![VintageNet Logo](assets/vintage_net.png)

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> **_NOTE:_**  If you've been using `vintage_net` `v0.6.x` or earlier, we split
> out network technology support out to separate libraries in `v0.7.0`. You'll
> need to add those libraries to your `mix` dependency list and rename some
> atoms.  Configurations stored on deployed devices will be automatically
> updated.  See the [v0.7.0 release
> notes](
> for details.

`VintageNet` is network configuration library built specifically for [Nerves
Project]( devices. It has the following features:

* Ethernet and WiFi support included. Extendible to other technologies
* Default configurations specified in your Application config
* Runtime updates to configurations are persisted and applied on next boot
  (configurations are obfuscated by default to hide WiFi passphrases)
* Simple subscription to network status change events
* Connect to multiple networks at a time and prioritize which interfaces are
  used (Ethernet over WiFi over cellular)
* Internet connection monitoring and failure detection
* Predictable network interface names

> **TL;DR:** Don't care about any of this and just want the string to copy/paste
> to set up networking? See the [VintageNet Cookbook](

The following network configurations are supported:

* [x] Wired Ethernet, IPv4 DHCP
* [x] Wired Ethernet, IPv4 static IP
* [x] WiFi password-less and WEP
* [x] WPA2 PSK and EAP
* [x] USB gadget mode Ethernet, IPv4 DHCP server to supply host IP address
* [x] Cellular networks (see
  [`vintage_net_qmi`]( and
  [`vintage_net_mobile`]( for details)
* [x] WiFi AP mode
* [ ] IPv6 - Partially supported. SLAAC configuration works.

`vintage_net` takes a different approach to networking from `nerves_network`.
Its focus is on building and applying network configurations. Where
`nerves_network` provided configurable state machines, `vintage_net` turns
human-readable configurations into everything from configuration files and calls
to [`ip`]( to starting up networking `GenServers`
and routing table updates. This makes it easier to add support for new network
technologies and features. While Elixir and Erlang were great to implement
network protocols in, it was frequently more practical to reuse embedded Linux
implementations. Importantly, though, `vintage_net` monitors Linux daemons under
its OTP supervision tree so failures on both the "C" and Elixir sides propagate
in the expected ways.

Another important difference is that `VintageNet` doesn't attempt to make
incremental modifications to configurations. It completely tears down an
interface's connection and then brings up new configurations in a fresh state.
Network reconfiguration is assumed to be an infrequent event so while this can
cause a hiccup in the network connectivity, it removes state machine code that
made `nerves_network` hard to maintain.

## Installation

First, if you're modifying an existing project, you will need to remove
`nerves_network` and `nerves_init_gadget`. `vintage_net` doesn't work with
either of them. You'll get an error if any project references those packages.

There are two routes to integrating `vintage_net`:

1. Use [nerves_pack]( `nerves_pack` is like
   `nerves_init_gadget`, but for `vintage_net`.
2. Copy and paste from the
   [Nerves hello WiFi example](

The next step is to make sure that your Nerves system is compatible. The
official Nerves systems released after 12/11/2019 work without modification. If
rolling your own Nerves port, you will need the following Linux kernel options


Then make sure that you have the following Busybox options enabled:

* `CONFIG_IFCONFIG=y` - `ifconfig` ifconfig
* `CONFIG_UDHCPC=y` - `udhcpc` DHCP Client
* `CONFIG_UDHCPD=y` - `udhcpd` DHCP Server (optional)

Finally, you'll need to choose what network connection technologies that you
want available in your firmware. If using `nerves_pack`, you'll get support for
wired Ethernet, WiFi, and USB gadget networking automatically. Otherwise, add
one or more of the following to your dependency list:

* [`vintage_net_ethernet`]( - Standard wired Ethernet
* [`vintage_net_wifi`]( - Client configurations for 802.11 WiFi
* [`vintage_net_direct`]( - Direct connections like those used for USB gadget
* [`vintage_net_qmi`]( - Support USB-connected cellular modems
* [`vintage_net_mobile`]( - Support UART-connected cellular modems

## Configuration

`VintageNet` has many application configuration keys. Most defaults are fine. At
a minimum, you'll want to specify a default configuration and default regulatory
domain if using WiFi. In your main `config.exs`, add the following:

config :vintage_net,
  regulatory_domain: "US",
  config: [
    {"eth0", %{type: VintageNetEthernet, ipv4: %{method: :dhcp}}},
    {"wlan0", %{type: VintageNetWiFi}}

This sets the regulatory domain to the US (set to your [ISO 3166-1 alpha-2
country code]( This code is
passed on to the drivers for WiFi and other wireless networking technologies so
that they comply with local regulations. If you need a global default, set to
"00" or don't set at all.  Unfortunately, this may mean that an access point
isn't visible if it is running on a frequency that's allowed in your country,
but not globally.

The `config` section is a list of network configurations. The one shown above
configures DHCP on wired Ethernet and minimally starts up a WiFi LAN so that
it's possible to scan for networks. The typical setup is to provide generic
defaults here. Static IP addresses, WiFi SSIDs and credentials are more
appropriately configured at run-time. `VintageNet` persists configurations too.
Details on network configuration are described later.

The following table describes the other application config keys.

Key                | Description
 ----------------- | ---------------------------
config             | A list of default network configurations
tmpdir             | Path to a temporary directory for VintageNet
udhcpc_handler     | Module for handling notifications from `udhcpc`
resolvconf         | Path to `/etc/resolv.conf`
persistence        | Module for persisting network configurations
persistence_dir    | Path to a directory for storing persisted configurations
persistence_secret | A 16-byte secret or an MFA for getting a secret
internet_host_list | IP address or hostnames and ports to try to connect to for checking Internet connectivity. Defaults to a list of large public DNS providers. E.g., `[{{1, 1, 1, 1}, 53}]`.
regulatory_domain  | ISO 3166-1 alpha-2 country (`00` for global, `US`, etc.)
additional_name_servers     | List of DNS servers to be used in addition to any supplied by an interface. E.g., `[{1, 1, 1, 1}, {8, 8, 8, 8}]`
route_metric_fun   | Customize how network interfaces are prioritized. See `VintageNet.Route.DefaultMetric.compute_metric/2`

## Network interface configuration

`VintageNet` supports several network technologies out of the box and
third-party libraries can provide more via the `VintageNet.Technology`

Configurations are Elixir maps. These are specified in three places:

1. The `vintage_net` application config (e.g., your `config.exs`)
2. Locally saved configuration (see the `VintageNet.Persistence` behaviour for
   replacing the default)
3. Calling `VintageNet.configure/2` to change the configuration at run-time

When `vintage_net` starts, it applies saved configurations first and if any
thing is wrong with those configs, it reverts to the application config. A good
practice is to have safe defaults for all network interfaces in the application

The only required key in the configuration maps is `:type`. All other keys
follow from the type. `:type` should be set to a module that implements the
`VintageNet.Technology` behaviour. The following are common technologies:

* [`VintageNetEthernet`]( - Standard wired Ethernet
* [`VintageNetWiFi`]( - Client configurations for 802.11 WiFi
* [`VintageNetDirect`]( - Direct connections like those used for USB gadget
* `VintageNet.Technology.Null` - An empty configuration useful for turning off a

See the links above for specific documentation.

## Persistence

By default, VintageNet stores network configuration to disk. If you are
migrating from `nerves_network` you may already have a persistence
implementation. To disable the default persistence, configure `vintage_net` as

config :vintage_net,
  persistence: VintageNet.Persistence.Null

## Debugging

Debugging networking issues is not fun. When you're starting out with
`vintage_net`, it is highly recommended to connect to your target using a method
that doesn't require networking to work. This could be a UART connection to an
IEx console on a Nerves device or maybe just hooking up a keyboard and monitor.

If having trouble, first check `` to verify the configuration
and connection status:

VintageNet 0.3.0

All interfaces:       ["eth0", "lo", "tap0", "wlan0"]
Available interfaces: ["eth0", "wlan0"]

Interface eth0
  Type: VintageNetEthernet
  Present: true
  State: :configured
  Connection: :internet
    %{ipv4: %{method: :dhcp}, type: VintageNetEthernet}

Interface wlan0
  Type: VintageNetWiFi
  Present: true
  State: :configured
  Connection: :internet
      ipv4: %{method: :dhcp},
      type: VintageNetWiFi,
      wifi: %{
        key_mgmt: :wpa_psk,
        mode: :infrastructure,
        psk: "******",
        ssid: "MyLAN"

If you're using [Toolshed](, try running
the following:

iex> ifconfig
lo: flags=[:up, :loopback, :running]
    inet  netmask
    inet ::1  netmask ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff
    hwaddr 00:00:00:00:00:00

eth0: flags=[:up, :broadcast, :running, :multicast]
    inet  netmask  broadcast
    inet fe80::6264:5ff:fee1:4045  netmask ffff:ffff:ffff:ffff::
    hwaddr 60:64:05:e1:40:45

wlan0: flags=[:up, :broadcast, :running, :multicast]
    inet  netmask  broadcast
    inet fe80::20c:e7ff:fe11:3d46  netmask ffff:ffff:ffff:ffff::
    hwaddr 00:0c:e7:11:3d:46

Or ping:

iex> ping ""
Press enter to stop
Response from ( time=48.87ms
Response from ( time=42.856ms
Response from ( time=43.097ms

You can also specify an interface to use with `ping`:

iex> ping "", ifname: "wlan0"
Press enter to stop
Response from ( time=57.817ms
Response from ( time=46.796ms

iex> ping "", ifname: "eth0"
Press enter to stop
Response from ( time=47.923ms
Response from ( time=48.688ms

If it looks like nothing is working, check the logs. On Nerves devices, this
is frequently done by calling `` or `RingLogger.attach`.

At a last resort, please open a GitHub issue. We would be glad to help. We only
have one ask and that is that you get us started with an improvement to our
documentation or code so that the next person to run into the issue will have an
easier time. Thanks!

## Properties

`VintageNet` maintains a key/value store for retrieving information on
networking information:

iex> VintageNet.get(["interface", "eth0", "connection"])

iex> VintageNet.get_by_prefix([])
  {["interface", "eth0", "connection"], :internet},
  {["interface", "eth0", "state"], :configured},
  {["interface", "eth0", "type"], VintageNetEthernet},
  {["interface", "wlan0", "connection"], :internet},
  {["interface", "wlan0", "state"], :configured},
  {["interface", "wlan0", "type"], VintageNetWiFi}

You can also subscribe to keys and receive a message every time it or one its
child keys changes:

iex> VintageNet.subscribe(["interface", "eth0"])

iex> flush
{VintageNet, ["interface", "eth0", "state"], :configuring, :configured, %{old_timestamp: 123456, new_timestamp: 124456}}

The message format is `{VintageNet, name, old_value, new_value, metadata}`

Metadata fields include at least the following:

* `:old_timestamp` - the timestamp for when the property first had the `old_value`
* `:new_timestamp` - the timestamp when the property changed from the `old_value` to the `new_value`

Timestamps are all captured by calling `System.monotonic_time/0` so they're in `:native` time units.

Use `System.convert_time_unit/3` to convert to the usual time units.

### Global properties

Property               | Values           | Description
 --------------------- | ---------------- | -----------
`available_interfaces` | `[eth0, ...]`    | Currently available network interfaces in priority order. E.g., the first one is used by default
`connection`           | `:disconnected`, `:lan`, `:internet` | The overall network connection status. This is the best status of all interfaces.

### Common network interface properties

All network interface properties can be found under `["interface", ifname]` in
the `PropertyTable`.  The following table lists out properties common to all

Property      | Values              | Description
 ------------ | ------------------- | -----------
`type`        | `VintageNetEthernet`, etc. | The type of the interface
`config`      | `%{...}`            | The configuration for this interface
`state`       | `:configured`, `:configuring`, etc. | The state of the interface from `VintageNet`'s point of view.
`hw_path`     | `"/devices/platform/ocp/4a100000.ethernet"` | This is how Linux internally views the connections going to the interface.
`connection`  | `:disconnected`, `:lan`, `:internet` | This provides a determination of the Internet connection status
`lower_up`    | `true` or `false`   | This indicates whether the physical layer is "up". E.g., a cable is connected or WiFi associated
`mac_address` | "11:22:33:44:55:66" | The interface's MAC address as a string
`addresses`   | [address_info]      | This is a list of all of the addresses assigned to this interface

Specific types of interfaces provide more parameters.

### Predictable network interface names

When using more than one of the same type of interface, it's possible for Linux
to reorder their naming. For example, if you have two USB WiFi adapters, one
will be named `wlan0` and the other `wlan1`. Which one is first depends on
things like when the adapter is found and when kernel modules are loaded.  This
can vary between boots and cause a lot of confusion.

The solution is to rename network interfaces based on characteristics of the
interface - such as how it's connected. Then application software refers to the
new name rather than names like `wlan0`.  This is a common problem, and
VintageNet provides support for automatically renaming network interfaces.

If you're used to `systemd`'s approach to naming interfaces, be aware that
VintageNet's approach is different: `systemd` has an
for generating names (e.g., `enp4s0`) automatically. VintageNet requires you to
provide the names to use (e.q., `internet0`, `lan0`, etc.) and how they map to
hardware. If VintageNet is confronted with a network interface that is connected
in a way that it doesn't know about, it will do nothing.

> IMPORTANT: Do not mix and match predictable interface names and
> non-predictable interface names (`wlan*`, `eth*`, `usb*`, `wwan*`). It is
> confusing and VintageNet will fight you.

Before switching to predictable names, find out how your network interfaces are
connected. For example, this device has an Ethernet interface and two USB WiFi

iex> VintageNet.match(["interface", :_, "hw_path"])
  {["interface", "eth0", "hw_path"], "/devices/platform/ocp/4a100000.ethernet"},
  {["interface", "lo", "hw_path"], "/devices/virtual"},
  {["interface", "wlan0", "hw_path"], "/devices/platform/ocp/47400000.usb/47401c00.usb/musb-hdrc.1/usb2/2-1/2-1:1.0"},
  {["interface", "wlan1", "hw_path"], "/devices/platform/ocp/47400000.usb/47401400.usb/musb-hdrc.0/usb1/1-1/1-1:1.4"}

Now update your `config.exs` with the mappings with the `:ifnames` key. Be sure
to also update the default configuration with the new interface names.
Continuing the example, imagine that one WiFi adapter supports 802.11 meshing
and it's guaranteed to be in one USB port on the device. The other USB port can
have any of a few types of USB WiFi modules. We need to use predictable naming
in this case so that meshing is only setup on the adapter that supports it.

config :vintage_net,
  ifnames: [
      hw_path: "/devices/platform/ocp/4a100000.ethernet",
      ifname: "ethernet0"
      hw_path: "/devices/platform/ocp/47400000.usb/47401c00.usb/musb-hdrc.1/usb2/2-1/2-1:1.0",
      ifname: "primary_wifi"
      hw_path: "/devices/platform/ocp/47400000.usb/47401400.usb/musb-hdrc.0/usb1/1-1/1-1:1.4",
      ifname: "mesh_wifi"
  config: [
    {"ethernet0", %{type: VintageNetEthernet}},
    {"primary_wifi", %{type: VintageNetWiFi}},
    {"mesh_wifi", %{type: VintageNetWiFi}}

> IMPORTANT: VintageNet has rules about renaming interfaces to prevent confusing
> errors. Below is a list of reasons it *will not* rename an interface

* `hw_path` matches `/devices/virtual` (such as `lo0`, `ppp0` etc.)
* A second interface's `hw_path` matches an interface that has already been
  renamed. This *should* never happen.

## Internet connectivity checks

VintageNet can check whether a network interface can reach the Internet. This
has a few uses:

1. Selecting which network interface is used when a device has more than one. A
   common example is a device with a backup cellular connection.
2. Automatically recovering a network interface that has lost connectivity. Some
   times bouncing the network interface actually works, so doing this
   automatically can sometimes revive a remote device.
3. Letting the application know the status of the network connection to provide
   more helpful information about what's happening.

The logic for declaring that the Internet is available is:

1. Is there a TCP socket in use on the network interface that has sent and
   received data from a host that's not on the same subnet? If yes, then the
   device is Internet-connected.
2. Get the list of Internet servers to check. See below for the list.
3. Resolve any domain names in the list. If DNS isn't working, remove them from
   the list.
4. Pick a random IP address from the remaining list and "ping" it. Technically,
   VintageNet tries to connect over TCP to a specified port, and if it either
   connects successfully or gets a port closed response, then the device is
5. Wait a bit and then go back to step 1.

The list of Internet servers to check is critically important. VintageNet uses
the `:internet_host_list` key in the application environment for this. The
default setting has many popular name servers in it. The idea being that if you
can't reach a name server, the Internet probably isn't going to work well.

If you are deploying to locations with locked down networks, you'll find that
the default setting to test name servers won't work. It is not uncommon to find
a network that blocks popular name servers like

The recommendation is to set the `:internet_host_list` to include your backend
server. If VintageNet can reach it, then presumably your application works and
having VintageNet declare the internet reachable via that network interface is

For example,

config :vintage_net,
  internet_host_list: [{"", 443}]

The use of the connectivity checker is specified by the technology. Both the
`VintageNetEthernet` and `VintageNetWiFi` use the internet connectivity checker.
This is selected by adding the `VintageNet.Connectivity.InternetChecker`
GenServer to the `:child_specs` configuration returned by the technology. E.g.,
`child_specs: [{VintageNet.Connectivity.InternetChecker, "eth0"}]`. Most users
do not need to be concerned about this.

## Power Management

Some devices require additional work to be done for them to become available.
Examples of this are:

1. Setting a GPIO to enable power to the module
2. Loading a Linux kernel module that is not automatically loaded via the
   default mechanisms
3. Running `usb_modeswitch` to change the USB interface to the appropriate state
4. Performing an initialization step such as loading firmware

Similarly, when the network interface is no longer being used, it can be nice to
undo any steps above.

This process is referred to as power management in VintageNet even though the
implementation may not actually affect power use. To use it, implement the
`VintageNet.PowerManager` behaviour and register the implementation in your

Additionally, VintageNet runs a watchdog-like service for network devices that
supply `VintageNet.PowerManager` implementations. If the watchdog is not pet
within the timeout period (user-specified and defaults to 60 seconds),
VintageNet powers the device off and and on. The VintageNet power management
code supports mandatory minimum on and off times to prevent damage to hardware
and also minimize pointless power cycling of hardware.

While many network devices are fairly reliable and powering off and on seems
unnecessary, it can save a trip to the field or a full device reboot.

`` shows the power management state for network interfaces that
are using this feature.