BlueZ-Official Linux Bluetooth protocol stack
Android 4.2之前，Google一直使用的是Linux官方蓝牙协议栈BlueZ。BlueZ实际上是由高通公司在2001年5月基于GPL协议发布的一个开源项目，做为Linux 2.4.6内核的官方蓝牙协议栈。随着Android设备的流行，BlueZ也得到了极大的完善和扩展。例如Android 4.1中BlueZ的版本升级为4.93，它支持蓝牙核心规范4.0，并实现了绝大部分的Profiles。
BlueZ provides support for the core Bluetooth layers and protocols. It is flexible, efficient and uses a modular implementation. It has many interesting features:
- Complete modular implementation
- Symmetric multi processing safe
- Multithreaded data processing
- Support for multiple Bluetooth devices
- Real hardware abstraction
- Standard socket interface to all layers
- Device and service level security support
Currently BlueZ consists of many separate modules:
- Bluetooth kernel subsystem core
- L2CAP and SCO audio kernel layers
- RFCOMM, BNEP, CMTP and HIDP kernel implementations
- HCI UART, USB, PCMCIA and virtual device drivers
- General Bluetooth and SDP libraries and daemons
- Configuration and testing utilities
- Protocol decoding and analysis tools
The current set of supported profiles is available here.