_types = NM_DEVICE_DEFINE_LINK_TYPES (NM_LINK_TYPE_MACSEC);
+	device_class->mtu_parent_delta = 32;
 
 	device_class->act_stage2_config = act_stage2_config;
 	device_class->create_and_realize = create_and_realize;
@@ -848,7 +869,7 @@ nm_device_macsec_class_init (NMDeviceMacsecClass *klass)
 	device_class->is_available = is_available;
 	device_class->parent_changed_notify = parent_changed_notify;
 	device_class->state_changed = device_state_changed;
-	device_class->get_configured_mtu = nm_device_get_configured_mtu_for_wired;
+	device_class->get_configured_mtu = nm_device_get_configured_mtu_wired_parent;
 
 	obj_properties[PROP_SCI] =
 	    g_param_spec_uint64 (NM_DEVICE_MACSEC_SCI, "", "",

src/devices/nm-device-macvlan.c

@@ -49,6 +49,7 @@ NM_GOBJECT_PROPERTIES_DEFINE (NMDeviceMacvlan,
 
 typedef struct {
 	gulong parent_state_id;
+	gulong parent_mtu_id;
 	NMPlatformLnkMacvlan props;
 } NMDeviceMacvlanPrivate;
 
@@ -135,6 +136,17 @@ parent_state_changed (NMDevice *parent,
 	nm_device_set_unmanaged_by_flags (NM_DEVICE (self), NM_UNMANAGED_PARENT, !nm_device_get_managed (parent, FALSE), reason);
 }
 
+static void
+parent_mtu_maybe_changed (NMDevice *parent,
+                          GParamSpec *pspec,
+                          gpointer user_data)
+{
+	/* the MTU of a macvlan/macvtap device is limited by the parent's MTU.
+	 *
+	 * When the parent's MTU changes, try to re-set the MTU. */
+	nm_device_commit_mtu (user_data);
+}
+
 static void
 parent_changed_notify (NMDevice *device,
                        int old_ifindex,
@@ -151,12 +163,15 @@ parent_changed_notify (NMDevice *device,
 	 *  because NMDevice's dispose() will unset the parent, which in turn calls
 	 *  parent_changed_notify(). */
 	nm_clear_g_signal_handler (old_parent, &priv->parent_state_id);
+	nm_clear_g_signal_handler (old_parent, &priv->parent_mtu_id);
 
 	if (new_parent) {
 		priv->parent_state_id = g_signal_connect (new_parent,
 		                                          NM_DEVICE_STATE_CHANGED,
 		                                          G_CALLBACK (parent_state_changed),
 		                                          device);
+		priv->parent_mtu_id = g_signal_connect (new_parent, "notify::" NM_DEVICE_MTU,
+		                                        G_CALLBACK (parent_mtu_maybe_changed), device);
 
 		/* Set parent-dependent unmanaged flag */
 		nm_device_set_unmanaged_by_flags (device,
@@ -475,6 +490,17 @@ nm_device_macvlan_init (NMDeviceMacvlan *self)
 {
 }
 
+static void
+dispose (GObject *object)
+{
+	NMDeviceMacvlanPrivate *priv = NM_DEVICE_MACVLAN_GET_PRIVATE (object);
+
+	G_OBJECT_CLASS (nm_device_macvlan_parent_class)->dispose (object);
+
+	nm_assert (priv->parent_state_id == 0);
+	nm_assert (priv->parent_mtu_id == 0);
+}
+
 static const NMDBusInterfaceInfoExtended interface_info_device_macvlan = {
 	.parent = NM_DEFINE_GDBUS_INTERFACE_INFO_INIT (
 		NM_DBUS_INTERFACE_DEVICE_MACVLAN,
@@ -498,6 +524,7 @@ nm_device_macvlan_class_init (NMDeviceMacvlanClass *klass)
 	NMDBusObjectClass *dbus_object_class = NM_DBUS_OBJECT_CLASS (klass);
 	NMDeviceClass *device_class = NM_DEVICE_CLASS (klass);
 
+	object_class->dispose = dispose;
 	object_class->get_property = get_property;
 	object_class->set_property = set_property;
 
@@ -506,13 +533,14 @@ nm_device_macvlan_class_init (NMDeviceMacvlanClass *klass)
 	device_class->connection_type_supported = NM_SETTING_MACVLAN_SETTING_NAME;
 	device_class->connection_type_check_compatible = NM_SETTING_MACVLAN_SETTING_NAME;
 	device_class->link_types = NM_DEVICE_DEFINE_LINK_TYPES (NM_LINK_TYPE_MACVLAN, NM_LINK_TYPE_MACVTAP);
+	device_class->mtu_parent_delta = 0;
 
 	device_class->act_stage1_prepare = act_stage1_prepare;
 	device_class->check_connection_compatible = check_connection_compatible;
 	device_class->complete_connection = complete_connection;
 	device_class->create_and_realize = create_and_realize;
 	device_class->get_generic_capabilities = get_generic_capabilities;
-	device_class->get_configured_mtu = nm_device_get_configured_mtu_for_wired;
+	device_class->get_configured_mtu = nm_device_get_configured_mtu_wired_parent;
 	device_class->is_available = is_available;
 	device_class->link_changed = link_changed;
 	device_class->parent_changed_notify = parent_changed_notify;

src/devices/nm-device-private.h

@@ -175,7 +175,11 @@ guint32 nm_device_get_configured_mtu_from_connection (NMDevice *device,
                                                       GType setting_type,
                                                       NMDeviceMtuSource *out_source);
 
-guint32 nm_device_get_configured_mtu_for_wired (NMDevice *self, NMDeviceMtuSource *out_source);
+guint32 nm_device_get_configured_mtu_for_wired (NMDevice *self, NMDeviceMtuSource *out_source, gboolean *out_force);
+
+guint32 nm_device_get_configured_mtu_wired_parent (NMDevice *self,
+                                                   NMDeviceMtuSource *out_source,
+                                                   gboolean *out_force);
 
 void nm_device_commit_mtu (NMDevice *self);
 

src/devices/nm-device-vlan.c

@@ -523,26 +523,6 @@ act_stage1_prepare (NMDevice *device, NMDeviceStateReason *out_failure_reason)
 	return ret;
 }
 
-static guint32
-get_configured_mtu (NMDevice *self, NMDeviceMtuSource *out_source)
-{
-	guint32 mtu = 0;
-	int ifindex;
-
-	mtu = nm_device_get_configured_mtu_for_wired (self, out_source);
-	if (*out_source != NM_DEVICE_MTU_SOURCE_NONE)
-		return mtu;
-
-	/* Inherit the MTU from parent device, if any */
-	ifindex = nm_device_parent_get_ifindex (self);
-	if (ifindex > 0) {
-		mtu = nm_platform_link_get_mtu (nm_device_get_platform (NM_DEVICE (self)), ifindex);
-		*out_source = NM_DEVICE_MTU_SOURCE_PARENT;
-	}
-
-	return mtu;
-}
-
 /*****************************************************************************/
 
 static void
@@ -598,13 +578,14 @@ nm_device_vlan_class_init (NMDeviceVlanClass *klass)
 	device_class->connection_type_supported = NM_SETTING_VLAN_SETTING_NAME;
 	device_class->connection_type_check_compatible = NM_SETTING_VLAN_SETTING_NAME;
 	device_class->link_types = NM_DEVICE_DEFINE_LINK_TYPES (NM_LINK_TYPE_VLAN);
+	device_class->mtu_parent_delta = 0; /* VLANs can have the same MTU of parent */
 
 	device_class->create_and_realize = create_and_realize;
 	device_class->link_changed = link_changed;
 	device_class->unrealize_notify = unrealize_notify;
 	device_class->get_generic_capabilities = get_generic_capabilities;
 	device_class->act_stage1_prepare = act_stage1_prepare;
-	device_class->get_configured_mtu = get_configured_mtu;
+	device_class->get_configured_mtu = nm_device_get_configured_mtu_wired_parent;
 	device_class->is_available = is_available;
 	device_class->parent_changed_notify = parent_changed_notify;
 

src/devices/nm-device-wireguard.c

@@ -1378,7 +1378,7 @@ act_stage3_ip_config_start (NMDevice *device,
 }
 
 static guint32
-get_configured_mtu (NMDevice *device, NMDeviceMtuSource *out_source)
+get_configured_mtu (NMDevice *device, NMDeviceMtuSource *out_source, gboolean *out_force)
 {
 	/* When "MTU" for `wg-quick up` is unset, it calls `ip route get` for
 	 * each configured endpoint, to determine the suitable MTU how to reach

src/devices/nm-device.c

@@ -9068,13 +9068,59 @@ nm_device_get_configured_mtu_from_connection (NMDevice *self,
 }
 
 guint32
-nm_device_get_configured_mtu_for_wired (NMDevice *self, NMDeviceMtuSource *out_source)
+nm_device_get_configured_mtu_for_wired (NMDevice *self,
+                                        NMDeviceMtuSource *out_source,
+                                        gboolean *out_force)
 {
 	return nm_device_get_configured_mtu_from_connection (self,
 	                                                     NM_TYPE_SETTING_WIRED,
 	                                                     out_source);
 }
 
+guint32
+nm_device_get_configured_mtu_wired_parent (NMDevice *self,
+                                           NMDeviceMtuSource *out_source,
+                                           gboolean *out_force)
+{
+	guint32 mtu = 0;
+	guint32 parent_mtu = 0;
+	int ifindex;
+
+	ifindex = nm_device_parent_get_ifindex (self);
+	if (ifindex > 0) {
+		parent_mtu = nm_platform_link_get_mtu (nm_device_get_platform (self), ifindex);
+		if (parent_mtu >= NM_DEVICE_GET_CLASS (self)->mtu_parent_delta)
+			parent_mtu -= NM_DEVICE_GET_CLASS (self)->mtu_parent_delta;
+		else
+			parent_mtu = 0;
+	}
+
+	mtu = nm_device_get_configured_mtu_for_wired (self, out_source, NULL);
+
+	if (parent_mtu && mtu > parent_mtu) {
+		/* Trying to set a MTU that is out of range from configuration:
+		 * fall back to the parent MTU and set force flag so that it
+		 * overrides an MTU with higher priority already configured.
+		 */
+		 *out_source = NM_DEVICE_MTU_SOURCE_PARENT;
+		 *out_force = TRUE;
+		 return parent_mtu;
+	}
+
+	if (*out_source != NM_DEVICE_MTU_SOURCE_NONE) {
+		nm_assert (mtu > 0);
+		return mtu;
+	}
+
+	/* Inherit the MTU from parent device, if any */
+	if (parent_mtu) {
+		mtu = parent_mtu;
+		*out_source = NM_DEVICE_MTU_SOURCE_PARENT;
+	}
+
+	return mtu;
+}
+
 /*****************************************************************************/
 
 static void
@@ -9126,15 +9172,34 @@ _commit_mtu (NMDevice *self, const NMIP4Config *config)
 
 	{
 		guint32 mtu = 0;
+		gboolean force = FALSE;
 
-		/* preferably, get the MTU from explicit user-configuration.
+		/* We take the MTU from various sources: (in order of increasing
-		 * Only if that fails, look at the current @config (which contains
+		 * priority) parent link, IP configuration (which contains the
-		 * MTUs from DHCP/PPP) or maybe fallback to a device-specific MTU. */
+		 * MTU from DHCP/PPP), connection profile.
+		 *
+		 * We could just compare it with the platform MTU and apply it
+		 * when different, but this would revert at random times manual
+		 * changes done by the user with the MTU from the connection.
+		 *
+		 * Instead, we remember the source of the currently configured
+		 * MTU and apply the new one only when the new source has a
+		 * higher priority, so that we don't set a MTU from same source
+		 * multiple times. An exception to this is for the PARENT
+		 * source, since we need to keep tracking the parent MTU when it
+		 * changes.
+		 *
+		 * The subclass can set the @force argument to TRUE to signal that the
+		 * returned MTU should be applied even if it has a lower priority. This
+		 * is useful when the value from a lower source should
+		 * preempt the one from higher ones.
+		 */
 
 		if (NM_DEVICE_GET_CLASS (self)->get_configured_mtu)
-			mtu = NM_DEVICE_GET_CLASS (self)->get_configured_mtu (self, &source);
+			mtu = NM_DEVICE_GET_CLASS (self)->get_configured_mtu (self, &source, &force);
 
 		if (   config
+		    && !force
 		    && source < NM_DEVICE_MTU_SOURCE_IP_CONFIG
 		    && nm_ip4_config_get_mtu (config)) {
 			mtu = nm_ip4_config_get_mtu (config);
@@ -9143,14 +9208,16 @@ _commit_mtu (NMDevice *self, const NMIP4Config *config)
 
 		if (mtu != 0) {
 			_LOGT (LOGD_DEVICE,
-			       "mtu: value %u from source '%s' (%u), current source '%s' (%u)",
+			       "mtu: value %u from source '%s' (%u), current source '%s' (%u)%s",
 			       (guint) mtu,
 			       mtu_source_to_str (source), (guint) source,
-			       mtu_source_to_str (priv->mtu_source), (guint) priv->mtu_source);
+			       mtu_source_to_str (priv->mtu_source), (guint) priv->mtu_source,
+			       force ? " (forced)" : "");
 		}
 
 		if (   mtu != 0
-		    && (   source > priv->mtu_source
+		    && (   force
+		        || source > priv->mtu_source
 		        || (priv->mtu_source == NM_DEVICE_MTU_SOURCE_PARENT && source == priv->mtu_source)))
 			mtu_desired = mtu;
 		else {
@@ -14575,6 +14642,7 @@ nm_device_cleanup (NMDevice *self, NMDeviceStateReason reason, CleanupType clean
 	}
 
 	priv->mtu_source = NM_DEVICE_MTU_SOURCE_NONE;
+	priv->ip6_mtu = 0;
 	if (priv->mtu_initial || priv->ip6_mtu_initial) {
 		ifindex = nm_device_get_ip_ifindex (self);
 

src/devices/nm-device.h

@@ -240,6 +240,10 @@ typedef struct _NMDeviceClass {
 
 	const NMLinkType *link_types;
 
+	/* if the device MTU is set based on parent's one, this specifies
+	 * a delta in the MTU allowed value due the encapsulation overhead */
+	guint16 mtu_parent_delta;
+
 	/* Whether the device type is a master-type. This depends purely on the
 	 * type (NMDeviceClass), not the actual device instance. */
 	bool is_master:1;
@@ -330,7 +334,9 @@ typedef struct _NMDeviceClass {
 	                                  NMSettingsConnection *sett_conn,
 	                                  char **specific_object);
 
-	guint32     (*get_configured_mtu) (NMDevice *self, NMDeviceMtuSource *out_source);
+	guint32     (*get_configured_mtu) (NMDevice *self,
+	                                   NMDeviceMtuSource *out_source,
+	                                   gboolean *out_force);
 
 	const char *(*get_auto_ip_config_method) (NMDevice *self, int addr_family);
 

src/devices/wifi/nm-device-iwd.c

@@ -1911,7 +1911,9 @@ out:
 }
 
 static guint32
-get_configured_mtu (NMDevice *device, NMDeviceMtuSource *out_source)
+get_configured_mtu (NMDevice *device,
+                    NMDeviceMtuSource *out_source,
+                    gboolean *out_force)
 {
 	return nm_device_get_configured_mtu_from_connection (device,
 	                                                     NM_TYPE_SETTING_WIRELESS,

src/devices/wifi/nm-device-wifi-p2p.c

@@ -628,7 +628,9 @@ deactivate (NMDevice *device)
 }
 
 static guint32
-get_configured_mtu (NMDevice *device, NMDeviceMtuSource *out_source)
+get_configured_mtu (NMDevice *device,
+                    NMDeviceMtuSource *out_source,
+                    gboolean *out_force)
 {
 	*out_source = NM_DEVICE_MTU_SOURCE_NONE;
 	return 0;

src/devices/wifi/nm-device-wifi.c

@@ -2901,7 +2901,9 @@ act_stage3_ip_config_start (NMDevice *device,
 }
 
 static guint32
-get_configured_mtu (NMDevice *device, NMDeviceMtuSource *out_source)
+get_configured_mtu (NMDevice *device,
+                    NMDeviceMtuSource *out_source,
+                    gboolean *out_force)
 {
 	return nm_device_get_configured_mtu_from_connection (device,
 	                                                     NM_TYPE_SETTING_WIRELESS,

src/devices/wwan/nm-modem.c

@@ -858,7 +858,9 @@ nm_modem_stage3_ip6_config_start (NMModem *self,
 }
 
 guint32
-nm_modem_get_configured_mtu (NMDevice *self, NMDeviceMtuSource *out_source)
+nm_modem_get_configured_mtu (NMDevice *self,
+                             NMDeviceMtuSource *out_source,
+                             gboolean *out_force)
 {
 	NMConnection *connection;
 	NMSetting *setting;

src/devices/wwan/nm-modem.h

@@ -282,6 +282,6 @@ void nm_modem_emit_ip6_config_result (NMModem *self,
 
 const char *nm_modem_ip_type_to_string (NMModemIPType ip_type);
 
-guint32 nm_modem_get_configured_mtu (NMDevice *self, NMDeviceMtuSource *out_source);
+guint32 nm_modem_get_configured_mtu (NMDevice *self, NMDeviceMtuSource *out_source, gboolean *out_force);
 
 #endif /* __NETWORKMANAGER_MODEM_H__ */