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/**
*
* Copyright (c) 2020 Project CHIP Authors
*
* 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.
*/
/**
* @file
* This file describes a Manual Entry Code Generator.
*
*/
#include "ManualSetupPayloadGenerator.h"
#include <inttypes.h>
#include <lib/support/logging/CHIPLogging.h>
#include <lib/support/verhoeff/Verhoeff.h>
namespace chip {
static uint32_t chunk1PayloadRepresentation(const PayloadContents & payload)
{
/* <1 digit> Represents:
* - <bits 1..0> Discriminator <bits 11.10>
* - <bit 2> VID/PID present flag
*/
constexpr int kDiscriminatorShift = (kManualSetupDiscriminatorFieldLengthInBits - kManualSetupChunk1DiscriminatorMsbitsLength);
constexpr uint32_t kDiscriminatorMask = (1 << kManualSetupChunk1DiscriminatorMsbitsLength) - 1;
static_assert(kManualSetupChunk1VidPidPresentBitPos >=
kManualSetupChunk1DiscriminatorMsbitsPos + kManualSetupChunk1DiscriminatorMsbitsLength,
"Discriminator won't fit");
uint32_t discriminatorChunk = (payload.discriminator.GetShortValue() >> kDiscriminatorShift) & kDiscriminatorMask;
uint32_t vidPidPresentFlag = payload.commissioningFlow != CommissioningFlow::kStandard ? 1 : 0;
uint32_t result = (discriminatorChunk << kManualSetupChunk1DiscriminatorMsbitsPos) |
(vidPidPresentFlag << kManualSetupChunk1VidPidPresentBitPos);
return result;
}
static uint32_t chunk2PayloadRepresentation(const PayloadContents & payload)
{
/* <5 digits> Represents:
* - <bits 13..0> PIN Code <bits 13..0>
* - <bits 15..14> Discriminator <bits 9..8>
*/
constexpr uint32_t kDiscriminatorMask = (1 << kManualSetupChunk2DiscriminatorLsbitsLength) - 1;
constexpr uint32_t kPincodeMask = (1 << kManualSetupChunk2PINCodeLsbitsLength) - 1;
uint32_t discriminatorChunk = payload.discriminator.GetShortValue() & kDiscriminatorMask;
uint32_t result = ((payload.setUpPINCode & kPincodeMask) << kManualSetupChunk2PINCodeLsbitsPos) |
(discriminatorChunk << kManualSetupChunk2DiscriminatorLsbitsPos);
return result;
}
static uint32_t chunk3PayloadRepresentation(const PayloadContents & payload)
{
/* <4 digits> Represents:
* - <bits 12..0> PIN Code <bits 26..14>
*/
constexpr int kPincodeShift = (kSetupPINCodeFieldLengthInBits - kManualSetupChunk3PINCodeMsbitsLength);
constexpr uint32_t kPincodeMask = (1 << kManualSetupChunk3PINCodeMsbitsLength) - 1;
uint32_t result = ((payload.setUpPINCode >> kPincodeShift) & kPincodeMask) << kManualSetupChunk3PINCodeMsbitsPos;
return result;
}
static CHIP_ERROR decimalStringWithPadding(MutableCharSpan buffer, uint32_t number)
{
int len = static_cast<int>(buffer.size() - 1);
int retval = snprintf(buffer.data(), buffer.size(), "%0*" PRIu32, len, number);
return (retval >= static_cast<int>(buffer.size())) ? CHIP_ERROR_BUFFER_TOO_SMALL : CHIP_NO_ERROR;
}
CHIP_ERROR ManualSetupPayloadGenerator::payloadDecimalStringRepresentation(MutableCharSpan & outBuffer)
{
static_assert(kManualSetupCodeChunk1CharLength + kManualSetupCodeChunk2CharLength + kManualSetupCodeChunk3CharLength ==
kManualSetupShortCodeCharLength,
"Manual code length mismatch (short)");
static_assert(kManualSetupShortCodeCharLength + kManualSetupVendorIdCharLength + kManualSetupProductIdCharLength ==
kManualSetupLongCodeCharLength,
"Manual code length mismatch (long)");
static_assert(kManualSetupChunk1DiscriminatorMsbitsLength + kManualSetupChunk2DiscriminatorLsbitsLength ==
kManualSetupDiscriminatorFieldLengthInBits,
"Discriminator won't fit");
static_assert(kManualSetupChunk2PINCodeLsbitsLength + kManualSetupChunk3PINCodeMsbitsLength == kSetupPINCodeFieldLengthInBits,
"PIN code won't fit");
if (!mAllowInvalidPayload && !mPayloadContents.isValidManualCode())
{
ChipLogError(SetupPayload, "Failed encoding invalid payload");
return CHIP_ERROR_INVALID_ARGUMENT;
}
bool useLongCode = (mPayloadContents.commissioningFlow != CommissioningFlow::kStandard) && !mForceShortCode;
// Add two for the check digit and null terminator.
if ((useLongCode && outBuffer.size() < kManualSetupLongCodeCharLength + 2) ||
(!useLongCode && outBuffer.size() < kManualSetupShortCodeCharLength + 2))
{
ChipLogError(SetupPayload, "Failed encoding payload to buffer");
return CHIP_ERROR_BUFFER_TOO_SMALL;
}
uint32_t chunk1 = chunk1PayloadRepresentation(mPayloadContents);
uint32_t chunk2 = chunk2PayloadRepresentation(mPayloadContents);
uint32_t chunk3 = chunk3PayloadRepresentation(mPayloadContents);
size_t offset = 0;
// Add one to the length of each chunk, since snprintf writes a null terminator.
ReturnErrorOnFailure(decimalStringWithPadding(outBuffer.SubSpan(offset, kManualSetupCodeChunk1CharLength + 1), chunk1));
offset += kManualSetupCodeChunk1CharLength;
ReturnErrorOnFailure(decimalStringWithPadding(outBuffer.SubSpan(offset, kManualSetupCodeChunk2CharLength + 1), chunk2));
offset += kManualSetupCodeChunk2CharLength;
ReturnErrorOnFailure(decimalStringWithPadding(outBuffer.SubSpan(offset, kManualSetupCodeChunk3CharLength + 1), chunk3));
offset += kManualSetupCodeChunk3CharLength;
if (useLongCode)
{
ReturnErrorOnFailure(
decimalStringWithPadding(outBuffer.SubSpan(offset, kManualSetupVendorIdCharLength + 1), mPayloadContents.vendorID));
offset += kManualSetupVendorIdCharLength;
ReturnErrorOnFailure(
decimalStringWithPadding(outBuffer.SubSpan(offset, kManualSetupProductIdCharLength + 1), mPayloadContents.productID));
offset += kManualSetupProductIdCharLength;
}
int checkDigit = Verhoeff10::CharToVal(Verhoeff10::ComputeCheckChar(outBuffer.data()));
ReturnErrorOnFailure(decimalStringWithPadding(outBuffer.SubSpan(offset, 2), static_cast<uint32_t>(checkDigit)));
offset += 1;
// Reduce outBuffer span size to be the size of written data and to not include null-terminator.
outBuffer.reduce_size(offset);
return CHIP_NO_ERROR;
}
CHIP_ERROR ManualSetupPayloadGenerator::payloadDecimalStringRepresentation(std::string & outDecimalString)
{
// One extra char for the check digit, another for the null terminator.
char decimalString[kManualSetupLongCodeCharLength + 1 + 1] = "";
MutableCharSpan outBuffer(decimalString);
ReturnErrorOnFailure(payloadDecimalStringRepresentation(outBuffer));
outDecimalString.assign(decimalString);
return CHIP_NO_ERROR;
}
} // namespace chip