nerves-networking/vintage_net_ethernet

Ethernet networking for VintageNet

VintageNetEthernet adds support to VintageNet for wired Ethernet connections. It can be used for virtual Ethernet or for other non-wired Ethernet scenarios, but support is minimal. You may also be interested in VintageNetDirect or VintageNetWiFi.

Assuming that your device has Ethernet ports, all you need to do is add :vintage_net_ethernet to your mix dependencies like this:

def deps do
  [
    {:vintage_net_ethernet, "~> 0.7.0", targets: @all_targets}
  ]
end

Using

Wired Ethernet interfaces typically have names like "eth0", "eth1", etc. when using Nerves.

An example configuration for enabling an Ethernet interface that dynamically gets an IP address is:

config :vintage_net,
  config: [
    {"eth0",
     %{
       type: VintageNetEthernet,
       ipv4: %{
         method: :dhcp
       }
     }}
  ]

You can also set the configuration at runtime:

iex> VintageNet.configure("eth0", %{type: VintageNetEthernet, ipv4: %{method: :dhcp}})
:ok

Here's a static IP configuration:

iex> VintageNet.configure("eth0", %{
    type: VintageNetEthernet,
    ipv4: %{
      method: :static,
      address: "192.168.9.232",
      prefix_length: 24,
      gateway: "192.168.9.1",
      name_servers: ["1.1.1.1"]
    }
  })
:ok

In the above, IP addresses were passed as strings for convenience, but it's also possible to pass tuples like {192, 168, 9, 232} as is more typical in Elixir and Erlang. VintageNet internally works with tuples.

The following fields are supported:

• :method - Set to :dhcp, :static, or :disabled. If :static, then at least an IP address and mask need to be set. :disabled enables the interface and doesn't apply an IP configuration
• :address - the IP address for static IP addresses
• :prefix_length - the number of bits in the IP address to use for the subnet (e.g., 24)
• :netmask - either this or prefix_length is used to determine the subnet.
• :gateway - the default gateway for this interface (optional)
• :name_servers - a list of name servers for static configurations (optional)
• :domain - a search domain for DNS

Wired Ethernet connections are monitored for Internet connectivity if a default gateway is available. When internet-connected, they are preferred over all other network technologies even when the others provide default gateways.

Setting the MAC address

On some devices, you'll get a random Ethernet MAC address by default and need to read a real MAC address out of an EEPROM. VintageNet can help with this by calling a function to read the MAC address at the right time. You can also force a MAC address if a configuration if you want to allow users to change it on the fly.

Here's an example where the MAC address is set via a callback function:

   {"eth0",
      %{
        type: VintageNetEthernet,
        mac_address: {MyMacAddressReader, :read, []},
        ipv4: %{method: :dhcp}
      }}

MyMacAddress.read/0 is expected to return a string of the form "11:22:33:44:55:66". Any other return value or raising an exception will cause VintageNet to skip setting the MAC address.

Instead of supplying an MFArgs tuple, you can specify a string for the :mac_address key.

Properties

There are no wired Ethernet-specific properties. See vintage_net for the default set of properties for all interface types.