Line data    Source code

       1              : /*
       2              :  *    Copyright (c) 2024 Project CHIP Authors
       3              :  *    All rights reserved.
       4              :  *
       5              :  *    Licensed under the Apache License, Version 2.0 (the "License");
       6              :  *    you may not use this file except in compliance with the License.
       7              :  *    You may obtain a copy of the License at
       8              :  *
       9              :  *        http://www.apache.org/licenses/LICENSE-2.0
      10              :  *
      11              :  *    Unless required by applicable law or agreed to in writing, software
      12              :  *    distributed under the License is distributed on an "AS IS" BASIS,
      13              :  *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      14              :  *    See the License for the specific language governing permissions and
      15              :  *    limitations under the License.
      16              :  */
      17              : 
      18              : /**
      19              :  * @brief The file implements the Matter Check-In counter
      20              :  *
      21              :  */
      22              : #pragma once
      23              : 
      24              : #include <crypto/RandUtils.h>
      25              : #include <lib/core/CHIPError.h>
      26              : #include <lib/support/PersistedCounter.h>
      27              : 
      28              : namespace chip {
      29              : namespace Protocols {
      30              : namespace SecureChannel {
      31              : 
      32              : /**
      33              :  * @brief
      34              :  *
      35              :  */
      36              : class CheckInCounter : public PersistedCounter<uint32_t>
      37              : {
      38              : public:
      39           75 :     CheckInCounter(){};
      40           75 :     ~CheckInCounter() override{};
      41              : 
      42              :     /**
      43              :      * @brief Returns the next Check-In counter Value to use
      44              :      *
      45              :      * @return uint32_t Check-in Counter value to use
      46              :      */
      47              :     inline uint32_t GetNextCheckInCounterValue() { return (mCounterValue + 1); };
      48              : 
      49              :     /**
      50              :      * @brief Advances the current Check-In counter value to invalidate half of the values.
      51              :      *        Function adds UINT32_MAX / 2 to the current counter value. Next time a Check-In message is sent, 1 is added to the
      52              :      *        current value.
      53              :      *
      54              :      * @return CHIP_ERROR Any error returned by a write to persisted storage.
      55              :      */
      56              :     CHIP_ERROR InvalidateHalfCheckInCounterValues();
      57              : 
      58              :     /**
      59              :      * @brief Invalidates all the Check-In counter values. After this function is called, the new Check-In counter value will be
      60              :      *        equal to current value minus 1 (with rollover) to mimic N -> UINT32_MAX -> N-1. Next time a Check-In message is sent,
      61              :      *        1 is added to the current value which will be an invalid counter value.
      62              :      *
      63              :      * @return CHIP_ERROR Any error returned by a write to persisted storage.
      64              :      */
      65              :     CHIP_ERROR InvalidateAllCheckInCounterValues();
      66              : 
      67              : private:
      68              :     /**
      69              :      * @brief Get the Initial Counter Value for the Check-In counter
      70              :      *        Initial value is randomized for the Check-In counter
      71              :      *
      72              :      * @return uint32_t random value
      73              :      */
      74            0 :     inline uint32_t GetInitialCounterValue() override { return chip::Crypto::GetRandU32(); }
      75              : };
      76              : 
      77              : } // namespace SecureChannel
      78              : } // namespace Protocols
      79              : } // namespace chip