core: allow matching IPv6 'link-local' method to 'ignore' (rh #1073824)

When an existing connection profile has IPv6 method 'ignore', NM doesn't simply
care about IPv6. Thus we should allow matching such a profile to devices with
just a link-local address.

The example can be a simple configuration like this:
/etc/sysconfig/network-scripts/ifcfg-ens3:
DEVICE="ens3"
ONBOOT=yes
NETBOOT=yes
UUID="aa17d688-a38d-481d-888d-6d69cca781b8"
BOOTPROTO=dhcp
HWADDR="52:54:00:32:77:59"
TYPE=Ethernet
NAME="ens3"

https://bugzilla.redhat.com/show_bug.cgi?id=1073824

src/NetworkManagerUtils.c

@@ -685,6 +685,37 @@ check_ip6_method_link_local_auto (NMConnection *orig,
 	return FALSE;
 }
 
+static gboolean
+check_ip6_method_link_local_ignore (NMConnection *orig,
+                                    NMConnection *candidate,
+                                    GHashTable *settings)
+{
+	GHashTable *props;
+	const char *orig_ip6_method, *candidate_ip6_method;
+
+	props = g_hash_table_lookup (settings, NM_SETTING_IP6_CONFIG_SETTING_NAME);
+	if (   !props
+	    || (g_hash_table_size (props) != 1)
+	    || !g_hash_table_lookup (props, NM_SETTING_IP6_CONFIG_METHOD)) {
+		/* We only handle ipv6 'method' here */
+		return FALSE;
+	}
+
+	/* If the original connection method is 'link-local' and the candidate method
+	 * is 'ignore' we can take the connection, because NM didn't simply take care
+	 * of IPv6.
+	 */
+	orig_ip6_method = nm_utils_get_ip_config_method (orig, NM_TYPE_SETTING_IP6_CONFIG);
+	candidate_ip6_method = nm_utils_get_ip_config_method (candidate, NM_TYPE_SETTING_IP6_CONFIG);
+
+	if (   strcmp (orig_ip6_method, NM_SETTING_IP6_CONFIG_METHOD_LINK_LOCAL) == 0
+	    && strcmp (candidate_ip6_method, NM_SETTING_IP6_CONFIG_METHOD_IGNORE) == 0) {
+		return TRUE;
+	}
+
+	return FALSE;
+}
+
 static gboolean
 check_ip4_method_disabled_auto (NMConnection *orig,
                                 NMConnection *candidate,
@@ -733,6 +764,9 @@ check_possible_match (NMConnection *orig,
 	if (check_ip6_method_link_local_auto (orig, candidate, settings))
 		return candidate;
 
+	if (check_ip6_method_link_local_ignore (orig, candidate, settings))
+		return candidate;
+
 	if (check_ip4_method_disabled_auto (orig, candidate, settings, device_has_carrier))
 		return candidate;
 

src/tests/test-general.c

@@ -238,6 +238,40 @@ test_connection_match_ip6_method (void)
 	g_object_unref (copy);
 }
 
+static void
+test_connection_match_ip6_method_ignore (void)
+{
+	NMConnection *orig, *copy, *matched;
+	GSList *connections = NULL;
+	NMSettingIP6Config *s_ip6;
+
+	orig = _match_connection_new ();
+	copy = nm_connection_duplicate (orig);
+	connections = g_slist_append (connections, copy);
+
+	/* Check that if the original connection is IPv6 method=link-local, and the
+	 * candidate is method=ignore, that the candidate is matched.
+	 */
+	s_ip6 = nm_connection_get_setting_ip6_config (orig);
+	g_assert (s_ip6);
+	g_object_set (G_OBJECT (s_ip6),
+	              NM_SETTING_IP6_CONFIG_METHOD, NM_SETTING_IP6_CONFIG_METHOD_LINK_LOCAL,
+	              NULL);
+
+	s_ip6 = nm_connection_get_setting_ip6_config (copy);
+	g_assert (s_ip6);
+	g_object_set (G_OBJECT (s_ip6),
+	              NM_SETTING_IP6_CONFIG_METHOD, NM_SETTING_IP6_CONFIG_METHOD_IGNORE,
+	              NULL);
+
+	matched = nm_utils_match_connection (connections, orig, TRUE, NULL, NULL);
+	g_assert (matched == copy);
+
+	g_slist_free (connections);
+	g_object_unref (orig);
+	g_object_unref (copy);
+}
+
 static void
 test_connection_match_ip4_method (void)
 {
@@ -292,6 +326,7 @@ main (int argc, char **argv)
 
 	g_test_add_func ("/general/connection-match/basic", test_connection_match_basic);
 	g_test_add_func ("/general/connection-match/ip6-method", test_connection_match_ip6_method);
+	g_test_add_func ("/general/connection-match/ip6-method-ignore", test_connection_match_ip6_method_ignore);
 	g_test_add_func ("/general/connection-match/ip4-method", test_connection_match_ip4_method);
 
 	return g_test_run ();