Adding Manufacturer specific data into Advertising data

[FTaluk]

Hi,
I am kind of new to C++ and Bluetooth. I have just started using your server. I have successfully implemented a basic NUS based chat application by modifying your server code and standalone app code. Thanks for all your effort.

But I need to add manufacturer specific data into the advertising data. I could not find any easy way until now to do this. With my limited understanding, I realized that I have to change things much deep into your codes (e.g. using add Advertising command of management-api instead of set advertising command). But the problem is that I am afraid of chaning things without having a complete grasp (which I don't have at the moment).

p.s. I found a python based example where they provide a seperate method just to set this data. But I need a C++ based solution.
Could you please help? Thanks in advance.

[FTaluk]

Hi,
I figured it out. Actually, I created a simple work-around. The setAdvertising() method Mgmt.cpp file has been modified. This method now disables the "setAdvertising" command and then uses "addAdvertising Command" to make use of a custom AD-Payload. I used only one instance, zero for all time related parameters, zero for all flags. I didn't use the scan response field. The whole raw-advertising data is provied as adv_data. This worked for me.

[stez-mind]

For those interested, I also did something similar as the FTaluk solution.

I'll have to think more how to include this in a way that's generic enough for making a PR but in the meanwhile, here's my implementation in Mgmt.cpp that calls addAdvertising adding one 128-bit service UUID and a 8 chars short name into the advertisement packet:

// Start advertising with custom data
// Advertisement packet will contain: flags, shortName, uuid
bool Mgmt::addAdvertising(std::string shortName, const uint8_t* uuid)
{
    constexpr size_t ADVERTISING_SHORTNAME_MAX_LEN = 8;
    constexpr size_t ADVERTISING_UUID_LEN = 16;
    constexpr size_t ADVERTISING_MAX_DATALEN = 2 + ADVERTISING_SHORTNAME_MAX_LEN + 2 + ADVERTISING_UUID_LEN;

    struct SRequest : HciAdapter::HciHeader
    {
        uint8_t  instance;
        uint32_t flags;
        uint16_t duration;
        uint16_t timeout;
        uint8_t  advDataLen;
        uint8_t  scanRspLen;
        uint8_t  data[ADVERTISING_MAX_DATALEN];
    } __attribute__((packed));

    SRequest request;
    request.code = Mgmt::EAddAdvertisingCommand;
    request.controllerId = controllerIndex;
    request.dataSize = sizeof(SRequest) - sizeof(HciAdapter::HciHeader);

    request.instance = 1u;
    request.flags = 3u; // Connectable && Discoverable, see Bluez/lib/mgmt.h
    request.duration = 0;
    request.timeout = 0;

    size_t shortNameEffectiveLen = std::min(ADVERTISING_SHORTNAME_MAX_LEN, shortName.length());
    request.advDataLen = ADVERTISING_MAX_DATALEN - (ADVERTISING_SHORTNAME_MAX_LEN - shortNameEffectiveLen);
    request.scanRspLen = 0;

    request.data[0] = static_cast<uint8_t>(ADVERTISING_UUID_LEN + 1);
    request.data[1] = 0x07; // Incomplete UUID list
    memcpy(&request.data[2], uuid, ADVERTISING_UUID_LEN);

    request.data[2+ADVERTISING_UUID_LEN] = static_cast<uint8_t>(1 + shortNameEffectiveLen);
    request.data[3+ADVERTISING_UUID_LEN] = 0x08;  // Set short name
    memcpy(&request.data[4+ADVERTISING_UUID_LEN], shortName.c_str(), shortNameEffectiveLen);

    if (!HciAdapter::getInstance().sendCommand(request))
    {
	Logger::warn(SSTR << "  + Failed to start advertising with UUID");
	return false;
    }

    return true;
}

[xuio]

@stez-mind can you give more detail about the usage of Mgmt::addAdvertising?
It is not working for me. You have to do Mgmt::setAdvertising(0) after, right?

[stez-mind]

Hi @xuio,
sorry it has been quite a long time since I worked on this.

I just checked my implementation and I was not calling explicitly Mgmt::setAdvertising(0) directly from the C++ sources but I remember that I was doing a few tasks separately with a script calling hcitool.

[xuio]

@stez-mind Thanks for answering!

Can you share the context in which you call Mgmt::addAdvertising(...). Thanks!