go-bluetooth

Go bluetooth API for Linux-based Bluez DBus interface.

Features

The library is a wrapper to the Bluez DBus API and some high level API to ease the interaction.

High level features supported:

• Client code generation from bluez documentation
• Shell wrappers for rfkill, btmgmt, hciconfig, hcitool
• An hci socket basic API (inspired by go-ble/ble)
• Expose bluetooth service from go code [unstable]
• Pairing and authentication support (via agent)
• Beaconing send & receive (iBeacon and Eddystone)

Running examples

Examples are available in _examples folder.

cd _examples
go run main.go
# print available example commands
# Example discovery
go run main.go discovery

Development setup

1. Clone the repository

git clone https://github.com/muka/go-bluetooth.git

1. Retrieve the bluetooth API and generate GO code

make bluez/init bluez/checkout gen/clean gen/run

Code generation

The code structure follow this pattern:

• ./api contains wrappers for the DBus Api
• ./bluez contains the actual implementation, generated from the bluez documentation

Use make gen to re-generate go sources. There is also a commodity bluez JSON file available in the root folder for reference.

Generated code has gen_ prefix. If an API file exists with the same filename but without the prefix, generation will be skipped for that API.

DBus configuration setup

In order to interact with DBus, propert configurations must be installed in the system. For a development setup, the repository provides example configurations.

  cd <go-bluetooth path>
  # install dbus permissions configuration, may require a system restart
  make dev/dbus/install
  # Add bluetooth group to own the DBus service
  sudo addgroup bluetooth || true
  sudo adduser `id -nu` bluetooth

Requirements

The library is tested with

• golang 1.14.1
• bluez bluetooth v5.50, v5.54

Development notes

• Inspect a service ObjectManager

• Retrieve char properties

  dbus-send --system --print-reply --dest=go.bluetooth /hci0/apps/0/service000003e8/char0  org.freedesktop.DBus.Properties.GetAll string:org.bluez.GattCharacteristic1
  

• Give access to hciconfig to any user and avoid sudo (may have security implications)

  sudo setcap 'cap_net_raw,cap_net_admin+eip' `which hciconfig`
  

• Monitor Bluetooth activity

  sudo btmon

• Monitor DBus activity

  sudo dbus-monitor --system "type=error"

• Start bluetoothd with experimental features and verbose debug messages make bluetoothd

• Enable LE advertisement (on a single pc ensure to use at least 2x bluetooth adapter)

    sudo btmgmt -i 0 power off
    sudo btmgmt -i 0 name "my go app"
    sudo btmgmt -i 0 le on    
    sudo btmgmt -i 0 connectable on
    sudo btmgmt -i 0 advertising on
    sudo btmgmt -i 0 power on
  

References

• Standard GATT characteristics descriptions
• bluez git
• GATT services specs
• A C++ implementation
• DBus specifications
• SensorTag specs

License

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.