device: merge branch 'th/device-mtu-rh1414901'

https://bugzilla.redhat.com/show_bug.cgi?id=1414901

libnm-core/nm-utils.c

@@ -32,6 +32,7 @@
 #include <libintl.h>
 #include <gmodule.h>
 #include <sys/stat.h>
+#include <net/if.h>
 
 #if WITH_JANSSON
 #include <jansson.h>
@@ -3675,36 +3676,41 @@ _nm_utils_generate_mac_address_mask_parse (const char *value,
 gboolean
 nm_utils_is_valid_iface_name (const char *name, GError **error)
 {
-	g_return_val_if_fail (name != NULL, FALSE);
+	int i;
 
-	if (*name == '\0') {
+	g_return_val_if_fail (name, FALSE);
+
+	if (name[0] == '\0') {
 		g_set_error_literal (error, NM_UTILS_ERROR, NM_UTILS_ERROR_UNKNOWN,
 		                     _("interface name is too short"));
 		return FALSE;
 	}
 
-	if (strlen (name) >= 16) {
+	if (   name[0] == '.'
-		g_set_error_literal (error, NM_UTILS_ERROR, NM_UTILS_ERROR_UNKNOWN,
+	    && (   name[1] == '\0'
-		                     _("interface name is longer than 15 characters"));
+	        || (   name[1] == '.'
-		return FALSE;
+	            && name[2] == '\0'))) {
-	}
-
-	if (!strcmp (name, ".") || !strcmp (name, "..")) {
 		g_set_error_literal (error, NM_UTILS_ERROR, NM_UTILS_ERROR_UNKNOWN,
 		                     _("interface name is reserved"));
 		return FALSE;
 	}
 
-	while (*name) {
+	for (i = 0; i < IFNAMSIZ; i++) {
-		if (*name == '/' || g_ascii_isspace (*name)) {
+		char ch = name[i];
+
+		if (ch == '\0')
+			return TRUE;
+		if (   NM_IN_SET (ch, '/', ':')
+		    || g_ascii_isspace (ch)) {
 			g_set_error_literal (error, NM_UTILS_ERROR, NM_UTILS_ERROR_UNKNOWN,
 			                     _("interface name contains an invalid character"));
 			return FALSE;
 		}
-		name++;
 	}
 
-	return TRUE;
+	g_set_error_literal (error, NM_UTILS_ERROR, NM_UTILS_ERROR_UNKNOWN,
+	                     _("interface name is longer than 15 characters"));
+	return FALSE;
 }
 
 /**

src/devices/nm-device-private.h

@@ -118,6 +118,8 @@ gint64 nm_device_get_configured_mtu_from_connection_default (NMDevice *self,
 
 guint32 nm_device_get_configured_mtu_for_wired (NMDevice *self, gboolean *out_is_user_config);
 
+void nm_device_commit_mtu (NMDevice *self);
+
 /*****************************************************************************/
 
 #define NM_DEVICE_CLASS_DECLARE_TYPES(klass, conn_type, ...) \

src/devices/nm-device-vlan.c

@@ -51,6 +51,7 @@ NM_GOBJECT_PROPERTIES_DEFINE (NMDeviceVlan,
 typedef struct {
 	gulong parent_state_id;
 	gulong parent_hwaddr_id;
+	gulong parent_mtu_id;
 	guint vlan_id;
 } NMDeviceVlanPrivate;
 
@@ -85,6 +86,17 @@ 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 VLAN 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_hwaddr_maybe_changed (NMDevice *parent,
                              GParamSpec *pspec,
@@ -143,6 +155,7 @@ parent_changed_notify (NMDevice *device,
 	 *  parent_changed_notify(). */
 	nm_clear_g_signal_handler (old_parent, &priv->parent_state_id);
 	nm_clear_g_signal_handler (old_parent, &priv->parent_hwaddr_id);
+	nm_clear_g_signal_handler (old_parent, &priv->parent_mtu_id);
 
 	if (new_parent) {
 		priv->parent_state_id = g_signal_connect (new_parent,
@@ -154,6 +167,10 @@ parent_changed_notify (NMDevice *device,
 		                                           G_CALLBACK (parent_hwaddr_maybe_changed), device);
 		parent_hwaddr_maybe_changed (new_parent, NULL, self);
 
+		priv->parent_mtu_id = g_signal_connect (new_parent, "notify::" NM_DEVICE_MTU,
+		                                        G_CALLBACK (parent_mtu_maybe_changed), device);
+		parent_mtu_maybe_changed (new_parent, NULL, self);
+
 		/* Set parent-dependent unmanaged flag */
 		nm_device_set_unmanaged_by_flags (device,
 		                                  NM_UNMANAGED_PARENT,
@@ -482,8 +499,10 @@ act_stage1_prepare (NMDevice *device, NMDeviceStateReason *out_failure_reason)
 
 	/* Change MAC address to parent's one if needed */
 	parent_device = nm_device_parent_get_device (device);
-	if (parent_device)
+	if (parent_device) {
 		parent_hwaddr_maybe_changed (parent_device, NULL, device);
+		parent_mtu_maybe_changed (parent_device, NULL, device);
+	}
 
 	s_vlan = (NMSettingVlan *) nm_device_get_applied_setting (device, NM_TYPE_SETTING_VLAN);
 	if (s_vlan) {

src/devices/nm-device.c

@@ -72,6 +72,7 @@
 #include "nm-arping-manager.h"
 #include "nm-connectivity.h"
 #include "nm-dbus-interface.h"
+#include "nm-device-vlan.h"
 
 #include "nm-device-logging.h"
 _LOG_DECLARE_SELF (NMDevice);
@@ -550,6 +551,7 @@ static void realize_start_setup (NMDevice *self,
                                  const char *assume_state_connection_uuid,
                                  gboolean set_nm_owned,
                                  NMUnmanFlagOp unmanaged_user_explicit);
+static void _set_mtu (NMDevice *self, guint32 mtu);
 static void _commit_mtu (NMDevice *self, const NMIP4Config *config);
 static void dhcp_schedule_restart (NMDevice *self, int addr_family, const char *reason);
 static void _cancel_activation (NMDevice *self);
@@ -851,26 +853,29 @@ nm_device_ipv4_sysctl_set (NMDevice *self, const char *property, const char *val
 	NMPlatform *platform = nm_device_get_platform (self);
 	gs_free char *value_to_free = NULL;
 	const char *value_to_set;
+	char buf[NM_UTILS_SYSCTL_IP_CONF_PATH_BUFSIZE];
 
 	if (value) {
 		value_to_set = value;
 	} else {
 		/* Set to a default value when we've got a NULL @value. */
 		value_to_free = nm_platform_sysctl_get (platform,
-		                                        NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip4_property_path ("default", property)));
+		                                        NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_sysctl_ip_conf_path (AF_INET, buf, "default", property)));
 		value_to_set = value_to_free;
 	}
 
 	return nm_platform_sysctl_set (platform,
-	                               NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip4_property_path (nm_device_get_ip_iface (self), property)),
+	                               NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_sysctl_ip_conf_path (AF_INET, buf, nm_device_get_ip_iface (self), property)),
 	                               value_to_set);
 }
 
 static guint32
 nm_device_ipv4_sysctl_get_uint32 (NMDevice *self, const char *property, guint32 fallback)
 {
+	char buf[NM_UTILS_SYSCTL_IP_CONF_PATH_BUFSIZE];
+
 	return nm_platform_sysctl_get_int_checked (nm_device_get_platform (self),
-	                                           NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip4_property_path (nm_device_get_ip_iface (self), property)),
+	                                           NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_sysctl_ip_conf_path (AF_INET, buf, nm_device_get_ip_iface (self), property)),
 	                                           10,
 	                                           0,
 	                                           G_MAXUINT32,
@@ -880,14 +885,18 @@ nm_device_ipv4_sysctl_get_uint32 (NMDevice *self, const char *property, guint32
 gboolean
 nm_device_ipv6_sysctl_set (NMDevice *self, const char *property, const char *value)
 {
-	return nm_platform_sysctl_set (nm_device_get_platform (self), NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip6_property_path (nm_device_get_ip_iface (self), property)), value);
+	char buf[NM_UTILS_SYSCTL_IP_CONF_PATH_BUFSIZE];
+
+	return nm_platform_sysctl_set (nm_device_get_platform (self), NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_sysctl_ip_conf_path (AF_INET6, buf, nm_device_get_ip_iface (self), property)), value);
 }
 
 static guint32
 nm_device_ipv6_sysctl_get_uint32 (NMDevice *self, const char *property, guint32 fallback)
 {
+	char buf[NM_UTILS_SYSCTL_IP_CONF_PATH_BUFSIZE];
+
 	return nm_platform_sysctl_get_int_checked (nm_device_get_platform (self),
-	                                           NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip6_property_path (nm_device_get_ip_iface (self), property)),
+	                                           NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_sysctl_ip_conf_path (AF_INET6, buf, nm_device_get_ip_iface (self), property)),
 	                                           10,
 	                                           0,
 	                                           G_MAXUINT32,
@@ -2672,10 +2681,7 @@ device_link_changed (NMDevice *self)
 		_notify (self, PROP_DRIVER);
 	}
 
-	if (priv->mtu != info.mtu) {
+	_set_mtu (self, info.mtu);
-		priv->mtu = info.mtu;
-		_notify (self, PROP_MTU);
-	}
 
 	if (ifindex == nm_device_get_ip_ifindex (self))
 		_stats_update_counters_from_pllink (self, &info);
@@ -3242,7 +3248,6 @@ realize_start_setup (NMDevice *self,
 	NMDeviceCapabilities capabilities = 0;
 	NMConfig *config;
 	guint real_rate;
-	guint32 mtu;
 
 	/* plink is a NMPlatformLink type, however, we require it to come from the platform
 	 * cache (where else would it come from?). */
@@ -3271,10 +3276,7 @@ realize_start_setup (NMDevice *self,
 	priv->mtu_initial = 0;
 	priv->ip6_mtu_initial = 0;
 	priv->ip6_mtu = 0;
-	if (priv->mtu) {
+	_set_mtu (self, 0);
-		priv->mtu = 0;
-		_notify (self, PROP_MTU);
-	}
 
 	_assume_state_set (self, assume_state_guess_assume, assume_state_connection_uuid);
 
@@ -3295,11 +3297,9 @@ realize_start_setup (NMDevice *self,
 		if (nm_platform_link_is_software (nm_device_get_platform (self), priv->ifindex))
 			capabilities |= NM_DEVICE_CAP_IS_SOFTWARE;
 
-		mtu = nm_platform_link_get_mtu (nm_device_get_platform (self), priv->ifindex);
+		_set_mtu (self,
-		if (priv->mtu != mtu) {
+		          nm_platform_link_get_mtu (nm_device_get_platform (self),
-			priv->mtu = mtu;
+		                                    priv->ifindex));
-			_notify (self, PROP_MTU);
-		}
 
 		nm_platform_link_get_driver_info (nm_device_get_platform (self),
 		                                  priv->ifindex,
@@ -3524,10 +3524,7 @@ nm_device_unrealize (NMDevice *self, gboolean remove_resources, GError **error)
 	if (nm_clear_g_free (&priv->ip_iface))
 		_notify (self, PROP_IP_IFACE);
 
-	if (priv->mtu != 0) {
+	_set_mtu (self, 0);
-		priv->mtu = 0;
-		_notify (self, PROP_MTU);
-	}
 
 	if (priv->driver_version) {
 		g_clear_pointer (&priv->driver_version, g_free);
@@ -7211,6 +7208,26 @@ nm_device_get_configured_mtu_for_wired (NMDevice *self, gboolean *out_is_user_co
 
 /*****************************************************************************/
 
+static void
+_set_mtu (NMDevice *self, guint32 mtu)
+{
+	NMDevicePrivate *priv = NM_DEVICE_GET_PRIVATE (self);
+
+	if (priv->mtu == mtu)
+		return;
+
+	priv->mtu = mtu;
+	_notify (self, PROP_MTU);
+
+	if (priv->master) {
+		/* changing the MTU of a slave, might require the master to reset
+		 * it's MTU. Note that the master usually cannot set a MTU larger
+		 * then the slave's. Hence, when the slave increases the MTU,
+		 * master might want to retry setting the MTU. */
+		nm_device_commit_mtu (priv->master);
+	}
+}
+
 static void
 _commit_mtu (NMDevice *self, const NMIP4Config *config)
 {
@@ -7230,8 +7247,7 @@ _commit_mtu (NMDevice *self, const NMIP4Config *config)
 		return;
 
 	if (nm_device_sys_iface_state_is_external_or_assume (self)) {
-		/* for assumed connections we don't tamper with the MTU. This is
+		/* for assumed connections we don't tamper with the MTU. */
-		 * a bug and supposed to be fixed by the unmanaged/assumed rework. */
 		return;
 	}
 
@@ -7331,6 +7347,7 @@ _commit_mtu (NMDevice *self, const NMIP4Config *config)
 	})
 	if (   (mtu_desired && mtu_desired != mtu_plat)
 	    || (ip6_mtu && ip6_mtu != _IP6_MTU_SYS ())) {
+		gboolean anticipated_failure = FALSE;
 
 		if (!priv->mtu_initial && !priv->ip6_mtu_initial) {
 			/* before touching any of the MTU paramters, record the
@@ -7340,19 +7357,52 @@ _commit_mtu (NMDevice *self, const NMIP4Config *config)
 		}
 
 		if (mtu_desired && mtu_desired != mtu_plat) {
-			nm_platform_link_set_mtu (nm_device_get_platform (self), ifindex, mtu_desired);
+			if (nm_platform_link_set_mtu (nm_device_get_platform (self), ifindex, mtu_desired) == NM_PLATFORM_ERROR_CANT_SET_MTU) {
+				anticipated_failure = TRUE;
+				_LOGW (LOGD_DEVICE, "mtu: failure to set MTU. %s",
+				       NM_IS_DEVICE_VLAN (self)
+				         ? "Is the parent's MTU size large enough?"
+				         : (!c_list_is_empty (&priv->slaves)
+				              ? "Are the MTU sizes of the slaves large enough?"
+				              : "Did you configure the MTU correctly?"));
+			}
 			priv->carrier_wait_until_ms = nm_utils_get_monotonic_timestamp_ms () + CARRIER_WAIT_TIME_AFTER_MTU_MS;
 		}
 
 		if (ip6_mtu && ip6_mtu != _IP6_MTU_SYS ()) {
-			nm_device_ipv6_sysctl_set (self, "mtu",
+			if (!nm_device_ipv6_sysctl_set (self, "mtu",
-			                           nm_sprintf_buf (sbuf, "%u", (unsigned) ip6_mtu));
+			                                nm_sprintf_buf (sbuf, "%u", (unsigned) ip6_mtu))) {
+				int errsv = errno;
+
+				_NMLOG (anticipated_failure && errsv == EINVAL ? LOGL_DEBUG : LOGL_WARN,
+				        LOGD_DEVICE,
+				        "mtu: failure to set IPv6 MTU%s",
+				        anticipated_failure && errsv == EINVAL
+				           ? ": Is the underlying MTU value successfully set?"
+				           : "");
+			}
 			priv->carrier_wait_until_ms = nm_utils_get_monotonic_timestamp_ms () + CARRIER_WAIT_TIME_AFTER_MTU_MS;
 		}
 	}
 #undef _IP6_MTU_SYS
 }
 
+void
+nm_device_commit_mtu (NMDevice *self)
+{
+	NMDeviceState state;
+
+	g_return_if_fail (NM_IS_DEVICE (self));
+
+	state = nm_device_get_state (self);
+	if (   state >= NM_DEVICE_STATE_CONFIG
+	    && state < NM_DEVICE_STATE_DEACTIVATING) {
+		_LOGT (LOGD_DEVICE, "mtu: commit-mtu...");
+		_commit_mtu (self, NM_DEVICE_GET_PRIVATE (self)->ip4_config);
+	} else
+		_LOGT (LOGD_DEVICE, "mtu: commit-mtu... skip due to state %s", nm_device_state_to_str (state));
+}
+
 static void
 ndisc_config_changed (NMNDisc *ndisc, const NMNDiscData *rdata, guint changed_int, NMDevice *self)
 {
@@ -7654,7 +7704,9 @@ save_ip6_properties (NMDevice *self)
 	g_hash_table_remove_all (priv->ip6_saved_properties);
 
 	for (i = 0; i < G_N_ELEMENTS (ip6_properties_to_save); i++) {
-		value = nm_platform_sysctl_get (nm_device_get_platform (self), NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip6_property_path (ifname, ip6_properties_to_save[i])));
+		char buf[NM_UTILS_SYSCTL_IP_CONF_PATH_BUFSIZE];
+
+		value = nm_platform_sysctl_get (nm_device_get_platform (self), NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_sysctl_ip_conf_path (AF_INET6, buf, ifname, ip6_properties_to_save[i])));
 		if (value) {
 			g_hash_table_insert (priv->ip6_saved_properties,
 			                     (char *) ip6_properties_to_save[i],
@@ -7714,9 +7766,11 @@ set_nm_ipv6ll (NMDevice *self, gboolean enable)
 		}
 
 		if (enable) {
+			char buf[NM_UTILS_SYSCTL_IP_CONF_PATH_BUFSIZE];
+
 			/* Bounce IPv6 to ensure the kernel stops IPv6LL address generation */
 			value = nm_platform_sysctl_get (nm_device_get_platform (self),
-			                                NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip6_property_path (nm_device_get_ip_iface (self), "disable_ipv6")));
+			                                NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_sysctl_ip_conf_path (AF_INET6, buf, nm_device_get_ip_iface (self), "disable_ipv6")));
 			if (g_strcmp0 (value, "0") == 0)
 				nm_device_ipv6_sysctl_set (self, "disable_ipv6", "1");
 			g_free (value);

src/ndisc/nm-lndp-ndisc.c

@@ -531,8 +531,10 @@ start (NMNDisc *ndisc)
 static inline int
 ipv6_sysctl_get (NMPlatform *platform, const char *ifname, const char *property, int min, int max, int defval)
 {
+	char buf[NM_UTILS_SYSCTL_IP_CONF_PATH_BUFSIZE];
+
 	return (int) nm_platform_sysctl_get_int_checked (platform,
-	                                                 NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip6_property_path (ifname, property)),
+	                                                 NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_sysctl_ip_conf_path (AF_INET6, buf, ifname, property)),
 	                                                 10,
 	                                                 min,
 	                                                 max,

src/nm-core-utils.c

@@ -2525,55 +2525,88 @@ nm_utils_monotonic_timestamp_as_boottime (gint64 timestamp, gint64 timestamp_ns_
 #define IPV6_PROPERTY_DIR "/proc/sys/net/ipv6/conf/"
 #define IPV4_PROPERTY_DIR "/proc/sys/net/ipv4/conf/"
 G_STATIC_ASSERT (sizeof (IPV4_PROPERTY_DIR) == sizeof (IPV6_PROPERTY_DIR));
+G_STATIC_ASSERT (NM_STRLEN (IPV6_PROPERTY_DIR) + IFNAMSIZ + 60 == NM_UTILS_SYSCTL_IP_CONF_PATH_BUFSIZE);
 
-static const char *
+/**
-_get_property_path (const char *ifname,
+ * nm_utils_sysctl_ip_conf_path:
-                    const char *property,
+ * @addr_family: either AF_INET or AF_INET6.
-                    gboolean ipv6)
+ * @buf: the output buffer where to write the path. It
+ *   must be at least NM_UTILS_SYSCTL_IP_CONF_PATH_BUFSIZE bytes
+ *   long.
+ * @ifname: an interface name
+ * @property: a property name
+ *
+ * Returns: the path to IPv6 property @property on @ifname. Note that
+ * this returns the input argument @buf.
+ */
+const char *
+nm_utils_sysctl_ip_conf_path (int addr_family, char *buf, const char *ifname, const char *property)
 {
-	static char path[sizeof (IPV6_PROPERTY_DIR) + IFNAMSIZ + 32];
 	int len;
 
-	ifname = NM_ASSERT_VALID_PATH_COMPONENT (ifname);
+	nm_assert (buf);
+	nm_assert_addr_family (addr_family);
+
+	g_assert (nm_utils_is_valid_iface_name (ifname, NULL));
 	property = NM_ASSERT_VALID_PATH_COMPONENT (property);
 
-	len = g_snprintf (path,
+	len = g_snprintf (buf,
-	                  sizeof (path),
+	                  NM_UTILS_SYSCTL_IP_CONF_PATH_BUFSIZE,
 	                  "%s%s/%s",
-	                  ipv6 ? IPV6_PROPERTY_DIR : IPV4_PROPERTY_DIR,
+	                  addr_family == AF_INET6 ? IPV6_PROPERTY_DIR : IPV4_PROPERTY_DIR,
 	                  ifname,
 	                  property);
-	g_assert (len < sizeof (path) - 1);
+	g_assert (len < NM_UTILS_SYSCTL_IP_CONF_PATH_BUFSIZE - 1);
-
+	return buf;
-	return path;
 }
 
-/**
+gboolean
- * nm_utils_ip6_property_path:
+nm_utils_sysctl_ip_conf_is_path (int addr_family, const char *path, const char *ifname, const char *property)
- * @ifname: an interface name
- * @property: a property name
- *
- * Returns the path to IPv6 property @property on @ifname. Note that
- * this uses a static buffer.
- */
-const char *
-nm_utils_ip6_property_path (const char *ifname, const char *property)
 {
-	return _get_property_path (ifname, property, TRUE);
+	g_return_val_if_fail (path, FALSE);
-}
+	NM_ASSERT_VALID_PATH_COMPONENT (property);
+	g_assert (!ifname || nm_utils_is_valid_iface_name (ifname, NULL));
 
-/**
+	if (addr_family == AF_INET) {
- * nm_utils_ip4_property_path:
+		if (!g_str_has_prefix (path, IPV4_PROPERTY_DIR))
- * @ifname: an interface name
+			return FALSE;
- * @property: a property name
+		path += NM_STRLEN (IPV4_PROPERTY_DIR);
- *
+	} else if (addr_family == AF_INET6) {
- * Returns the path to IPv4 property @property on @ifname. Note that
+		if (!g_str_has_prefix (path, IPV6_PROPERTY_DIR))
- * this uses a static buffer.
+			return FALSE;
- */
+		path += NM_STRLEN (IPV6_PROPERTY_DIR);
-const char *
+	} else
-nm_utils_ip4_property_path (const char *ifname, const char *property)
+		g_return_val_if_reached (FALSE);
-{
+
-	return _get_property_path (ifname, property, FALSE);
+	if (ifname) {
+		if (!g_str_has_prefix (path, ifname))
+			return FALSE;
+		path += strlen (ifname);
+		if (path[0] != '/')
+			return FALSE;
+		path++;
+	} else {
+		const char *slash;
+		char buf[IFNAMSIZ];
+		gsize l;
+
+		slash = strchr (path, '/');
+		if (!slash)
+			return FALSE;
+		l = slash - path;
+		if (l >= IFNAMSIZ)
+			return FALSE;
+		memcpy (buf, path, l);
+		buf[l] = '\0';
+		if (!nm_utils_is_valid_iface_name (buf, NULL))
+			return FALSE;
+		path = slash + 1;
+	}
+
+	if (!nm_streq (path, property))
+		return FALSE;
+
+	return TRUE;
 }
 
 gboolean

src/nm-core-utils.h

@@ -248,8 +248,12 @@ gint64 nm_utils_monotonic_timestamp_as_boottime (gint64 timestamp, gint64 timest
 
 gboolean    nm_utils_is_valid_path_component (const char *name);
 const char *NM_ASSERT_VALID_PATH_COMPONENT (const char *name);
-const char *nm_utils_ip6_property_path (const char *ifname, const char *property);
+
-const char *nm_utils_ip4_property_path (const char *ifname, const char *property);
+#define NM_UTILS_SYSCTL_IP_CONF_PATH_BUFSIZE 100
+
+const char *nm_utils_sysctl_ip_conf_path (int addr_family, char *buf, const char *ifname, const char *property);
+
+gboolean nm_utils_sysctl_ip_conf_is_path (int addr_family, const char *path, const char *ifname, const char *property);
 
 gboolean nm_utils_is_specific_hostname (const char *name);
 

src/nm-iface-helper.c

@@ -222,9 +222,10 @@ ndisc_config_changed (NMNDisc *ndisc, const NMNDiscData *rdata, guint changed_in
 
 	if (changed & NM_NDISC_CONFIG_MTU) {
 		char val[16];
+		char sysctl_path_buf[NM_UTILS_SYSCTL_IP_CONF_PATH_BUFSIZE];
 
 		g_snprintf (val, sizeof (val), "%d", rdata->mtu);
-		nm_platform_sysctl_set (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip6_property_path (global_opt.ifname, "mtu")), val);
+		nm_platform_sysctl_set (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_sysctl_ip_conf_path (AF_INET6, sysctl_path_buf, global_opt.ifname, "mtu")), val);
 	}
 
 	nm_ip6_config_merge (existing, ndisc_config, NM_IP_CONFIG_MERGE_DEFAULT, 0);
@@ -344,6 +345,7 @@ main (int argc, char *argv[])
 	gconstpointer tmp;
 	gs_free NMUtilsIPv6IfaceId *iid = NULL;
 	guint sd_id;
+	char sysctl_path_buf[NM_UTILS_SYSCTL_IP_CONF_PATH_BUFSIZE];
 
 	nm_g_type_init ();
 
@@ -448,7 +450,7 @@ main (int argc, char *argv[])
 	}
 
 	if (global_opt.dhcp4_address) {
-		nm_platform_sysctl_set (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip4_property_path (global_opt.ifname, "promote_secondaries")), "1");
+		nm_platform_sysctl_set (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_sysctl_ip_conf_path (AF_INET, sysctl_path_buf, global_opt.ifname, "promote_secondaries")), "1");
 
 		dhcp4_client = nm_dhcp_manager_start_ip4 (nm_dhcp_manager_get (),
 		                                          nm_platform_get_multi_idx (NM_PLATFORM_GET),
@@ -497,10 +499,10 @@ main (int argc, char *argv[])
 		if (iid)
 			nm_ndisc_set_iid (ndisc, *iid);
 
-		nm_platform_sysctl_set (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip6_property_path (global_opt.ifname, "accept_ra")), "1");
+		nm_platform_sysctl_set (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_sysctl_ip_conf_path (AF_INET6, sysctl_path_buf, global_opt.ifname, "accept_ra")), "1");
-		nm_platform_sysctl_set (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip6_property_path (global_opt.ifname, "accept_ra_defrtr")), "0");
+		nm_platform_sysctl_set (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_sysctl_ip_conf_path (AF_INET6, sysctl_path_buf, global_opt.ifname, "accept_ra_defrtr")), "0");
-		nm_platform_sysctl_set (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip6_property_path (global_opt.ifname, "accept_ra_pinfo")), "0");
+		nm_platform_sysctl_set (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_sysctl_ip_conf_path (AF_INET6, sysctl_path_buf, global_opt.ifname, "accept_ra_pinfo")), "0");
-		nm_platform_sysctl_set (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_ip6_property_path (global_opt.ifname, "accept_ra_rtr_pref")), "0");
+		nm_platform_sysctl_set (NM_PLATFORM_GET, NMP_SYSCTL_PATHID_ABSOLUTE (nm_utils_sysctl_ip_conf_path (AF_INET6, sysctl_path_buf, global_opt.ifname, "accept_ra_rtr_pref")), "0");
 
 		g_signal_connect (NM_PLATFORM_GET,
 		                  NM_PLATFORM_SIGNAL_IP6_ADDRESS_CHANGED,

src/platform/nm-fake-platform.c

@@ -585,7 +585,7 @@ link_set_address (NMPlatform *platform, int ifindex, gconstpointer addr, size_t
 	return NM_PLATFORM_ERROR_SUCCESS;
 }
 
-static gboolean
+static NMPlatformError
 link_set_mtu (NMPlatform *platform, int ifindex, guint32 mtu)
 {
 	NMFakePlatformLink *device = link_get (platform, ifindex);
@@ -593,13 +593,13 @@ link_set_mtu (NMPlatform *platform, int ifindex, guint32 mtu)
 
 	if (!device) {
 		_LOGE ("failure changing link: netlink error (No such device)");
-		return FALSE;
+		return NM_PLATFORM_ERROR_EXISTS;
 	}
 
 	obj_tmp = nmp_object_clone (device->obj, FALSE);
 	obj_tmp->link.mtu = mtu;
 	link_set_obj (platform, device, obj_tmp);
-	return TRUE;
+	return NM_PLATFORM_ERROR_SUCCESS;
 }
 
 static gboolean

src/platform/nm-linux-platform.c

@@ -206,6 +206,21 @@ typedef enum {
 	INFINIBAND_ACTION_DELETE_CHILD,
 } InfinibandAction;
 
+typedef enum {
+	CHANGE_LINK_TYPE_UNSPEC,
+	CHANGE_LINK_TYPE_SET_MTU,
+	CHANGE_LINK_TYPE_SET_ADDRESS,
+} ChangeLinkType;
+
+typedef struct {
+	union {
+		struct {
+			gconstpointer address;
+			gsize length;
+		} set_address;
+	};
+} ChangeLinkData;
+
 enum {
 	DELAYED_ACTION_IDX_REFRESH_ALL_LINKS,
 	DELAYED_ACTION_IDX_REFRESH_ALL_IP4_ADDRESSES,
@@ -2934,7 +2949,7 @@ sysctl_set (NMPlatform *platform, const char *pathid, int dirfd, const char *pat
 	nm_auto_pop_netns NMPNetns *netns = NULL;
 	int fd, tries;
 	gssize nwrote;
-	gsize len;
+	gssize len;
 	char *actual;
 	gs_free char *actual_free = NULL;
 	int errsv;
@@ -2989,6 +3004,7 @@ sysctl_set (NMPlatform *platform, const char *pathid, int dirfd, const char *pat
 	 * about to write.
 	 */
 	len = strlen (value) + 1;
+	nm_assert (len > 0);
 	if (len > 512)
 		actual = actual_free = g_malloc (len + 1);
 	else
@@ -3010,8 +3026,19 @@ sysctl_set (NMPlatform *platform, const char *pathid, int dirfd, const char *pat
 			break;
 		}
 	}
-	if (nwrote == -1 && errsv != EEXIST) {
+	if (nwrote == -1) {
-		_LOGE ("sysctl: failed to set '%s' to '%s': (%d) %s",
+		NMLogLevel level = LOGL_ERR;
+
+		if (errsv == EEXIST) {
+			level = LOGL_DEBUG;
+		} else if (   errsv == EINVAL
+		           && nm_utils_sysctl_ip_conf_is_path (AF_INET6, path, NULL, "mtu")) {
+			/* setting the MTU can fail under regular conditions. Suppress
+			 * logging a warning. */
+			level = LOGL_DEBUG;
+		}
+
+		_NMLOG (level, "sysctl: failed to set '%s' to '%s': (%d) %s",
 		        path, value, errsv, strerror (errsv));
 	} else if (nwrote < len - 1) {
 		_LOGE ("sysctl: failed to set '%s' to '%s' after three attempts",
@@ -4410,25 +4437,38 @@ do_delete_object (NMPlatform *platform, const NMPObject *obj_id, struct nl_msg *
 	return success;
 }
 
-static WaitForNlResponseResult
+static NMPlatformError
-do_change_link_request (NMPlatform *platform,
+do_change_link (NMPlatform *platform,
+                ChangeLinkType change_link_type,
                 int ifindex,
-                        struct nl_msg *nlmsg)
+                struct nl_msg *nlmsg,
+                const ChangeLinkData *data)
 {
 	nm_auto_pop_netns NMPNetns *netns = NULL;
-	WaitForNlResponseResult seq_result = WAIT_FOR_NL_RESPONSE_RESULT_UNKNOWN;
 	int nle;
+	WaitForNlResponseResult seq_result = WAIT_FOR_NL_RESPONSE_RESULT_UNKNOWN;
+	char s_buf[256];
+	NMPlatformError result = NM_PLATFORM_ERROR_SUCCESS;
+	NMLogLevel log_level = LOGL_DEBUG;
+	const char *log_result = "failure";
+	const char *log_detail = "";
+	gs_free char *log_detail_free = NULL;
+	const NMPObject *obj_cache;
 
-	if (!nm_platform_netns_push (platform, &netns))
+	if (!nm_platform_netns_push (platform, &netns)) {
-		return WAIT_FOR_NL_RESPONSE_RESULT_UNKNOWN;
+		log_level = LOGL_ERR;
+		log_detail = ", failure to change network namespace";
+		goto out;
+	}
 
 retry:
 	nle = _nl_send_nlmsg (platform, nlmsg, &seq_result, DELAYED_ACTION_RESPONSE_TYPE_VOID, NULL);
 	if (nle < 0) {
-		_LOGE ("do-change-link[%d]: failure sending netlink request \"%s\" (%d)",
+		log_level = LOGL_ERR;
-		       ifindex,
+		log_detail_free = g_strdup_printf (", failure sending netlink request: %s (%d)",
 		                                   nl_geterror (nle), -nle);
-		return WAIT_FOR_NL_RESPONSE_RESULT_UNKNOWN;
+		log_detail = log_detail_free;
+		goto out;
 	}
 
 	/* always refetch the link after changing it. There seems to be issues
@@ -4444,18 +4484,6 @@ retry:
 		nlmsg_hdr (nlmsg)->nlmsg_type = RTM_SETLINK;
 		goto retry;
 	}
-	return seq_result;
-}
-
-static NMPlatformError
-do_change_link_result (NMPlatform *platform,
-                       int ifindex,
-                       WaitForNlResponseResult seq_result)
-{
-	char s_buf[256];
-	NMPlatformError result = NM_PLATFORM_ERROR_SUCCESS;
-	NMLogLevel log_level = LOGL_DEBUG;
-	const char *log_result = "failure", *log_detail = "";
 
 	if (seq_result == WAIT_FOR_NL_RESPONSE_RESULT_RESPONSE_OK) {
 		log_result = "success";
@@ -4464,6 +4492,20 @@ do_change_link_result (NMPlatform *platform,
 	} else if (NM_IN_SET (-((int) seq_result), ESRCH, ENOENT)) {
 		log_detail = ", firmware not found";
 		result = NM_PLATFORM_ERROR_NO_FIRMWARE;
+	} else if (   NM_IN_SET (-((int) seq_result), ERANGE)
+	           && change_link_type == CHANGE_LINK_TYPE_SET_MTU) {
+		log_detail = ", setting MTU to requested size is not possible";
+		result = NM_PLATFORM_ERROR_CANT_SET_MTU;
+	} else if (   NM_IN_SET (-((int) seq_result), ENFILE)
+	           && change_link_type == CHANGE_LINK_TYPE_SET_ADDRESS
+	           && (obj_cache = nmp_cache_lookup_link (nm_platform_get_cache (platform), ifindex))
+	           && obj_cache->link.addr.len == data->set_address.length
+	           && memcmp (obj_cache->link.addr.data, data->set_address.address, data->set_address.length) == 0) {
+		/* workaround ENFILE which may be wrongly returned (bgo #770456).
+		 * If the MAC address is as expected, assume success? */
+		log_result = "success";
+		log_detail = " (assume success changing address)";
+		result = NM_PLATFORM_ERROR_SUCCESS;
 	} else if (NM_IN_SET (-((int) seq_result), ENODEV)) {
 		log_level = LOGL_DEBUG;
 		result = NM_PLATFORM_ERROR_NOT_FOUND;
@@ -4471,27 +4513,17 @@ do_change_link_result (NMPlatform *platform,
 		log_level = LOGL_WARN;
 		result = NM_PLATFORM_ERROR_UNSPECIFIED;
 	}
+
+out:
 	_NMLOG (log_level,
 	        "do-change-link[%d]: %s changing link: %s%s",
 	        ifindex,
 	        log_result,
 	        wait_for_nl_response_to_string (seq_result, s_buf, sizeof (s_buf)),
 	        log_detail);
-
 	return result;
 }
 
-static NMPlatformError
-do_change_link (NMPlatform *platform,
-                int ifindex,
-                struct nl_msg *nlmsg)
-{
-	WaitForNlResponseResult seq_result;
-
-	seq_result = do_change_link_request (platform, ifindex, nlmsg);
-	return do_change_link_result (platform, ifindex, seq_result);
-}
-
 static gboolean
 link_add (NMPlatform *platform,
           const char *name,
@@ -4583,7 +4615,7 @@ link_set_netns (NMPlatform *platform,
 		return FALSE;
 
 	NLA_PUT (nlmsg, IFLA_NET_NS_FD, 4, &netns_fd);
-	return do_change_link (platform, ifindex, nlmsg) == NM_PLATFORM_ERROR_SUCCESS;
+	return do_change_link (platform, CHANGE_LINK_TYPE_UNSPEC, ifindex, nlmsg, NULL) == NM_PLATFORM_ERROR_SUCCESS;
 
 nla_put_failure:
 	g_return_val_if_reached (FALSE);
@@ -4613,7 +4645,7 @@ link_change_flags (NMPlatform *platform,
 	                          flags_set);
 	if (!nlmsg)
 		return NM_PLATFORM_ERROR_UNSPECIFIED;
-	return do_change_link (platform, ifindex, nlmsg);
+	return do_change_link (platform, CHANGE_LINK_TYPE_UNSPEC, ifindex, nlmsg, NULL);
 }
 
 static gboolean
@@ -4682,7 +4714,7 @@ link_set_user_ipv6ll_enabled (NMPlatform *platform, int ifindex, gboolean enable
 	    || !_nl_msg_new_link_set_afspec (nlmsg, mode, NULL))
 		g_return_val_if_reached (NM_PLATFORM_ERROR_BUG);
 
-	return do_change_link (platform, ifindex, nlmsg);
+	return do_change_link (platform, CHANGE_LINK_TYPE_UNSPEC, ifindex, nlmsg, NULL);
 }
 
 static gboolean
@@ -4697,7 +4729,7 @@ link_set_token (NMPlatform *platform, int ifindex, NMUtilsIPv6IfaceId iid)
 	if (!nlmsg || !_nl_msg_new_link_set_afspec (nlmsg, -1, &iid))
 		g_return_val_if_reached (FALSE);
 
-	return do_change_link (platform, ifindex, nlmsg) == NM_PLATFORM_ERROR_SUCCESS;
+	return do_change_link (platform, CHANGE_LINK_TYPE_UNSPEC, ifindex, nlmsg, NULL) == NM_PLATFORM_ERROR_SUCCESS;
 }
 
 static gboolean
@@ -4762,8 +4794,12 @@ link_set_address (NMPlatform *platform, int ifindex, gconstpointer address, size
 {
 	nm_auto_nlmsg struct nl_msg *nlmsg = NULL;
 	gs_free char *mac = NULL;
-	WaitForNlResponseResult seq_result;
+	const ChangeLinkData d = {
-	char s_buf[256];
+		.set_address = {
+			.address = address,
+			.length = length,
+		},
+	};
 
 	if (!address || !length)
 		g_return_val_if_reached (NM_PLATFORM_ERROR_BUG);
@@ -4783,30 +4819,7 @@ link_set_address (NMPlatform *platform, int ifindex, gconstpointer address, size
 
 	NLA_PUT (nlmsg, IFLA_ADDRESS, length, address);
 
-	seq_result = do_change_link_request (platform, ifindex, nlmsg);
+	return do_change_link (platform, CHANGE_LINK_TYPE_SET_ADDRESS, ifindex, nlmsg, &d);
-
-	if (NM_IN_SET (-((int) seq_result), ENFILE)) {
-		const NMPObject *obj_cache;
-
-		/* workaround ENFILE which may be wrongly returned (bgo #770456).
-		 * If the MAC address is as expected, assume success? */
-
-		obj_cache = nmp_cache_lookup_link (nm_platform_get_cache (platform), ifindex);
-		if (   obj_cache
-		    && obj_cache->link.addr.len == length
-		    && memcmp (obj_cache->link.addr.data, address, length) == 0) {
-			_NMLOG (LOGL_DEBUG,
-			        "do-change-link[%d]: %s changing link: %s%s",
-			        ifindex,
-			        "success",
-			        wait_for_nl_response_to_string (seq_result, s_buf, sizeof (s_buf)),
-			        " (assume success changing address)");
-			return NM_PLATFORM_ERROR_SUCCESS;
-		}
-	}
-
-	return do_change_link_result (platform, ifindex, seq_result);
-
 nla_put_failure:
 	g_return_val_if_reached (NM_PLATFORM_ERROR_UNSPECIFIED);
 }
@@ -4829,7 +4842,7 @@ link_set_name (NMPlatform *platform, int ifindex, const char *name)
 
 	NLA_PUT (nlmsg, IFLA_IFNAME, strlen (name) + 1, name);
 
-	return do_change_link (platform, ifindex, nlmsg) == NM_PLATFORM_ERROR_SUCCESS;
+	return do_change_link (platform, CHANGE_LINK_TYPE_UNSPEC, ifindex, nlmsg, NULL) == NM_PLATFORM_ERROR_SUCCESS;
 nla_put_failure:
 	g_return_val_if_reached (FALSE);
 }
@@ -4848,7 +4861,7 @@ link_get_permanent_address (NMPlatform *platform,
 	return nmp_utils_ethtool_get_permanent_address (ifindex, buf, length);
 }
 
-static gboolean
+static NMPlatformError
 link_set_mtu (NMPlatform *platform, int ifindex, guint32 mtu)
 {
 	nm_auto_nlmsg struct nl_msg *nlmsg = NULL;
@@ -4866,7 +4879,7 @@ link_set_mtu (NMPlatform *platform, int ifindex, guint32 mtu)
 
 	NLA_PUT_U32 (nlmsg, IFLA_MTU, mtu);
 
-	return do_change_link (platform, ifindex, nlmsg) == NM_PLATFORM_ERROR_SUCCESS;
+	return do_change_link (platform, CHANGE_LINK_TYPE_SET_MTU, ifindex, nlmsg, NULL);
 nla_put_failure:
 	g_return_val_if_reached (FALSE);
 }
@@ -5574,7 +5587,7 @@ link_vlan_change (NMPlatform *platform,
 	                                            new_n_egress_map))
 		g_return_val_if_reached (FALSE);
 
-	return do_change_link (platform, ifindex, nlmsg) == NM_PLATFORM_ERROR_SUCCESS;
+	return do_change_link (platform, CHANGE_LINK_TYPE_UNSPEC, ifindex, nlmsg, NULL) == NM_PLATFORM_ERROR_SUCCESS;
 }
 
 static int
@@ -5654,7 +5667,7 @@ link_enslave (NMPlatform *platform, int master, int slave)
 
 	NLA_PUT_U32 (nlmsg, IFLA_MASTER, master);
 
-	return do_change_link (platform, ifindex, nlmsg) == NM_PLATFORM_ERROR_SUCCESS;
+	return do_change_link (platform, CHANGE_LINK_TYPE_UNSPEC, ifindex, nlmsg, NULL) == NM_PLATFORM_ERROR_SUCCESS;
 nla_put_failure:
 	g_return_val_if_reached (FALSE);
 }

src/platform/nm-platform.c

@@ -240,6 +240,7 @@ NM_UTILS_LOOKUP_STR_DEFINE_STATIC (_nm_platform_error_to_string, NMPlatformError
 	NM_UTILS_LOOKUP_STR_ITEM (NM_PLATFORM_ERROR_NO_FIRMWARE, "no-firmware"),
 	NM_UTILS_LOOKUP_STR_ITEM (NM_PLATFORM_ERROR_OPNOTSUPP,   "not-supported"),
 	NM_UTILS_LOOKUP_STR_ITEM (NM_PLATFORM_ERROR_NETLINK,     "netlink"),
+	NM_UTILS_LOOKUP_STR_ITEM (NM_PLATFORM_ERROR_CANT_SET_MTU, "cant-set-mtu"),
 	NM_UTILS_LOOKUP_ITEM_IGNORE (_NM_PLATFORM_ERROR_MININT),
 );
 
@@ -413,6 +414,7 @@ nm_platform_sysctl_set_ip6_hop_limit_safe (NMPlatform *self, const char *iface,
 {
 	const char *path;
 	gint64 cur;
+	char buf[NM_UTILS_SYSCTL_IP_CONF_PATH_BUFSIZE];
 
 	_CHECK_SELF (self, klass, FALSE);
 
@@ -424,7 +426,7 @@ nm_platform_sysctl_set_ip6_hop_limit_safe (NMPlatform *self, const char *iface,
 	if (value < 10)
 		return FALSE;
 
-	path = nm_utils_ip6_property_path (iface, "hop_limit");
+	path = nm_utils_sysctl_ip_conf_path (AF_INET6, buf, iface, "hop_limit");
 	cur = nm_platform_sysctl_get_int_checked (self, NMP_SYSCTL_PATHID_ABSOLUTE (path), 10, 1, G_MAXINT32, -1);
 
 	/* only allow increasing the hop-limit to avoid DOS by an attacker
@@ -1498,7 +1500,7 @@ nm_platform_link_set_noarp (NMPlatform *self, int ifindex)
  *
  * Set interface MTU.
  */
-gboolean
+NMPlatformError
 nm_platform_link_set_mtu (NMPlatform *self, int ifindex, guint32 mtu)
 {
 	_CHECK_SELF (self, klass, FALSE);

src/platform/nm-platform.h

@@ -166,6 +166,7 @@ typedef enum { /*< skip >*/
 	NM_PLATFORM_ERROR_NO_FIRMWARE,
 	NM_PLATFORM_ERROR_OPNOTSUPP,
 	NM_PLATFORM_ERROR_NETLINK,
+	NM_PLATFORM_ERROR_CANT_SET_MTU,
 } NMPlatformError;
 
 #define NM_PLATFORM_LINK_OTHER_NETNS    (-1)
@@ -718,7 +719,7 @@ typedef struct {
 	                                        guint8 *buf,
 	                                        size_t *length);
 	NMPlatformError (*link_set_address) (NMPlatform *, int ifindex, gconstpointer address, size_t length);
-	gboolean (*link_set_mtu) (NMPlatform *, int ifindex, guint32 mtu);
+	NMPlatformError (*link_set_mtu) (NMPlatform *, int ifindex, guint32 mtu);
 	gboolean (*link_set_name) (NMPlatform *, int ifindex, const char *name);
 	gboolean (*link_set_sriov_num_vfs) (NMPlatform *, int ifindex, guint num_vfs);
 
@@ -1060,7 +1061,7 @@ gboolean nm_platform_link_set_ipv6_token (NMPlatform *self, int ifindex, NMUtils
 
 gboolean nm_platform_link_get_permanent_address (NMPlatform *self, int ifindex, guint8 *buf, size_t *length);
 NMPlatformError nm_platform_link_set_address (NMPlatform *self, int ifindex, const void *address, size_t length);
-gboolean nm_platform_link_set_mtu (NMPlatform *self, int ifindex, guint32 mtu);
+NMPlatformError nm_platform_link_set_mtu (NMPlatform *self, int ifindex, guint32 mtu);
 gboolean nm_platform_link_set_name (NMPlatform *self, int ifindex, const char *name);
 gboolean nm_platform_link_set_sriov_num_vfs (NMPlatform *self, int ifindex, guint num_vfs);
 

src/platform/tests/test-link.c

@@ -76,7 +76,7 @@ test_bogus(void)
 	g_assert (!addrlen);
 	g_assert (!nm_platform_link_get_address (NM_PLATFORM_GET, BOGUS_IFINDEX, NULL));
 
-	g_assert (!nm_platform_link_set_mtu (NM_PLATFORM_GET, BOGUS_IFINDEX, MTU));
+	g_assert (nm_platform_link_set_mtu (NM_PLATFORM_GET, BOGUS_IFINDEX, MTU) != NM_PLATFORM_ERROR_SUCCESS);
 
 	g_assert (!nm_platform_link_get_mtu (NM_PLATFORM_GET, BOGUS_IFINDEX));
 
@@ -603,7 +603,7 @@ test_internal (void)
 	accept_signal (link_changed);
 
 	/* Set MTU */
-	g_assert (nm_platform_link_set_mtu (NM_PLATFORM_GET, ifindex, MTU));
+	g_assert (nm_platform_link_set_mtu (NM_PLATFORM_GET, ifindex, MTU) == NM_PLATFORM_ERROR_SUCCESS);
 	g_assert_cmpint (nm_platform_link_get_mtu (NM_PLATFORM_GET, ifindex), ==, MTU);
 	accept_signal (link_changed);
 

src/tests/test-general.c

@@ -272,6 +272,32 @@ test_nm_utils_log_connection_diff (void)
 
 /*****************************************************************************/
 
+static void
+do_test_sysctl_ip_conf (int addr_family,
+                        const char *iface,
+                        const char *property)
+{
+	char path[NM_UTILS_SYSCTL_IP_CONF_PATH_BUFSIZE];
+	const char *pp;
+
+	pp = nm_utils_sysctl_ip_conf_path (addr_family, path, iface, property);
+	g_assert (pp == path);
+	g_assert (path[0] == '/');
+
+	g_assert (nm_utils_sysctl_ip_conf_is_path (addr_family, path, iface, property));
+	g_assert (nm_utils_sysctl_ip_conf_is_path (addr_family, path, NULL, property));
+}
+
+static void
+test_nm_utils_sysctl_ip_conf_path (void)
+{
+	do_test_sysctl_ip_conf (AF_INET6, "a", "mtu");
+	do_test_sysctl_ip_conf (AF_INET6, "eth0", "mtu");
+	do_test_sysctl_ip_conf (AF_INET6, "e23456789012345", "mtu");
+}
+
+/*****************************************************************************/
+
 static NMConnection *
 _match_connection_new (void)
 {
@@ -1716,6 +1742,8 @@ main (int argc, char **argv)
 	g_test_add_func ("/general/nm_utils_ip6_address_same_prefix", test_nm_utils_ip6_address_same_prefix);
 	g_test_add_func ("/general/nm_utils_log_connection_diff", test_nm_utils_log_connection_diff);
 
+	g_test_add_func ("/general/nm_utils_sysctl_ip_conf_path", test_nm_utils_sysctl_ip_conf_path);
+
 	g_test_add_func ("/general/exp10", test_nm_utils_exp10);
 
 	g_test_add_func ("/general/connection-match/basic", test_connection_match_basic);