Blackrock User-Mode Bluetooth LE Library

A cross-platform user-mode BLE stack implementation starting from the USB transport layer via libusb.

Project status: Under active development. Tested on Windows and Linux. Not accepting external contributions at this time. The library implements all components for a BLE GATT server (peripheral role) and LE Secure Connections pairing. Minimum supported Bluetooth version is 5.0. All APIs are subject to change prior to v1.0.

Reference documents:

• Bluetooth Core Specification v5.4 (LE Core Configuration as defined in [Vol 0] Part B, Section 4.4)
• Core Specification Supplement v11
• Assigned Numbers
• GATT Specification Supplement

Profiles and services:

• Battery Service
• Device Information Service
• HID over GATT Profile

Example Server

The server example brings up a demo GATT server to test controller functionality.

Listing available Bluetooth controllers

$ cargo run --example server
Available controllers (pass 'ID <VID>:<PID>' to '--vid' and '--pid' options):
Bus 002 Device 012: ID 7392:c611
Bus 002 Device 003: ID 8087:0033

Running the server

• Linux users need to either configure udev permissions or run the example binary via sudo to give libusb device write access to the USB device.
• Windows users need to follow driver installation instructions from the section below.

Look for "Burble" Bluetooth device on the client. You can use nRF Connect for Mobile to get more details about the server advertisements and GATT services.

Some clients may not support extended LE advertising. Use the --legacy option to switch to legacy advertising PDUs.

$ RUST_LOG=info cargo run --example server -- --vid 7392 --pid c611
 INFO burble::host::usb::libusb: libusb version: 1.0.26.11724
 INFO burble::host::usb::libusb: Using WinUSB backend
 INFO server: Local version: LocalVersion { hci_version: V5_1, hci_subversion: 11, lmp_version: V5_1, company_id: CompanyId(0x005D => "Realtek Semiconductor Corporation"), lmp_subversion: 34657 }
 INFO server: Device address: Public(08:BE:AC:2E:0D:EE)
 INFO burble::gatt::schema: GATT schema:
 INFO burble::gatt::schema: [0x0001] GenericAccess <0x1800>
 INFO burble::gatt::schema: [0x0002] |__ DeviceName <0x2A00>
 INFO burble::gatt::schema: [0x0003] |   |__ [Value <0x2A00>]
 INFO burble::gatt::schema: [0x0004] |__ Appearance <0x2A01>
 INFO burble::gatt::schema: [0x0005]     |__ [Value <0x2A01>]
 INFO burble::gatt::schema: [0x0006] GenericAttribute <0x1801>
 INFO burble::gatt::schema: [0x0007] |__ ServiceChanged <0x2A05>
 INFO burble::gatt::schema: [0x0008] |   |__ [Value <0x2A05>]
 INFO burble::gatt::schema: [0x0009] |   |__ ClientCharacteristicConfiguration <0x2902>
 INFO burble::gatt::schema: [0x000A] |__ ClientSupportedFeatures <0x2B29>
 INFO burble::gatt::schema: [0x000B] |   |__ [Value <0x2B29>]
 INFO burble::gatt::schema: [0x000C] |__ DatabaseHash <0x2B2A>
 INFO burble::gatt::schema: [0x000D]     |__ [Value <0x2B2A>]
 INFO burble::gatt::schema: [0x000E] (Secondary) Battery <0x180F>
 INFO burble::gatt::schema: [0x000F] |__ BatteryLevel <0x2A19>
 INFO burble::gatt::schema: [0x0010]     |__ [Value <0x2A19>]
 INFO burble::gatt::schema: [0x0011] Glucose <0x1808>
 INFO burble::gatt::schema: [0x0012] |__ [Include 0x000E..=0x0010]
 INFO burble::gatt::schema: [0x0013] |__ GlucoseMeasurement <0x2A18>
 INFO burble::gatt::schema: [0x0014]     |__ [Value <0x2A18>]
 INFO burble::gatt::schema: [0x0015]     |__ ClientCharacteristicConfiguration <0x2902>
 INFO burble::gatt::schema: [0x0016]     |__ CharacteristicExtendedProperties <0x2900>

Windows

Either use Zadig to install the WinUSB driver for a specific Bluetooth device, or install UsbDk, which has some known issues, but doesn't require changing device drivers. See libusb Windows wiki page for more info.

UsbDk Known Issues

Hanging libusb_open

If a redirected device is not closed on exit (e.g. after a crash), subsequent attempts to open it may cause the process to hang for about two minutes, followed by a "Redirector startup failed" libusb error message. See daynix/UsbDk#105.

WDF_VIOLATION BSOD

A WDF_VIOLATION BSOD may be caused by having multiple multiple power policy owners enabled for the Bluetooth USB device. There are two workarounds:

1. Disable the device in the Device Manager.
2. Uncheck the option to "Allow the computer to turn off this device to save power" in Device Properties -> Power Management tab.

Tested Controllers

Below is a list of Bluetooth controllers that have been tested with this library.

Server

Client

Legal

Copyright 2023 Blackrock Neurotech. Licensed under the Mozilla Public License 2.0.

This is not an officially supported Blackrock Neurotech product.