wpantund, Userspace WPAN Network Daemon
wpantund is a user-space network interface driver/daemon that
provides a native IPv6 network interface to a low-power wireless
Network Co-Processor (or NCP). It was written and developed by
Nest Labs to make supporting Thread
connectivity on Unix-like operating systems more straightforward.
wpantund is designed to marshall all access to the NCP, ensuring
that it always remains in a consistent and well-defined state.
This is not an official Google product.
Feature and Architecture Summary
- ... a native IPv6 interface to an NCP.
- ... a command line interface (
wpanctl) for managing and configuring the NCP.
- ... a DBus API for managing and configuring the NCP.
- ... a way to reliably manage the power state of the NCP.
- ... a uniform mechanism for handling NCP firmware updates.
The architecture and design of
wpantund has been motivated by the
following design goals (in no specific order):
- Portability across Unix-like operating systems (currently supports Linux. BSD support should be fairly trivial to add)
- Require few runtime dependencies (DBus, with boost needed when building)
- Single-threaded architecture, with heavy use of asynchronous I/O
- Power efficiency (0% CPU usage when idle)
- Allow management interface to be used by multiple independent applications simultaneously
- Allow multiple instances of
wpantundto gracefully co-exist on a single machine
- Modular, plugin-based architecture (all details for communicating with a specific NCP stack are implemented as plugins)
Note that Windows is not currently supported, but patches are welcome.
The following NCP plugins are provided:
src/ncp-spinel: Supports NCPs that communicate using the Spinel NCP Protocol, used by NCPs running OpenThread
src/ncp-dummy: A dummy NCP plug-in implementation meant to be the starting point for implementing new NCP plug-ins
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.
wpantund is conceptually similar in purpose to the point-to-point
pppd, commonly used on Unix platforms to provide network
connectivity via a dial-up modems) except that instead of communicating
with a dial-up modem,
wpantund is communicating with an NCP.
wpantund communicates with the NCP via an abstraction of a
asynchronous stream socket, which could be any of the following:
- A real serial port (UART) connected to the NCP (preferably with hardware flow control)
- The stdin and stdout from a subprocess (for supporting SPI interfaces using a translator program or debugging virtual stacks)
- A TCP socket (for debugging, not recommended for production)
Unlike a dial-up modem, NCPs often have a rich management interface
for performing operations, such as forming a network, joining a
network, scanning for nearby networks, etc. To perform these operations,
wpantund includes a command line utility called
Applications that need to directly configure the network interface can
also communicate directly with
wpantund using its DBus API.
To expose a native IPv6 network interface to the host operating
wpantund uses the
tun driver on Linux. On Linux, the
default name for the interface is
The behavior of
wpantund is determined by its configuration
parameters, which may be specified in a configuration file (typically
/etc/wpantund.conf) or at the command line. A typical configuration
file might look like that shown below. For a more thorough explanation
of available configuration parameters, see the included example.
# Try to name the network interface `wpan0`. # If not possible, a different name will be used. Config:TUN:InterfaceName "wpan0" # The pathname of the socket used to communicate # with the NCP. Config:NCP:SocketPath "/dev/ttyUSB0" # The name of the driver plugin to use. The chosen # plugin must support the NCP you are trying to use. Config:NCP:DriverName "spinel" # Drop root privileges after opening all sockets Config:Daemon:PrivDropToUser "nobody" # Use a CCA Threshold of -70db NCP:CCAThreshold "-70"
When up and running, you can use
wpanctl to check the status of the
interface and perform various management operations. For example, to
check the general status of an interface:
$ sudo wpanctl status wpan0 => [ "NCP:State" => "offline" "Daemon:Enabled" => true "NCP:Version" => "OPENTHREAD/g1651a47; May 23 2016 17:23:24" "Daemon:Version" => "0.07.00 (May 23 2016 12:58:54)" "Config:NCP:DriverName" => "spinel" "NCP:HardwareAddress" => [F1D92A82C8D8FE43] ]
Here we see that the NCP is in the
offline state along with a few
additional bits of information such as the version of the NCP and its
hardware address. From here we can easily form a new network:
$ sudo wpanctl form "wpantund-testnet" Forming WPAN "wpantund-testnet" as node type router Successfully formed! $
Now if we check the status, we will see more information:
$ sudo wpanctl status wpan0 => [ "NCP:State" => "associated" "Daemon:Enabled" => true "NCP:Version" => "OPENTHREAD/g1651a47; May 23 2016 17:23:24" "Daemon:Version" => "0.07.00 (May 23 2016 12:58:54)" "Config:NCP:DriverName" => "spinel" "NCP:HardwareAddress" => [F1D92A82C8D8FE43] "NCP:Channel" => 23 "Network:NodeType" => "leader" "Network:Name" => "wpantund-testnet" "Network:XPANID" => 0x09717AEF221F66FB "Network:PANID" => 0xBFCD "IPv6:LinkLocalAddress" => "fe80::f3d9:2a82:c8d8:fe43" "IPv6:MeshLocalAddress" => "fd09:717a:ef22::9a5d:5d1e:5527:5fc8" "IPv6:MeshLocalPrefix" => "fd09:717a:ef22::/64" ] $ ifconfig wpan0 wpan0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1280 inet6 fe80::f3d9:2a82:c8d8:fe43%wpan0 prefixlen 10 scopeid 0x15 inet6 fd09:717a:ef22::9a5d:5d1e:5527:5fc8 prefixlen 64
If compiled with
wpanctl supports an
convenient interactive console. All commands support online help: type
help to get a list of supported commands, or add
-h to a command to get
help with that specific command.
For simulation example Codelab please see: https://openthread.io/guides#try_openthread
Submit bugs and feature requests to issue tracker. We use the following mailing lists for discussion and announcements:
- Official Anouncements About
wpantundUser Discussion Group
wpantundDeveloper Discussion Group
Authors and Contributors
The following people have significantly contributed to the design
and development of
- Robert Quattlebaum
- Marcin Szczodrak
- Vaas Krishnamurthy
- Arjuna Siva
- Abtin Keshavarzian
If you would like to contribute to this project, please read CONTRIBUTING.md first.