core: add configuration flag to choose slaves activation order

Commits 39d0559d9a ("platform: sort links by name instead of
ifindex") and 529a0a1a7f ("manager: sort slaves to be autoconnected
by device name") changed the order of activation of slaves. Introduce
a system-wide configuration property to preserve the old behavior.

https://bugzilla.redhat.com/show_bug.cgi?id=1452585
(cherry picked from commit 31656a066b)

man/NetworkManager.conf.xml

@@ -409,6 +409,19 @@ no-auto-default=*
         </listitem>
       </varlistentry>
 
+      <varlistentry>
+        <term><varname>slaves-order</varname></term>
+        <listitem>
+          <para>
+            This key specifies in which order slave connections are
+            auto-activated on boot or when the master activates
+            them. Allowed values are <literal>name</literal> (order
+            connection by interface name, the default), or
+            <literal>index</literal> (order slaves by their kernel
+            index).
+          </para>
+        </listitem>
+      </varlistentry>
     </variablelist>
   </refsect1>
 

src/nm-config.h

@@ -63,6 +63,7 @@
 #define NM_CONFIG_KEYFILE_KEY_MAIN_DHCP                     "dhcp"
 #define NM_CONFIG_KEYFILE_KEY_MAIN_DEBUG                    "debug"
 #define NM_CONFIG_KEYFILE_KEY_MAIN_HOSTNAME_MODE            "hostname-mode"
+#define NM_CONFIG_KEYFILE_KEY_MAIN_SLAVES_ORDER             "slaves-order"
 #define NM_CONFIG_KEYFILE_KEY_LOGGING_BACKEND               "backend"
 #define NM_CONFIG_KEYFILE_KEY_CONFIG_ENABLE                 "enable"
 #define NM_CONFIG_KEYFILE_KEY_ATOMIC_SECTION_WAS            ".was"

src/nm-manager.c

@@ -2459,10 +2459,14 @@ platform_query_devices (NMManager *self)
 	NMPlatformLink *links;
 	int i;
 	gboolean guess_assume;
+	const char *order;
 
 	guess_assume = nm_config_get_first_start (nm_config_get ());
-
+	order = nm_config_data_get_value_cached (NM_CONFIG_GET_DATA,
-	links_array = nm_platform_link_get_all (NM_PLATFORM_GET);
+	                                         NM_CONFIG_KEYFILE_GROUP_MAIN,
+	                                         NM_CONFIG_KEYFILE_KEY_MAIN_SLAVES_ORDER,
+	                                         NM_CONFIG_GET_VALUE_STRIP);
+	links_array = nm_platform_link_get_all (NM_PLATFORM_GET, !nm_streq0 (order, "index"));
 	links = (NMPlatformLink *) links_array->data;
 	for (i = 0; i < links_array->len; i++) {
 		gs_free NMConfigDeviceStateData *dev_state = NULL;
@@ -3016,7 +3020,7 @@ out:
 }
 
 static gint
-compare_slaves (gconstpointer a, gconstpointer b, gpointer _unused)
+compare_slaves (gconstpointer a, gconstpointer b, gpointer sort_by_name)
 {
 	const SlaveConnectionInfo *a_info = a;
 	const SlaveConnectionInfo *b_info = b;
@@ -3027,8 +3031,12 @@ compare_slaves (gconstpointer a, gconstpointer b, gpointer _unused)
 	if (!b_info->device)
 		return -1;
 
-	return g_strcmp0 (nm_device_get_iface (a_info->device),
+	if (GPOINTER_TO_INT (sort_by_name)) {
-	                  nm_device_get_iface (b_info->device));
+		return g_strcmp0 (nm_device_get_iface (a_info->device),
+		                  nm_device_get_iface (b_info->device));
+	}
+
+	return nm_device_get_ifindex (a_info->device) - nm_device_get_ifindex (b_info->device);
 }
 
 static void
@@ -3042,11 +3050,17 @@ autoconnect_slaves (NMManager *self,
 	if (should_connect_slaves (NM_CONNECTION (master_connection), master_device)) {
 		gs_free SlaveConnectionInfo *slaves = NULL;
 		guint i, n_slaves = 0;
+		const char *value;
 
 		slaves = find_slaves (self, master_connection, master_device, &n_slaves);
 		if (n_slaves > 1) {
+			value = nm_config_data_get_value_cached (NM_CONFIG_GET_DATA,
+			                                         NM_CONFIG_KEYFILE_GROUP_MAIN,
+			                                         NM_CONFIG_KEYFILE_KEY_MAIN_SLAVES_ORDER,
+			                                         NM_CONFIG_GET_VALUE_STRIP);
 			g_qsort_with_data (slaves, n_slaves, sizeof (slaves[0]),
-			                   compare_slaves, NULL);
+			                   compare_slaves,
+			                   GINT_TO_POINTER (!nm_streq0 (value, "index")));
 		}
 
 		for (i = 0; i < n_slaves; i++) {

src/platform/nm-platform.c

@@ -437,7 +437,8 @@ nm_platform_sysctl_get_int_checked (NMPlatform *self, const char *pathid, int di
 
 static int
 _link_get_all_presort (gconstpointer  p_a,
-                       gconstpointer  p_b)
+                       gconstpointer  p_b,
+                       gpointer       sort_by_name)
 {
 	const NMPlatformLink *a = p_a;
 	const NMPlatformLink *b = p_b;
@@ -448,13 +449,16 @@ _link_get_all_presort (gconstpointer  p_a,
 	if (b->ifindex == 1)
 		return 1;
 
-	/* Initialized links first */
+	if (GPOINTER_TO_INT (sort_by_name)) {
-	if (a->initialized > b->initialized)
+		/* Initialized links first */
-		return -1;
+		if (a->initialized > b->initialized)
-	if (a->initialized < b->initialized)
+			return -1;
-		return 1;
+		if (a->initialized < b->initialized)
+			return 1;
 
-	return strcmp (a->name, b->name);
+		return strcmp (a->name, b->name);
+	} else
+		return a->ifindex - b->ifindex;
 }
 
 /**
@@ -465,7 +469,7 @@ _link_get_all_presort (gconstpointer  p_a,
  * owned by the caller and should be freed with g_array_unref().
  */
 GArray *
-nm_platform_link_get_all (NMPlatform *self)
+nm_platform_link_get_all (NMPlatform *self, gboolean sort_by_name)
 {
 	GArray *links, *result;
 	guint i, j, nresult;
@@ -479,9 +483,9 @@ nm_platform_link_get_all (NMPlatform *self)
 	if (!links || links->len == 0)
 		return links;
 
-	/* first sort the links by their ifindex. Below we will sort further by moving
+	/* first sort the links by their ifindex or name. Below we will sort
-	 * children/slaves to the end. */
+	 * further by moving children/slaves to the end. */
-	g_array_sort (links, _link_get_all_presort);
+	g_array_sort_with_data (links, _link_get_all_presort, GINT_TO_POINTER (sort_by_name));
 
 	unseen = g_hash_table_new (g_direct_hash, g_direct_equal);
 	for (i = 0; i < links->len; i++) {

src/platform/nm-platform.h

@@ -763,7 +763,7 @@ const NMPlatformLink *nm_platform_link_get (NMPlatform *self, int ifindex);
 const NMPlatformLink *nm_platform_link_get_by_ifname (NMPlatform *self, const char *ifname);
 const NMPlatformLink *nm_platform_link_get_by_address (NMPlatform *self, gconstpointer address, size_t length);
 
-GArray *nm_platform_link_get_all (NMPlatform *self);
+GArray *nm_platform_link_get_all (NMPlatform *self, gboolean sort_by_name);
 NMPlatformError nm_platform_link_dummy_add (NMPlatform *self, const char *name, const NMPlatformLink **out_link);
 NMPlatformError nm_platform_link_bridge_add (NMPlatform *self, const char *name, const void *address, size_t address_len, const NMPlatformLink **out_link);
 NMPlatformError nm_platform_link_bond_add (NMPlatform *self, const char *name, const NMPlatformLink **out_link);

src/platform/tests/test-common.c

@@ -185,7 +185,7 @@ link_callback (NMPlatform *platform, int obj_type_i, int ifindex, NMPlatformLink
 
 	/* Check the data */
 	g_assert (received->ifindex > 0);
-	links = nm_platform_link_get_all (NM_PLATFORM_GET);
+	links = nm_platform_link_get_all (NM_PLATFORM_GET, TRUE);
 	for (i = 0; i < links->len; i++) {
 		cached = &g_array_index (links, NMPlatformLink, i);
 		if (cached->ifindex == received->ifindex) {

src/platform/tests/test-general.c

@@ -48,7 +48,7 @@ test_link_get_all (void)
 
 	platform = nm_linux_platform_new (TRUE, NM_PLATFORM_NETNS_SUPPORT_DEFAULT);
 
-	links = nm_platform_link_get_all (platform);
+	links = nm_platform_link_get_all (platform, TRUE);
 }
 
 /*****************************************************************************/