// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you 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.

#ifndef __LINUX_ROUTING_QUEUEING_FQ_CODEL_HPP__
#define __LINUX_ROUTING_QUEUEING_FQ_CODEL_HPP__

#include <stdint.h>

#include <string>

#include <stout/hashmap.hpp>
#include <stout/try.hpp>

#include "linux/routing/handle.hpp"

namespace routing {
namespace queueing {
namespace fq_codel {

constexpr char KIND[] = "fq_codel";


// NOTE: Root queueing discipline handle has to be X:0, so handle's
// secondary number has to be 0 here. There can be only one root
// queueing discipline on the egress side of a link and fq_codel is
// classless and hence there is only one instance of fq_codel per
// link. This allows us to fix the fq_codel handle.


// The default number of flows for the fq_codel queueing discipline.
extern const int DEFAULT_FLOWS;


// Returns true if there exists an fq_codel queueing discipline on the
// egress side of the link.
Try<bool> exists(
    const std::string& link,
    const Handle& parent);


// Creates a new fq_codel queueing discipline on the egress side of
// the link. Returns false if a queueing discipline already exists.
// NOTE: The root queueing discipline handle has to be X:0, so
// handle's secondary number must be zero if the parent is attached to
// EGRESS_ROOT.
Try<bool> create(
    const std::string& link,
    const Handle& parent,
    const Option<Handle>& handle);


// Removes the fq_codel queueing discipline from the link. Return
// false if the fq_codel queueing discipline is not found.
Try<bool> remove(
    const std::string& link,
    const Handle& parent);


// Returns the set of common Traffic Control statistics for the
// fq_codel queueing discipline on the link, None() if the link or
// qdisc does not exist or an error if we cannot cannot determine the
// result.
Result<hashmap<std::string, uint64_t>> statistics(
    const std::string& link,
    const Handle& parent);


} // namespace fq_codel {
} // namespace queueing {
} // namespace routing {

#endif // __LINUX_ROUTING_QUEUEING_FQ_CODEL_HPP__