netdev: Globally track port status changes

[sliver-openvswitch.git] / lib / connectivity.c

diff --git a/lib/connectivity.c b/lib/connectivity.c
new file mode 100644 (file)
index 0000000..c80b5f1
--- /dev/null
+++ b/lib/connectivity.c
@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2013 Nicira, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <config.h>
+#include "connectivity.h"
+#include "ovs-thread.h"
+#include "seq.h"
+
+static struct seq *connectivity_seq;
+
+/* Provides a global seq for connectivity changes.
+ *
+ * Connectivity monitoring modules should call seq_change() on the returned
+ * object whenever the status of a port changes, whether the cause is local or
+ * remote.
+ *
+ * Clients can seq_wait() on this object for changes to netdev flags, features,
+ * ethernet addresses, carrier changes, and bfd/cfm/lacp/stp status. */
+struct seq *
+connectivity_seq_get(void)
+{
+    static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
+
+    if (ovsthread_once_start(&once)) {
+        connectivity_seq = seq_create();
+        ovsthread_once_done(&once);
+    }
+
+    return connectivity_seq;
+}