src/protocols/secure_channel/StatusReport.cpp

/*
 *
 *    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 <protocols/secure_channel/Constants.h>
#include <protocols/secure_channel/StatusReport.h>

#include <lib/support/BufferReader.h>
#include <lib/support/CodeUtils.h>
#include <lib/support/TypeTraits.h>

#include <type_traits>

using namespace chip::Encoding;
using GeneralStatusCode = chip::Protocols::SecureChannel::GeneralStatusCode;

namespace chip {
namespace Protocols {
namespace SecureChannel {

StatusReport::StatusReport() :
    mGeneralCode(GeneralStatusCode::kSuccess), mProtocolId(SecureChannel::Id), mProtocolCode(0), mProtocolData(nullptr)
{}

StatusReport::StatusReport(GeneralStatusCode generalCode, Protocols::Id protocolId, uint16_t protocolCode) :
    mGeneralCode(generalCode), mProtocolId(protocolId), mProtocolCode(protocolCode), mProtocolData(nullptr)
{}

StatusReport::StatusReport(GeneralStatusCode generalCode, Protocols::Id protocolId, uint16_t protocolCode,
                           System::PacketBufferHandle protocolData) :
    mGeneralCode(generalCode),
    mProtocolId(protocolId), mProtocolCode(protocolCode), mProtocolData(std::move(protocolData))
{}

CHIP_ERROR StatusReport::Parse(System::PacketBufferHandle buf)
{
    uint16_t tempGeneralCode = 0;

    VerifyOrReturnError(!buf.IsNull(), CHIP_ERROR_INVALID_ARGUMENT);

    uint8_t * bufStart = buf->Start();
    LittleEndian::Reader bufReader(bufStart, buf->DataLength());

    uint32_t protocolId;
    ReturnErrorOnFailure(bufReader.Read16(&tempGeneralCode).Read32(&protocolId).Read16(&mProtocolCode).StatusCode());
    mProtocolId  = Protocols::Id::FromFullyQualifiedSpecForm(protocolId);
    mGeneralCode = static_cast<GeneralStatusCode>(tempGeneralCode);

    // Any data that exists after the required fields is considered protocol-specific data.
    if (bufReader.OctetsRead() < buf->DataLength())
    {
        mProtocolData = System::PacketBufferHandle::NewWithData(buf->Start() + bufReader.OctetsRead(),
                                                                buf->DataLength() - bufReader.OctetsRead(),
                                                                /* aAdditionalSize = */ 0, /* aReservedSize = */ 0);
        if (mProtocolData.IsNull())
        {
            return CHIP_ERROR_NO_MEMORY;
        }
    }
    else
    {
        mProtocolData = nullptr;
    }

    return CHIP_NO_ERROR;
}

Encoding::LittleEndian::BufferWriter & StatusReport::WriteToBuffer(Encoding::LittleEndian::BufferWriter & buf) const
{
    buf.Put16(to_underlying(mGeneralCode)).Put32(mProtocolId.ToFullyQualifiedSpecForm()).Put16(mProtocolCode);
    if (!mProtocolData.IsNull())
    {
        buf.Put(mProtocolData->Start(), mProtocolData->DataLength());
    }
    return buf;
}

size_t StatusReport::Size() const
{
    LittleEndian::BufferWriter emptyBuf(nullptr, 0);
    return WriteToBuffer(emptyBuf).Needed();
}

System::PacketBufferHandle StatusReport::MakeBusyStatusReportMessage(System::Clock::Milliseconds16 minimumWaitTime)
{
    using namespace Protocols::SecureChannel;
    constexpr uint8_t kBusyStatusReportProtocolDataSize = sizeof(minimumWaitTime.count()); // 16-bits

    auto handle = System::PacketBufferHandle::New(kBusyStatusReportProtocolDataSize, 0);
    VerifyOrReturnValue(!handle.IsNull(), handle,
                        ChipLogError(SecureChannel, "Failed to allocate protocol data for busy status report"));

    // Build the protocol data with minimum wait time
    Encoding::LittleEndian::PacketBufferWriter protocolDataBufferWriter(std::move(handle));
    protocolDataBufferWriter.Put16(minimumWaitTime.count());
    handle = protocolDataBufferWriter.Finalize();
    VerifyOrReturnValue(!handle.IsNull(), handle,
                        ChipLogError(SecureChannel, "Failed to finalize protocol data for busy status report"));

    // Build a busy status report
    StatusReport statusReport(GeneralStatusCode::kBusy, Protocols::SecureChannel::Id, kProtocolCodeBusy, std::move(handle));

    // Build the status report message
    handle = System::PacketBufferHandle::New(statusReport.Size());
    VerifyOrReturnValue(!handle.IsNull(), handle, ChipLogError(SecureChannel, "Failed to allocate status report message"));
    Encoding::LittleEndian::PacketBufferWriter bbuf(std::move(handle));

    statusReport.WriteToBuffer(bbuf);
    return bbuf.Finalize();
}

} // namespace SecureChannel
} // namespace Protocols
} // namespace chip