examples/ota-provider-app/ota-provider-common/OTAProviderExample.cpp - third_party/github/project-chip/connectedhomeip - Git at Google

 /*
  *
  *    Copyright (c) 2021 Project CHIP Authors
  *    All rights reserved.
  *
  *    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.
  */

 #include <ota-provider-common/OTAProviderExample.h>

 #include <algorithm>
 #include <app-common/zap-generated/cluster-objects.h>
 #include <app/clusters/ota-provider/ota-provider-delegate.h>
 #include <app/server/Server.h>
 #include <credentials/FabricTable.h>
 #include <crypto/RandUtils.h>
 #include <lib/core/TLV.h>
 #include <lib/support/CHIPMemString.h>
 #include <protocols/bdx/BdxUri.h>

 #include <fstream>
 #include <string.h>

 using chip::BitFlags;
 using chip::ByteSpan;
 using chip::CharSpan;
 using chip::FabricIndex;
 using chip::FabricInfo;
 using chip::MutableCharSpan;
 using chip::NodeId;
 using chip::Optional;
 using chip::Server;
 using chip::Span;
 using chip::app::Clusters::OTAProviderDelegate;
 using chip::bdx::TransferControlFlags;
 using chip::Protocols::InteractionModel::Status;
 using namespace chip;
 using namespace chip::ota;
 using namespace chip::app::Clusters::OtaSoftwareUpdateProvider;
 using namespace chip::app::Clusters::OtaSoftwareUpdateProvider::Commands;

 constexpr uint8_t kUpdateTokenLen    = 32;                      // must be between 8 and 32
 constexpr uint8_t kUpdateTokenStrLen = kUpdateTokenLen * 2 + 1; // Hex string needs 2 hex chars for every byte
 constexpr size_t kOtaHeaderMaxSize   = 1024;

 // Arbitrary BDX Transfer Params
 constexpr uint32_t kMaxBdxBlockSize                = 1024;
 constexpr chip::System::Clock::Timeout kBdxTimeout = chip::System::Clock::Seconds16(5 * 60); // OTA Spec mandates >= 5 minutes
 constexpr uint32_t kBdxServerPollIntervalMillis    = 50;                                     // poll every 50ms by default

 void GetUpdateTokenString(const chip::ByteSpan & token, char * buf, size_t bufSize)
 {
     const uint8_t * tokenData = static_cast<const uint8_t *>(token.data());
     size_t minLength          = std::min(token.size(), bufSize);
     for (size_t i = 0; i < (minLength / 2) - 1; ++i)
     {
         snprintf(&buf[i * 2], bufSize, "%02X", tokenData[i]);
     }
 }

 void GenerateUpdateToken(uint8_t * buf, size_t bufSize)
 {
     for (size_t i = 0; i < bufSize; ++i)
     {
         buf[i] = chip::Crypto::GetRandU8();
     }
 }

 OTAProviderExample::OTAProviderExample()
 {
     memset(mOTAFilePath, 0, sizeof(mOTAFilePath));
     memset(mImageUri, 0, sizeof(mImageUri));
     mIgnoreQueryImageCount     = 0;
     mIgnoreApplyUpdateCount    = 0;
     mQueryImageStatus          = OTAQueryStatus::kNotAvailable;
     mUpdateAction              = OTAApplyUpdateAction::kDiscontinue;
     mDelayedQueryActionTimeSec = 0;
     mDelayedApplyActionTimeSec = 0;
     mUserConsentDelegate       = nullptr;
     mUserConsentNeeded         = false;
     mPollInterval              = kBdxServerPollIntervalMillis;
     mCandidates.clear();
 }

 void OTAProviderExample::SetOTAFilePath(const char * path)
 {
     if (path != nullptr)
     {
         chip::Platform::CopyString(mOTAFilePath, path);
     }
     else
     {
         memset(mOTAFilePath, 0, sizeof(mOTAFilePath));
     }
 }

 void OTAProviderExample::SetImageUri(const char * imageUri)
 {
     if (imageUri != nullptr)
     {
         chip::Platform::CopyString(mImageUri, imageUri);
     }
     else
     {
         memset(mImageUri, 0, sizeof(mImageUri));
     }
 }

 void OTAProviderExample::SetOTACandidates(std::vector<OTAProviderExample::DeviceSoftwareVersionModel> candidates)
 {
     mCandidates = std::move(candidates);

     // Validate that each candidate matches the info in the image header
     for (auto candidate : mCandidates)
     {
         OTAImageHeaderParser parser;
         OTAImageHeader header;
         ParseOTAHeader(parser, candidate.otaURL, header);

         ChipLogDetail(SoftwareUpdate, "Validating image list candidate %s: ", candidate.otaURL);
         VerifyOrDie(candidate.vendorId == header.mVendorId);
         VerifyOrDie(candidate.productId == header.mProductId);
         VerifyOrDie(candidate.softwareVersion == header.mSoftwareVersion);
         VerifyOrDie(strlen(candidate.softwareVersionString) == header.mSoftwareVersionString.size());
         VerifyOrDie(memcmp(candidate.softwareVersionString, header.mSoftwareVersionString.data(),
                            header.mSoftwareVersionString.size()) == 0);
         if (header.mMinApplicableVersion.HasValue())
         {
             VerifyOrDie(candidate.minApplicableSoftwareVersion == header.mMinApplicableVersion.Value());
         }
         if (header.mMaxApplicableVersion.HasValue())
         {
             VerifyOrDie(candidate.maxApplicableSoftwareVersion == header.mMaxApplicableVersion.Value());
         }
         parser.Clear();
     }
 }

 static bool CompareSoftwareVersions(const OTAProviderExample::DeviceSoftwareVersionModel & a,
                                     const OTAProviderExample::DeviceSoftwareVersionModel & b)
 {
     return (a.softwareVersion < b.softwareVersion);
 }

 bool OTAProviderExample::SelectOTACandidate(const uint16_t requestorVendorID, const uint16_t requestorProductID,
                                             const uint32_t requestorSoftwareVersion,
                                             OTAProviderExample::DeviceSoftwareVersionModel & finalCandidate)
 {
     bool candidateFound = false;
     std::sort(mCandidates.begin(), mCandidates.end(), CompareSoftwareVersions);
     for (auto candidate : mCandidates)
     {
         // VendorID and ProductID will be the primary key when querying
         // the DCL servers. If not we can add the vendor/product ID checks here.
         if (candidate.softwareVersionValid && requestorSoftwareVersion < candidate.softwareVersion &&
             requestorSoftwareVersion >= candidate.minApplicableSoftwareVersion &&
             requestorSoftwareVersion <= candidate.maxApplicableSoftwareVersion)
         {
             candidateFound = true;
             finalCandidate = candidate;
         }
     }
     return candidateFound;
 }

 UserConsentSubject OTAProviderExample::GetUserConsentSubject(const app::CommandHandler * commandObj,
                                                              const app::ConcreteCommandPath & commandPath,
                                                              const QueryImage::DecodableType & commandData, uint32_t targetVersion)
 {
     UserConsentSubject subject;
     subject.fabricIndex             = commandObj->GetSubjectDescriptor().fabricIndex;
     subject.requestorNodeId         = commandObj->GetSubjectDescriptor().subject;
     subject.providerEndpointId      = commandPath.mEndpointId;
     subject.requestorVendorId       = commandData.vendorID;
     subject.requestorProductId      = commandData.productID;
     subject.requestorCurrentVersion = commandData.softwareVersion;
     subject.requestorTargetVersion  = targetVersion;
     if (commandData.metadataForProvider.HasValue())
     {
         subject.metadata = commandData.metadataForProvider.Value();
     }
     return subject;
 }

 bool OTAProviderExample::ParseOTAHeader(OTAImageHeaderParser & parser, const char * otaFilePath, OTAImageHeader & header)
 {
     uint8_t otaFileContent[kOtaHeaderMaxSize];
     ByteSpan buffer(otaFileContent);

     std::ifstream otaFile(otaFilePath, std::ifstream::in);
     if (!otaFile.is_open() || !otaFile.good())
     {
         ChipLogError(SoftwareUpdate, "Error opening OTA image file: %s", otaFilePath);
         return false;
     }

     otaFile.read(reinterpret_cast<char *>(otaFileContent), kOtaHeaderMaxSize);
     if (otaFile.bad())
     {
         ChipLogError(SoftwareUpdate, "Error reading OTA image file: %s", otaFilePath);
         return false;
     }

     parser.Init();
     if (!parser.IsInitialized())
     {
         return false;
     }

     CHIP_ERROR error = parser.AccumulateAndDecode(buffer, header);
     if (error != CHIP_NO_ERROR)
     {
         ChipLogError(SoftwareUpdate, "Error parsing OTA image header: %" CHIP_ERROR_FORMAT, error.Format());
         return false;
     }

     return true;
 }

 void OTAProviderExample::SendQueryImageResponse(app::CommandHandler * commandObj, const app::ConcreteCommandPath & commandPath,
                                                 const QueryImage::DecodableType & commandData)
 {
     VerifyOrReturn(commandObj != nullptr, ChipLogError(SoftwareUpdate, "Invalid commandObj, cannot send QueryImageResponse"));

     QueryImageResponse::Type response;
     bool requestorCanConsent             = commandData.requestorCanConsent.ValueOr(false);
     uint8_t updateToken[kUpdateTokenLen] = { 0 };
     char strBuf[kUpdateTokenStrLen]      = { 0 };

     // Set fields specific for an available status response
     if (mQueryImageStatus == OTAQueryStatus::kUpdateAvailable)
     {
         GenerateUpdateToken(updateToken, kUpdateTokenLen);
         GetUpdateTokenString(ByteSpan(updateToken), strBuf, kUpdateTokenStrLen);
         ChipLogDetail(SoftwareUpdate, "Generated updateToken: %s", strBuf);

         // TODO: This uses the current node as the provider to supply the OTA image. This can be configurable such that the
         // provider supplying the response is not the provider supplying the OTA image.
         FabricIndex fabricIndex       = commandObj->GetAccessingFabricIndex();
         const FabricInfo * fabricInfo = Server::GetInstance().GetFabricTable().FindFabricWithIndex(fabricIndex);
         NodeId nodeId                 = fabricInfo->GetPeerId().GetNodeId();

         // Generate the ImageURI if one is not already preset
         if (strlen(mImageUri) == 0)
         {
             // Only supporting BDX protocol for now
             MutableCharSpan uri(mImageUri);
             CHIP_ERROR error = chip::bdx::MakeURI(nodeId, CharSpan::fromCharString(mOTAFilePath), uri);
             if (error != CHIP_NO_ERROR)
             {
                 ChipLogError(SoftwareUpdate, "Cannot generate URI");
                 memset(mImageUri, 0, sizeof(mImageUri));
             }
             else
             {
                 ChipLogDetail(SoftwareUpdate, "Generated URI: %s", mImageUri);
             }
         }

         // Initialize the transfer session in prepartion for a BDX transfer
         BitFlags<TransferControlFlags> bdxFlags;
         bdxFlags.Set(TransferControlFlags::kReceiverDrive);
         if (mBdxOtaSender.InitializeTransfer(commandObj->GetSubjectDescriptor().fabricIndex,
                                              commandObj->GetSubjectDescriptor().subject) == CHIP_NO_ERROR)
         {
             CHIP_ERROR error =
                 mBdxOtaSender.PrepareForTransfer(&chip::DeviceLayer::SystemLayer(), chip::bdx::TransferRole::kSender, bdxFlags,
                                                  kMaxBdxBlockSize, kBdxTimeout, chip::System::Clock::Milliseconds32(mPollInterval));
             if (error != CHIP_NO_ERROR)
             {
                 ChipLogError(SoftwareUpdate, "Cannot prepare for transfer: %" CHIP_ERROR_FORMAT, error.Format());
                 commandObj->AddStatus(commandPath, Status::Failure);
                 return;
             }

             response.imageURI.Emplace(chip::CharSpan::fromCharString(mImageUri));
             response.softwareVersion.Emplace(mSoftwareVersion);
             response.softwareVersionString.Emplace(chip::CharSpan::fromCharString(mSoftwareVersionString));
             response.updateToken.Emplace(chip::ByteSpan(updateToken));
         }
         else
         {
             // Another BDX transfer in progress
             mQueryImageStatus = OTAQueryStatus::kBusy;
         }
     }

     // Delay action time is only applicable when the provider is busy
     if (mQueryImageStatus == OTAQueryStatus::kBusy)
     {
         response.delayedActionTime.Emplace(mDelayedQueryActionTimeSec);
     }

     // Set remaining fields common to all status types
     response.status = mQueryImageStatus;
     if (mUserConsentNeeded && requestorCanConsent)
     {
         response.userConsentNeeded.Emplace(true);
     }
     else
     {
         response.userConsentNeeded.Emplace(false);
     }
     // For test coverage, sending empty metadata when (requestorNodeId % 2) == 0 and not sending otherwise.
     if (commandObj->GetSubjectDescriptor().subject % 2 == 0)
     {
         response.metadataForRequestor.Emplace(chip::ByteSpan());
     }

     // Either sends the response or an error status
     commandObj->AddResponse(commandPath, response);
 }

 void OTAProviderExample::HandleQueryImage(app::CommandHandler * commandObj, const app::ConcreteCommandPath & commandPath,
                                           const QueryImage::DecodableType & commandData)
 {
     bool requestorCanConsent = commandData.requestorCanConsent.ValueOr(false);

     if (mIgnoreQueryImageCount > 0)
     {
         ChipLogDetail(SoftwareUpdate, "Skip sending QueryImageResponse, ignore count: %" PRIu32, mIgnoreQueryImageCount);
         mIgnoreQueryImageCount--;
         return;
     }

     if (mQueryImageStatus == OTAQueryStatus::kUpdateAvailable)
     {
         memset(mSoftwareVersionString, 0, sizeof(mSoftwareVersionString));

         if (!mCandidates.empty()) // If list of OTA candidates is supplied
         {
             OTAProviderExample::DeviceSoftwareVersionModel candidate;
             if (SelectOTACandidate(commandData.vendorID, commandData.productID, commandData.softwareVersion, candidate))
             {
                 VerifyOrDie(sizeof(mSoftwareVersionString) > strlen(candidate.softwareVersionString));

                 // This assumes all candidates have passed verification so the values are safe to use
                 mSoftwareVersion = candidate.softwareVersion;
                 memcpy(mSoftwareVersionString, candidate.softwareVersionString, strlen(candidate.softwareVersionString));
                 SetOTAFilePath(candidate.otaURL);
             }
         }
         else if (strlen(mOTAFilePath) > 0) // If OTA file is directly provided
         {
             // Parse the header and set version info based on the header
             OTAImageHeaderParser parser;
             OTAImageHeader header;
             VerifyOrDie(ParseOTAHeader(parser, mOTAFilePath, header) == true);
             VerifyOrDie(sizeof(mSoftwareVersionString) > header.mSoftwareVersionString.size());
             mSoftwareVersion = header.mSoftwareVersion;
             memcpy(mSoftwareVersionString, header.mSoftwareVersionString.data(), header.mSoftwareVersionString.size());
             parser.Clear();
         }

         // If mUserConsentNeeded (set by the CLI) is true and requestor is capable of taking user consent
         // then delegate obtaining user consent to the requestor
         if (mUserConsentDelegate && (requestorCanConsent && mUserConsentNeeded) == false)
         {
             UserConsentState state = mUserConsentDelegate->GetUserConsentState(
                 GetUserConsentSubject(commandObj, commandPath, commandData, mSoftwareVersion));
             ChipLogProgress(SoftwareUpdate, "User Consent state: %s", mUserConsentDelegate->UserConsentStateToString(state));
             switch (state)
             {
             case UserConsentState::kGranted:
                 mQueryImageStatus = OTAQueryStatus::kUpdateAvailable;
                 break;

             case UserConsentState::kObtaining:
                 mQueryImageStatus = OTAQueryStatus::kBusy;
                 break;

             case UserConsentState::kDenied:
             case UserConsentState::kUnknown:
                 mQueryImageStatus = OTAQueryStatus::kNotAvailable;
                 break;
             }
         }
     }

     // Guarantees that either a response or an error status is sent
     SendQueryImageResponse(commandObj, commandPath, commandData);

     // After the first response is sent, default to these values for subsequent queries
     mQueryImageStatus          = OTAQueryStatus::kUpdateAvailable;
     mDelayedQueryActionTimeSec = 0;
 }

 void OTAProviderExample::HandleApplyUpdateRequest(app::CommandHandler * commandObj, const app::ConcreteCommandPath & commandPath,
                                                   const ApplyUpdateRequest::DecodableType & commandData)
 {
     VerifyOrReturn(commandObj != nullptr, ChipLogError(SoftwareUpdate, "Invalid commandObj, cannot handle ApplyUpdateRequest"));

     if (mIgnoreApplyUpdateCount > 0)
     {
         ChipLogDetail(SoftwareUpdate, "Skip sending ApplyUpdateResponse, ignore count %" PRIu32, mIgnoreApplyUpdateCount);
         mIgnoreApplyUpdateCount--;
         return;
     }

     // TODO: handle multiple transfers by tracking updateTokens
     char tokenBuf[kUpdateTokenStrLen] = { 0 };

     GetUpdateTokenString(commandData.updateToken, tokenBuf, kUpdateTokenStrLen);
     ChipLogDetail(SoftwareUpdate, "%s: token: %s, version: %" PRIu32, __FUNCTION__, tokenBuf, commandData.newVersion);

     ApplyUpdateResponse::Type response;
     response.action            = mUpdateAction;
     response.delayedActionTime = mDelayedApplyActionTimeSec;

     // Reset delay back to 0 for subsequent uses
     mDelayedApplyActionTimeSec = 0;
     // Reset back to success case for subsequent uses
     mUpdateAction = OTAApplyUpdateAction::kProceed;

     // Either sends the response or an error status
     commandObj->AddResponse(commandPath, response);
 }

 void OTAProviderExample::HandleNotifyUpdateApplied(app::CommandHandler * commandObj, const app::ConcreteCommandPath & commandPath,
                                                    const NotifyUpdateApplied::DecodableType & commandData)
 {
     VerifyOrReturn(commandObj != nullptr, ChipLogError(SoftwareUpdate, "Invalid commandObj, cannot handle NotifyUpdateApplied"));

     char tokenBuf[kUpdateTokenStrLen] = { 0 };

     GetUpdateTokenString(commandData.updateToken, tokenBuf, kUpdateTokenStrLen);
     ChipLogDetail(SoftwareUpdate, "%s: token: %s, version: %" PRIu32, __FUNCTION__, tokenBuf, commandData.softwareVersion);

     commandObj->AddStatus(commandPath, Status::Success);
 }
	/*
	*
	* Copyright (c) 2021 Project CHIP Authors
	* All rights reserved.
	*
	* 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.
	*/

	#include <ota-provider-common/OTAProviderExample.h>

	#include <algorithm>
	#include <app-common/zap-generated/cluster-objects.h>
	#include <app/clusters/ota-provider/ota-provider-delegate.h>
	#include <app/server/Server.h>
	#include <credentials/FabricTable.h>
	#include <crypto/RandUtils.h>
	#include <lib/core/TLV.h>
	#include <lib/support/CHIPMemString.h>
	#include <protocols/bdx/BdxUri.h>

	#include <fstream>
	#include <string.h>

	using chip::BitFlags;
	using chip::ByteSpan;
	using chip::CharSpan;
	using chip::FabricIndex;
	using chip::FabricInfo;
	using chip::MutableCharSpan;
	using chip::NodeId;
	using chip::Optional;
	using chip::Server;
	using chip::Span;
	using chip::app::Clusters::OTAProviderDelegate;
	using chip::bdx::TransferControlFlags;
	using chip::Protocols::InteractionModel::Status;
	using namespace chip;
	using namespace chip::ota;
	using namespace chip::app::Clusters::OtaSoftwareUpdateProvider;
	using namespace chip::app::Clusters::OtaSoftwareUpdateProvider::Commands;

	constexpr uint8_t kUpdateTokenLen = 32; // must be between 8 and 32
	constexpr uint8_t kUpdateTokenStrLen = kUpdateTokenLen * 2 + 1; // Hex string needs 2 hex chars for every byte
	constexpr size_t kOtaHeaderMaxSize = 1024;

	// Arbitrary BDX Transfer Params
	constexpr uint32_t kMaxBdxBlockSize = 1024;
	constexpr chip::System::Clock::Timeout kBdxTimeout = chip::System::Clock::Seconds16(5 * 60); // OTA Spec mandates >= 5 minutes
	constexpr uint32_t kBdxServerPollIntervalMillis = 50; // poll every 50ms by default

	void GetUpdateTokenString(const chip::ByteSpan & token, char * buf, size_t bufSize)
	{
	const uint8_t * tokenData = static_cast<const uint8_t *>(token.data());
	size_t minLength = std::min(token.size(), bufSize);
	for (size_t i = 0; i < (minLength / 2) - 1; ++i)
	{
	snprintf(&buf[i * 2], bufSize, "%02X", tokenData[i]);
	}
	}

	void GenerateUpdateToken(uint8_t * buf, size_t bufSize)
	{
	for (size_t i = 0; i < bufSize; ++i)
	{
	buf[i] = chip::Crypto::GetRandU8();
	}
	}

	OTAProviderExample::OTAProviderExample()
	{
	memset(mOTAFilePath, 0, sizeof(mOTAFilePath));
	memset(mImageUri, 0, sizeof(mImageUri));
	mIgnoreQueryImageCount = 0;
	mIgnoreApplyUpdateCount = 0;
	mQueryImageStatus = OTAQueryStatus::kNotAvailable;
	mUpdateAction = OTAApplyUpdateAction::kDiscontinue;
	mDelayedQueryActionTimeSec = 0;
	mDelayedApplyActionTimeSec = 0;
	mUserConsentDelegate = nullptr;
	mUserConsentNeeded = false;
	mPollInterval = kBdxServerPollIntervalMillis;
	mCandidates.clear();
	}

	void OTAProviderExample::SetOTAFilePath(const char * path)
	{
	if (path != nullptr)
	{
	chip::Platform::CopyString(mOTAFilePath, path);
	}
	else
	{
	memset(mOTAFilePath, 0, sizeof(mOTAFilePath));
	}
	}

	void OTAProviderExample::SetImageUri(const char * imageUri)
	{
	if (imageUri != nullptr)
	{
	chip::Platform::CopyString(mImageUri, imageUri);
	}
	else
	{
	memset(mImageUri, 0, sizeof(mImageUri));
	}
	}

	void OTAProviderExample::SetOTACandidates(std::vector<OTAProviderExample::DeviceSoftwareVersionModel> candidates)
	{
	mCandidates = std::move(candidates);

	// Validate that each candidate matches the info in the image header
	for (auto candidate : mCandidates)
	{
	OTAImageHeaderParser parser;
	OTAImageHeader header;
	ParseOTAHeader(parser, candidate.otaURL, header);

	ChipLogDetail(SoftwareUpdate, "Validating image list candidate %s: ", candidate.otaURL);
	VerifyOrDie(candidate.vendorId == header.mVendorId);
	VerifyOrDie(candidate.productId == header.mProductId);
	VerifyOrDie(candidate.softwareVersion == header.mSoftwareVersion);
	VerifyOrDie(strlen(candidate.softwareVersionString) == header.mSoftwareVersionString.size());
	VerifyOrDie(memcmp(candidate.softwareVersionString, header.mSoftwareVersionString.data(),
	header.mSoftwareVersionString.size()) == 0);
	if (header.mMinApplicableVersion.HasValue())
	{
	VerifyOrDie(candidate.minApplicableSoftwareVersion == header.mMinApplicableVersion.Value());
	}
	if (header.mMaxApplicableVersion.HasValue())
	{
	VerifyOrDie(candidate.maxApplicableSoftwareVersion == header.mMaxApplicableVersion.Value());
	}
	parser.Clear();
	}
	}

	static bool CompareSoftwareVersions(const OTAProviderExample::DeviceSoftwareVersionModel & a,
	const OTAProviderExample::DeviceSoftwareVersionModel & b)
	{
	return (a.softwareVersion < b.softwareVersion);
	}

	bool OTAProviderExample::SelectOTACandidate(const uint16_t requestorVendorID, const uint16_t requestorProductID,
	const uint32_t requestorSoftwareVersion,
	OTAProviderExample::DeviceSoftwareVersionModel & finalCandidate)
	{
	bool candidateFound = false;
	std::sort(mCandidates.begin(), mCandidates.end(), CompareSoftwareVersions);
	for (auto candidate : mCandidates)
	{
	// VendorID and ProductID will be the primary key when querying
	// the DCL servers. If not we can add the vendor/product ID checks here.
	if (candidate.softwareVersionValid && requestorSoftwareVersion < candidate.softwareVersion &&
	requestorSoftwareVersion >= candidate.minApplicableSoftwareVersion &&
	requestorSoftwareVersion <= candidate.maxApplicableSoftwareVersion)
	{
	candidateFound = true;
	finalCandidate = candidate;
	}
	}
	return candidateFound;
	}

	UserConsentSubject OTAProviderExample::GetUserConsentSubject(const app::CommandHandler * commandObj,
	const app::ConcreteCommandPath & commandPath,
	const QueryImage::DecodableType & commandData, uint32_t targetVersion)
	{
	UserConsentSubject subject;
	subject.fabricIndex = commandObj->GetSubjectDescriptor().fabricIndex;
	subject.requestorNodeId = commandObj->GetSubjectDescriptor().subject;
	subject.providerEndpointId = commandPath.mEndpointId;
	subject.requestorVendorId = commandData.vendorID;
	subject.requestorProductId = commandData.productID;
	subject.requestorCurrentVersion = commandData.softwareVersion;
	subject.requestorTargetVersion = targetVersion;
	if (commandData.metadataForProvider.HasValue())
	{
	subject.metadata = commandData.metadataForProvider.Value();
	}
	return subject;
	}

	bool OTAProviderExample::ParseOTAHeader(OTAImageHeaderParser & parser, const char * otaFilePath, OTAImageHeader & header)
	{
	uint8_t otaFileContent[kOtaHeaderMaxSize];
	ByteSpan buffer(otaFileContent);

	std::ifstream otaFile(otaFilePath, std::ifstream::in);
	if (!otaFile.is_open() \|\| !otaFile.good())
	{
	ChipLogError(SoftwareUpdate, "Error opening OTA image file: %s", otaFilePath);
	return false;
	}

	otaFile.read(reinterpret_cast<char *>(otaFileContent), kOtaHeaderMaxSize);
	if (otaFile.bad())
	{
	ChipLogError(SoftwareUpdate, "Error reading OTA image file: %s", otaFilePath);
	return false;
	}

	parser.Init();
	if (!parser.IsInitialized())
	{
	return false;
	}

	CHIP_ERROR error = parser.AccumulateAndDecode(buffer, header);
	if (error != CHIP_NO_ERROR)
	{
	ChipLogError(SoftwareUpdate, "Error parsing OTA image header: %" CHIP_ERROR_FORMAT, error.Format());
	return false;
	}

	return true;
	}

	void OTAProviderExample::SendQueryImageResponse(app::CommandHandler * commandObj, const app::ConcreteCommandPath & commandPath,
	const QueryImage::DecodableType & commandData)
	{
	VerifyOrReturn(commandObj != nullptr, ChipLogError(SoftwareUpdate, "Invalid commandObj, cannot send QueryImageResponse"));

	QueryImageResponse::Type response;
	bool requestorCanConsent = commandData.requestorCanConsent.ValueOr(false);
	uint8_t updateToken[kUpdateTokenLen] = { 0 };
	char strBuf[kUpdateTokenStrLen] = { 0 };

	// Set fields specific for an available status response
	if (mQueryImageStatus == OTAQueryStatus::kUpdateAvailable)
	{
	GenerateUpdateToken(updateToken, kUpdateTokenLen);
	GetUpdateTokenString(ByteSpan(updateToken), strBuf, kUpdateTokenStrLen);
	ChipLogDetail(SoftwareUpdate, "Generated updateToken: %s", strBuf);

	// TODO: This uses the current node as the provider to supply the OTA image. This can be configurable such that the
	// provider supplying the response is not the provider supplying the OTA image.
	FabricIndex fabricIndex = commandObj->GetAccessingFabricIndex();
	const FabricInfo * fabricInfo = Server::GetInstance().GetFabricTable().FindFabricWithIndex(fabricIndex);
	NodeId nodeId = fabricInfo->GetPeerId().GetNodeId();

	// Generate the ImageURI if one is not already preset
	if (strlen(mImageUri) == 0)
	{
	// Only supporting BDX protocol for now
	MutableCharSpan uri(mImageUri);
	CHIP_ERROR error = chip::bdx::MakeURI(nodeId, CharSpan::fromCharString(mOTAFilePath), uri);
	if (error != CHIP_NO_ERROR)
	{
	ChipLogError(SoftwareUpdate, "Cannot generate URI");
	memset(mImageUri, 0, sizeof(mImageUri));
	}
	else
	{
	ChipLogDetail(SoftwareUpdate, "Generated URI: %s", mImageUri);
	}
	}

	// Initialize the transfer session in prepartion for a BDX transfer
	BitFlags<TransferControlFlags> bdxFlags;
	bdxFlags.Set(TransferControlFlags::kReceiverDrive);
	if (mBdxOtaSender.InitializeTransfer(commandObj->GetSubjectDescriptor().fabricIndex,
	commandObj->GetSubjectDescriptor().subject) == CHIP_NO_ERROR)
	{
	CHIP_ERROR error =
	mBdxOtaSender.PrepareForTransfer(&chip::DeviceLayer::SystemLayer(), chip::bdx::TransferRole::kSender, bdxFlags,
	kMaxBdxBlockSize, kBdxTimeout, chip::System::Clock::Milliseconds32(mPollInterval));
	if (error != CHIP_NO_ERROR)
	{
	ChipLogError(SoftwareUpdate, "Cannot prepare for transfer: %" CHIP_ERROR_FORMAT, error.Format());
	commandObj->AddStatus(commandPath, Status::Failure);
	return;
	}

	response.imageURI.Emplace(chip::CharSpan::fromCharString(mImageUri));
	response.softwareVersion.Emplace(mSoftwareVersion);
	response.softwareVersionString.Emplace(chip::CharSpan::fromCharString(mSoftwareVersionString));
	response.updateToken.Emplace(chip::ByteSpan(updateToken));
	}
	else
	{
	// Another BDX transfer in progress
	mQueryImageStatus = OTAQueryStatus::kBusy;
	}
	}

	// Delay action time is only applicable when the provider is busy
	if (mQueryImageStatus == OTAQueryStatus::kBusy)
	{
	response.delayedActionTime.Emplace(mDelayedQueryActionTimeSec);
	}

	// Set remaining fields common to all status types
	response.status = mQueryImageStatus;
	if (mUserConsentNeeded && requestorCanConsent)
	{
	response.userConsentNeeded.Emplace(true);
	}
	else
	{
	response.userConsentNeeded.Emplace(false);
	}
	// For test coverage, sending empty metadata when (requestorNodeId % 2) == 0 and not sending otherwise.
	if (commandObj->GetSubjectDescriptor().subject % 2 == 0)
	{
	response.metadataForRequestor.Emplace(chip::ByteSpan());
	}

	// Either sends the response or an error status
	commandObj->AddResponse(commandPath, response);
	}

	void OTAProviderExample::HandleQueryImage(app::CommandHandler * commandObj, const app::ConcreteCommandPath & commandPath,
	const QueryImage::DecodableType & commandData)
	{
	bool requestorCanConsent = commandData.requestorCanConsent.ValueOr(false);

	if (mIgnoreQueryImageCount > 0)
	{
	ChipLogDetail(SoftwareUpdate, "Skip sending QueryImageResponse, ignore count: %" PRIu32, mIgnoreQueryImageCount);
	mIgnoreQueryImageCount--;
	return;
	}

	if (mQueryImageStatus == OTAQueryStatus::kUpdateAvailable)
	{
	memset(mSoftwareVersionString, 0, sizeof(mSoftwareVersionString));

	if (!mCandidates.empty()) // If list of OTA candidates is supplied
	{
	OTAProviderExample::DeviceSoftwareVersionModel candidate;
	if (SelectOTACandidate(commandData.vendorID, commandData.productID, commandData.softwareVersion, candidate))
	{
	VerifyOrDie(sizeof(mSoftwareVersionString) > strlen(candidate.softwareVersionString));

	// This assumes all candidates have passed verification so the values are safe to use
	mSoftwareVersion = candidate.softwareVersion;
	memcpy(mSoftwareVersionString, candidate.softwareVersionString, strlen(candidate.softwareVersionString));
	SetOTAFilePath(candidate.otaURL);
	}
	}
	else if (strlen(mOTAFilePath) > 0) // If OTA file is directly provided
	{
	// Parse the header and set version info based on the header
	OTAImageHeaderParser parser;
	OTAImageHeader header;
	VerifyOrDie(ParseOTAHeader(parser, mOTAFilePath, header) == true);
	VerifyOrDie(sizeof(mSoftwareVersionString) > header.mSoftwareVersionString.size());
	mSoftwareVersion = header.mSoftwareVersion;
	memcpy(mSoftwareVersionString, header.mSoftwareVersionString.data(), header.mSoftwareVersionString.size());
	parser.Clear();
	}

	// If mUserConsentNeeded (set by the CLI) is true and requestor is capable of taking user consent
	// then delegate obtaining user consent to the requestor
	if (mUserConsentDelegate && (requestorCanConsent && mUserConsentNeeded) == false)
	{
	UserConsentState state = mUserConsentDelegate->GetUserConsentState(
	GetUserConsentSubject(commandObj, commandPath, commandData, mSoftwareVersion));
	ChipLogProgress(SoftwareUpdate, "User Consent state: %s", mUserConsentDelegate->UserConsentStateToString(state));
	switch (state)
	{
	case UserConsentState::kGranted:
	mQueryImageStatus = OTAQueryStatus::kUpdateAvailable;
	break;

	case UserConsentState::kObtaining:
	mQueryImageStatus = OTAQueryStatus::kBusy;
	break;

	case UserConsentState::kDenied:
	case UserConsentState::kUnknown:
	mQueryImageStatus = OTAQueryStatus::kNotAvailable;
	break;
	}
	}
	}

	// Guarantees that either a response or an error status is sent
	SendQueryImageResponse(commandObj, commandPath, commandData);

	// After the first response is sent, default to these values for subsequent queries
	mQueryImageStatus = OTAQueryStatus::kUpdateAvailable;
	mDelayedQueryActionTimeSec = 0;
	}

	void OTAProviderExample::HandleApplyUpdateRequest(app::CommandHandler * commandObj, const app::ConcreteCommandPath & commandPath,
	const ApplyUpdateRequest::DecodableType & commandData)
	{
	VerifyOrReturn(commandObj != nullptr, ChipLogError(SoftwareUpdate, "Invalid commandObj, cannot handle ApplyUpdateRequest"));

	if (mIgnoreApplyUpdateCount > 0)
	{
	ChipLogDetail(SoftwareUpdate, "Skip sending ApplyUpdateResponse, ignore count %" PRIu32, mIgnoreApplyUpdateCount);
	mIgnoreApplyUpdateCount--;
	return;
	}

	// TODO: handle multiple transfers by tracking updateTokens
	char tokenBuf[kUpdateTokenStrLen] = { 0 };

	GetUpdateTokenString(commandData.updateToken, tokenBuf, kUpdateTokenStrLen);
	ChipLogDetail(SoftwareUpdate, "%s: token: %s, version: %" PRIu32, __FUNCTION__, tokenBuf, commandData.newVersion);

	ApplyUpdateResponse::Type response;
	response.action = mUpdateAction;
	response.delayedActionTime = mDelayedApplyActionTimeSec;

	// Reset delay back to 0 for subsequent uses
	mDelayedApplyActionTimeSec = 0;
	// Reset back to success case for subsequent uses
	mUpdateAction = OTAApplyUpdateAction::kProceed;

	// Either sends the response or an error status
	commandObj->AddResponse(commandPath, response);
	}

	void OTAProviderExample::HandleNotifyUpdateApplied(app::CommandHandler * commandObj, const app::ConcreteCommandPath & commandPath,
	const NotifyUpdateApplied::DecodableType & commandData)
	{
	VerifyOrReturn(commandObj != nullptr, ChipLogError(SoftwareUpdate, "Invalid commandObj, cannot handle NotifyUpdateApplied"));

	char tokenBuf[kUpdateTokenStrLen] = { 0 };

	GetUpdateTokenString(commandData.updateToken, tokenBuf, kUpdateTokenStrLen);
	ChipLogDetail(SoftwareUpdate, "%s: token: %s, version: %" PRIu32, __FUNCTION__, tokenBuf, commandData.softwareVersion);

	commandObj->AddStatus(commandPath, Status::Success);
	}