Line data    Source code

       1              : /*
       2              :  *    Copyright (c) 2022 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              :  *    @file
      20              :  *      This file defines the CHIP CASE Session object that provides
      21              :  *      APIs for constructing a secure session using a certificate from the device's
      22              :  *      operational credentials.
      23              :  */
      24              : 
      25              : #pragma once
      26              : 
      27              : #include <lib/core/TLV.h>
      28              : #include <lib/support/DefaultStorageKeyAllocator.h>
      29              : #include <protocols/secure_channel/DefaultSessionResumptionStorage.h>
      30              : 
      31              : namespace chip {
      32              : 
      33              : /**
      34              :  * An example SessionResumptionStorage using PersistentStorageDelegate as it backend.
      35              :  */
      36              : class SimpleSessionResumptionStorage : public DefaultSessionResumptionStorage
      37              : {
      38              : public:
      39            8 :     CHIP_ERROR Init(PersistentStorageDelegate * storage)
      40              :     {
      41            8 :         VerifyOrReturnError(storage != nullptr, CHIP_ERROR_INVALID_ARGUMENT);
      42            8 :         mStorage = storage;
      43            8 :         return CHIP_NO_ERROR;
      44              :     }
      45              : 
      46              :     CHIP_ERROR SaveIndex(const SessionIndex & index) override;
      47              :     CHIP_ERROR LoadIndex(SessionIndex & index) override;
      48              : 
      49              :     CHIP_ERROR SaveLink(ConstResumptionIdView resumptionId, const ScopedNodeId & node) override;
      50              :     CHIP_ERROR LoadLink(ConstResumptionIdView resumptionId, ScopedNodeId & node) override;
      51              :     CHIP_ERROR DeleteLink(ConstResumptionIdView resumptionId) override;
      52              : 
      53              :     CHIP_ERROR SaveState(const ScopedNodeId & node, ConstResumptionIdView resumptionId,
      54              :                          const Crypto::P256ECDHDerivedSecret & sharedSecret, const CATValues & peerCATs) override;
      55              :     CHIP_ERROR LoadState(const ScopedNodeId & node, ResumptionIdStorage & resumptionId,
      56              :                          Crypto::P256ECDHDerivedSecret & sharedSecret, CATValues & peerCATs) override;
      57              :     CHIP_ERROR DeleteState(const ScopedNodeId & node) override;
      58              : 
      59              :     static StorageKeyName GetStorageKey(const ScopedNodeId & node);
      60              :     static StorageKeyName GetStorageKey(ConstResumptionIdView resumptionId);
      61              : 
      62              : private:
      63              :     static constexpr size_t MaxScopedNodeIdSize() { return TLV::EstimateStructOverhead(sizeof(NodeId), sizeof(FabricIndex)); }
      64              : 
      65              :     static constexpr size_t MaxIndexSize()
      66              :     {
      67              :         // The max size of the list is (1 byte control + bytes for actual value) times max number of list items
      68              :         // Constant product inside a CHIPConfig.h macro; cannot widen at the use site.
      69              :         // NOLINTNEXTLINE(bugprone-implicit-widening-of-multiplication-result)
      70              :         return TLV::EstimateStructOverhead((1 + MaxScopedNodeIdSize()) * CHIP_CONFIG_CASE_SESSION_RESUME_CACHE_SIZE);
      71              :     }
      72              : 
      73              :     static constexpr size_t MaxStateSize()
      74              :     {
      75              :         return TLV::EstimateStructOverhead(kResumptionIdSize, Crypto::P256ECDHDerivedSecret::Capacity(),
      76              :                                            CATValues::kSerializedLength);
      77              :     }
      78              : 
      79              :     static constexpr TLV::Tag kFabricIndexTag  = TLV::ContextTag(1);
      80              :     static constexpr TLV::Tag kPeerNodeIdTag   = TLV::ContextTag(2);
      81              :     static constexpr TLV::Tag kResumptionIdTag = TLV::ContextTag(3);
      82              :     static constexpr TLV::Tag kSharedSecretTag = TLV::ContextTag(4);
      83              :     static constexpr TLV::Tag kCATTag          = TLV::ContextTag(5);
      84              : 
      85              :     PersistentStorageDelegate * mStorage;
      86              : };
      87              : 
      88              : } // namespace chip