src/ble/CHIPBleServiceData.h

/*
 *
 *    Copyright (c) 2020 Project CHIP Authors
 *    Copyright (c) 2019 Google LLC.
 *
 *    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
 *          Definitions for chip BLE service advertisement data.
 */

#pragma once

#ifndef _CHIP_BLE_BLE_H
#error "Please include <ble/Ble.h> instead!"
#endif

#include <cstdint>

#include <lib/core/CHIPEncoding.h>

namespace chip {
namespace Ble {

/**
 * chip data block types that may appear with chip BLE service advertisement data.
 */
enum chipBLEServiceDataType
{
    kchipBLEServiceDataType_DeviceIdentificationInfo = 0x01,
    kchipBLEServiceDataType_TokenIdentificationInfo  = 0x02,
};

/**
 * chip BLE Device Identification Information Block
 *
 * Defines the over-the-air encoded format of the device identification information block that appears
 * within chip BLE service advertisement data.
 */
// TODO: Support Network Recovery service data block
struct ChipBLEDeviceIdentificationInfo
{
    constexpr static uint16_t kDiscriminatorMask            = 0xfff;
    constexpr static uint8_t kAdditionalDataFlagMask        = 0x1;
    constexpr static uint8_t kExtendedAnnouncementFlagMask  = 0x2;
    constexpr static uint8_t kAdvertisementVersionMask      = 0xf0;
    constexpr static uint8_t kAdvertisementVersionShiftBits = 4u;

    uint8_t OpCode;
    // DeviceDiscriminatorAndAdvVersion[0] contains the low 8 bits of the 12-bit discriminator.
    // DeviceDiscriminatorAndAdvVersion[1] contains the high 8 bits of the 12-bit discriminator in its low 4 bits and
    // the 4 bits of the advertisement version in its high 4 bits.
    uint8_t DeviceDiscriminatorAndAdvVersion[2];
    uint8_t DeviceVendorId[2];
    uint8_t DeviceProductId[2];
    uint8_t AdditionalDataFlag;

    void Init() { memset(this, 0, sizeof(*this)); }

    uint16_t GetVendorId() const { return chip::Encoding::LittleEndian::Get16(DeviceVendorId); }

    void SetVendorId(uint16_t vendorId) { chip::Encoding::LittleEndian::Put16(DeviceVendorId, vendorId); }

    uint16_t GetProductId() const { return chip::Encoding::LittleEndian::Get16(DeviceProductId); }

    void SetProductId(uint16_t productId) { chip::Encoding::LittleEndian::Put16(DeviceProductId, productId); }

    uint8_t GetAdvertisementVersion() const
    {
        uint8_t advertisementVersion = static_cast<uint8_t>((DeviceDiscriminatorAndAdvVersion[1] & kAdvertisementVersionMask) >>
                                                            kAdvertisementVersionShiftBits);
        return advertisementVersion;
    }

    // Use only 4 bits to set advertisement version
    void SetAdvertisementVersion(uint8_t advertisementVersion)
    {
        // Advertisement Version is 4 bit long from 12th to 15th
        advertisementVersion =
            static_cast<uint8_t>((advertisementVersion << kAdvertisementVersionShiftBits) & kAdvertisementVersionMask);
        DeviceDiscriminatorAndAdvVersion[1] =
            static_cast<uint8_t>((DeviceDiscriminatorAndAdvVersion[1] & ~kAdvertisementVersionMask) | advertisementVersion);
    }

    uint16_t GetDeviceDiscriminator() const
    {
        return chip::Encoding::LittleEndian::Get16(DeviceDiscriminatorAndAdvVersion) & kDiscriminatorMask;
    }

    void SetDeviceDiscriminator(uint16_t deviceDiscriminator)
    {
        // Discriminator is 12-bit long, so don't overwrite bits 12th through 15th
        auto advVersion     = static_cast<uint16_t>(DeviceDiscriminatorAndAdvVersion[1] << 8u & ~kDiscriminatorMask);
        deviceDiscriminator = static_cast<uint16_t>(advVersion | (deviceDiscriminator & kDiscriminatorMask));
        chip::Encoding::LittleEndian::Put16(DeviceDiscriminatorAndAdvVersion, deviceDiscriminator);
    }

    uint8_t GetAdditionalDataFlag() const { return (AdditionalDataFlag & kAdditionalDataFlagMask); }

    void SetAdditionalDataFlag(bool flag)
    {
        if (flag)
        {
            AdditionalDataFlag |= kAdditionalDataFlagMask;
        }
        else
        {
            AdditionalDataFlag &= static_cast<uint8_t>(~kAdditionalDataFlagMask);
        }
    }

    void SetExtendedAnnouncementFlag(bool flag)
    {
        if (flag)
        {
            AdditionalDataFlag |= kExtendedAnnouncementFlagMask;
        }
        else
        {
            AdditionalDataFlag &= static_cast<uint8_t>(~kExtendedAnnouncementFlagMask);
        }
    }

} __attribute__((packed));

/**
 * chip BLE Device Proximity Ranging Identification Information Block
 *
 * Defines the over-the-air encoded format of the proximity ranging identification
 * information block that appears within chip BLE service advertisement data.
 * Total size: 21 bytes.
 */
struct ChipBLEProximityRangingIdentificationInfo
{
    /**
     * OpCode for Proximity Ranging BLE advertisement.
     * Note: Shares value 0x02 with kchipBLEServiceDataType_TokenIdentificationInfo.
     * Proximity Ranging payloads are distinguished by their unique struct layout (21 bytes).
     */
    constexpr static uint8_t kOpCode = 0x02;

    constexpr static uint8_t kAdvertisementVersionMask      = 0xf0;
    constexpr static uint8_t kAdvertisementVersionShiftBits = 4u;

    uint8_t OpCode;                    // Byte 0: 0x02 = Proximity Ranging
    uint8_t AdvVersionAndReserved;     // Byte 1: Bits[7:4] = Adv version, Bits[3:0] = Reserved
    uint8_t MsgCounter[2];             // Bytes 2-3: 16-bit Message Counter (big-endian)
    uint8_t ObfuscatedBLEDeviceId[16]; // Bytes 4-19: HMAC-SHA256 obfuscated BLEDeviceId
    int8_t TxPower;                    // Byte 20: Tx Power

    void Init()
    {
        memset(this, 0, sizeof(*this));
        OpCode = kOpCode;
    }

    uint8_t GetAdvVersion() const
    {
        return static_cast<uint8_t>((AdvVersionAndReserved & kAdvertisementVersionMask) >> kAdvertisementVersionShiftBits);
    }

    void SetAdvVersion(uint8_t version)
    {
        AdvVersionAndReserved = static_cast<uint8_t>((AdvVersionAndReserved & ~kAdvertisementVersionMask) |
                                                     ((version << kAdvertisementVersionShiftBits) & kAdvertisementVersionMask));
    }

    uint16_t GetMsgCounter() const { return chip::Encoding::BigEndian::Get16(MsgCounter); }

    void SetMsgCounter(uint16_t counter) { chip::Encoding::BigEndian::Put16(MsgCounter, counter); }

    int8_t GetTxPower() const { return TxPower; }

    void SetTxPower(int8_t txPower) { TxPower = txPower; }

    const uint8_t * GetObfuscatedBLEDeviceId() const { return ObfuscatedBLEDeviceId; }

    void SetObfuscatedBLEDeviceId(const uint8_t * id)
    {
        if (id == nullptr)
        {
            return;
        }
        memcpy(ObfuscatedBLEDeviceId, id, sizeof(ObfuscatedBLEDeviceId));
    }

} __attribute__((packed));

static_assert(sizeof(ChipBLEProximityRangingIdentificationInfo) == 21,
              "Proximity Ranging identification info must be exactly 21 bytes");

} /* namespace Ble */
} /* namespace chip */