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1 /*
2  *  Copyright (c) 2020, The OpenThread Authors.
3  *  All rights reserved.
4  *
5  *  Redistribution and use in source and binary forms, with or without
6  *  modification, are permitted provided that the following conditions are met:
7  *  1. Redistributions of source code must retain the above copyright
8  *     notice, this list of conditions and the following disclaimer.
9  *  2. Redistributions in binary form must reproduce the above copyright
10  *     notice, this list of conditions and the following disclaimer in the
11  *     documentation and/or other materials provided with the distribution.
12  *  3. Neither the name of the copyright holder nor the
13  *     names of its contributors may be used to endorse or promote products
14  *     derived from this software without specific prior written permission.
15  *
16  *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17  *  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  *  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
20  *  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23  *  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24  *  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25  *  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26  *  POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 /**
30  * @file
31  *   This file includes definitions for a time ticker.
32  */
33 
34 #ifndef TIME_TICKER_HPP_
35 #define TIME_TICKER_HPP_
36 
37 #include "openthread-core-config.h"
38 
39 #include "common/locator.hpp"
40 #include "common/non_copyable.hpp"
41 #include "common/numeric_limits.hpp"
42 #include "common/time.hpp"
43 #include "common/timer.hpp"
44 
45 namespace ot {
46 
47 /**
48  * Represents a time ticker.
49  *
50  * The time ticker emits periodic ticks (with 1 second period interval) to a set of registered tick receiver modules.
51  * The tick receivers (OpenThread objects) are identified by the `Receiver` enumeration. The receiver objects
52  * must provide `HandleTimeTick()` method which would be invoked by `TimeTicker` periodically.
53  */
54 class TimeTicker : public InstanceLocator, private NonCopyable
55 {
56 public:
57     /**
58      * Represents time tick receivers.
59      *
60      * Contains the list of all OpenThread modules that can be registered as time tick receivers.
61      */
62     enum Receiver : uint8_t
63     {
64         kMeshForwarder,          ///< `MeshForwarder`
65         kMleRouter,              ///< `Mle::MleRouter`
66         kAddressResolver,        ///< `AddressResolver`
67         kChildSupervisor,        ///< `ChildSupervisor`
68         kIp6FragmentReassembler, ///< `Ip6::Ip6` (handling of fragmented messages)
69         kDuaManager,             ///< `DuaManager`
70         kMlrManager,             ///< `MlrManager`
71         kNetworkDataNotifier,    ///< `NetworkData::Notifier`
72         kIp6Mpl,                 ///< `Ip6::Mpl`
73         kBbrLocal,               ///< `BackboneRouter::Local`
74 
75         kNumReceivers, ///< Number of receivers.
76     };
77 
78     /**
79      * Initializes the `TimeTicker` instance.
80      */
81     explicit TimeTicker(Instance &aInstance);
82 
83     /**
84      * Registers a receiver with `TimeTicker` to receive periodic ticks.
85      *
86      * @param[in] aReceiver   A tick receiver identifier.
87      */
88     void RegisterReceiver(Receiver aReceiver);
89 
90     /**
91      * Unregisters a receiver with `TimeTicker` to receive periodic ticks.
92      *
93      * @param[in] aReceiver   A tick receiver identifier.
94      */
95     void UnregisterReceiver(Receiver aReceiver);
96 
97     /**
98      * Indicates whether a receiver is registered with `TimeTicker` to receive periodic ticks.
99      *
100      * @param[in] aReceiver   A tick receiver identifier.
101      *
102      * @retval TRUE   If @p aReceiver is registered with `TimeTicker`.
103      * @retval FALSE  If @p aReceiver is not registered with `TimeTicker`.
104      */
IsReceiverRegistered(Receiver aReceiver) const105     bool IsReceiverRegistered(Receiver aReceiver) const { return (mReceivers & Mask(aReceiver)) != 0; }
106 
107 private:
108     static constexpr uint32_t kTickInterval  = Time::kOneSecondInMsec;
109     static constexpr uint32_t kRestartJitter = 4; // in msec, jitter added when restarting the timer [-4,+4] ms.
110 
Mask(Receiver aReceiver)111     constexpr static uint32_t Mask(Receiver aReceiver) { return static_cast<uint32_t>(1U) << aReceiver; }
112 
113     void HandleTimer(void);
114 
115     using TickerTimer = TimerMilliIn<TimeTicker, &TimeTicker::HandleTimer>;
116 
117     uint32_t    mReceivers;
118     TickerTimer mTimer;
119 
120     static_assert(kNumReceivers < BitSizeOf(mReceivers), "Too many `Receiver`s - does not fit in a bit mask");
121 };
122 
123 } // namespace ot
124 
125 #endif // TIMER_HPP_
126