go-bluetooth

Golang bluetooth client based on bluez DBus interfaces

See here for reference https://git.kernel.org/cgit/bluetooth/bluez.git/tree/doc

Features

The features implemented are

• Discovery
• Adapter support
• Client device support (see SensorTag example)
• GATT Service and characteristics interface
• Shell interfaces to rfkill, btmgmt, hciconfig, hcitool
• Handle systemd bluetooth.service unit
• Expose hci basic API
• Expose bluetooth services via bluez GATT API
• Basic pairing support
• Basic authentication support

Examples

The examples/ folder offer an overview of library

• agent a simple agent to support pairing
• btmgmt interface to CLI btmgmt
• discovery find devices around
• hci_updown HCI based communication example
• obex_push send file to a device
• sensortag_info Obtain data from a TI SensorTag
• sensortag_temperature Obtain temperature from a TI SensorTag
• service expose a bluetooth device with corresponding services
• show_miband_info show informations for MiBand2
• watch_changes register for notifications from a TI SensorTag

Note Ensure to install proper dbus rules on the system. For a dev setup use

sudo ln -s `pwd`/scripts/dbus-go-bluetooth-service.conf /etc/dbus-1/system.d/
sudo ln -s `pwd`/scripts/dbus-go-bluetooth-dev.conf /etc/dbus-1/system.d/

Setup

The library has been tested with

• golang 1.11.4 (starting from v1.6)
• bluez bluetooth v5.50 (starting from v5.43)

bluez upgrade

Bluez, the linux bluetooth implementation, has introduced GATT support from v5.43

Ensure you are using an up to date version with bluetoothd -v

See in scripts/ how to upgrade bluez

Development notes

Standard GATT characteristics descriptions can be found on https://www.bluetooth.com/specifications/gatt/

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

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

• Create a dbus profile

  ln -s `pwd`/scripts/dbus-dev.conf /etc/dbus-1/system.d/go-bluetooth.config

• Monitor activity

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

• View bluetoothd debug messages

  sudo service bluetooth stop && sudo bluetoothd -Edn P hostname

• Enable LE advertisement (to use a single pc, you will need 2 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

• https://git.kernel.org/cgit/bluetooth/bluez.git/tree/doc
• https://www.bluetooth.com/specifications/gatt/services
• http://events.linuxfoundation.org/sites/events/files/slides/Bluetooth%20on%20Modern%20Linux_0.pdf
• https://github.com/nettlep/gobbledegook

License

MIT License