DTNTPWorker.h

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/*
 * DTNTPWorker.h
 *
 * Copyright (C) 2011 IBR, TU Braunschweig
 *
 * Written-by: Johannes Morgenroth <morgenroth@ibr.cs.tu-bs.de>
 *
 * 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.
 *
 */

#ifndef DTNTPWORKER_H_
#define DTNTPWORKER_H_

#include "core/AbstractWorker.h"
#include "core/EventReceiver.h"
#include "net/DiscoveryBeaconHandler.h"
#include "Configuration.h"
#include <time.h>

namespace dtn
{
        namespace daemon
        {
                class DTNTPWorker : public dtn::core::AbstractWorker, public dtn::core::EventReceiver, public dtn::net::DiscoveryBeaconHandler
                {
                public:
                        DTNTPWorker();

                        virtual ~DTNTPWorker();

                        void callbackBundleReceived(const Bundle &b);

                        void raiseEvent(const dtn::core::Event *evt) throw ();

                        void onUpdateBeacon(const ibrcommon::vinterface &iface, DiscoveryBeacon &announcement)
                                throw(NoServiceHereException);

                        class TimeSyncMessage
                        {
                        public:
                                enum MSG_TYPE
                                {
                                        TIMESYNC_REQUEST = 1,
                                        TIMESYNC_RESPONSE = 2
                                };

                                TimeSyncMessage();
                                ~TimeSyncMessage();

                                MSG_TYPE type;

                                timeval origin_timestamp;
                                double origin_rating;

                                timeval peer_timestamp;
                                double peer_rating;

                                friend std::ostream &operator<<(std::ostream &stream, const DTNTPWorker::TimeSyncMessage &obj);
                                friend std::istream &operator>>(std::istream &stream, DTNTPWorker::TimeSyncMessage &obj);
                        };

                        class TimeSyncState {
                        public:
                                TimeSyncState();
                                virtual ~TimeSyncState();

                                // sync threshold
                                float sync_threshold;

                                // the base rating used to determine the current clock rating
                                double base_rating;

                                // the local rating is at least decremented by this value between each synchronization
                                double psi;

                                // current value for sigma
                                double sigma;

                                // timestamp of the last synchronization with another (better) clock
                                struct timespec last_sync_time;

                                // defines if the last_sync_time is set
                                bool last_sync_set;

                                static double toDouble(const timespec &val);
                        };

                        static const TimeSyncState& getState();

                private:
                        class SyncPeer {
                        public:
                                SyncPeer();
                                virtual ~SyncPeer();

                                enum State {
                                        STATE_IDLE = 0,
                                        STATE_PREPARE = 1,
                                        STATE_REQUEST = 2,
                                        STATE_SYNC = 3
                                };

                                void touch();

                                bool isExpired() const;

                                State state;
                                struct timespec request_monotonic_time;
                                timeval request_timestamp;

                        private:
                                dtn::data::Timestamp _touched;
                        };

                        static const unsigned int PROTO_VERSION;
                        static const std::string TAG;

                        bool shouldSyncWith(const dtn::core::Node &node) const;

                        void syncWith(const dtn::core::Node &node);

                        bool hasReference() const;

                        void decode(const dtn::core::Node::Attribute &attr, unsigned int &version, dtn::data::Timestamp &timestamp, float &quality) const;

                        void sync(const TimeSyncMessage &msg, const struct timeval &tv, const struct timeval &local, const struct timeval &remote);

                        static TimeSyncState _sync_state;

                        // send discovery announcements with the local clock rating
                        bool _announce_rating;

                        // synchronize with other nodes
                        bool _sync;

                        // Mutex to lock the synchronization process
                        ibrcommon::Mutex _sync_lock;

                        // manage a list of recently sync'd nodes
                        ibrcommon::Mutex _peer_lock;
                        typedef std::map<EID, SyncPeer> peer_map;
                        peer_map _peers;
                };
        }
}

#endif /* DTNTPWORKER_H_ */