/*

 * 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;

}