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Networking

Enabling Networking

Networking is enabled by selecting the network laze module. When enabled, a network link is automatically selected among the ones available on the target board, currently preferring Wi-Fi networking. Overriding this default selection is possible by explicitly selecting the desired network link module.

Ariel OS currently supports two different networking links: Ethernet-over-USB (aka CDC-NCM) and Wi-Fi. Boards may support both of them, only one of them, or none of them. However, currently the network stack supports at most one interface.

Which link layer is used for networking is selected at compile time, through laze modules.

  • usb-ethernet: Selects Ethernet-over-USB.
  • wifi-cyw43: Selects Wi-Fi using the CYW43 chip along an RP2040 or RP235x MCU (e.g., on the Raspberry Pi Pico W or Pico 2 W).
  • wifi-esp: Selects Wi-Fi on an ESP32 MCU.

Network Credentials

For Wi-Fi, the network credentials have to be supplied via environment variables:

CONFIG_WIFI_NETWORK=<ssid> CONFIG_WIFI_PASSWORD=<pwd> laze build ...

Network Configuration

IPv4

Support for IPv4 is enabled by default. When unneeded, it can be disabled by disabling the ipv4 laze module.

DHCP is used by default for IPv4 network configuration, including for address allocation. This is enabled by the network-config-ipv4-dhcp laze module, selected by default for IPv4.

In order to provide a static configuration instead, select the network-config-ipv4-static laze module, which will take precedence. The configuration can be customized with the following environment variables:

VariableDefault
CONFIG_NET_IPV4_STATIC_ADDRESS10.42.0.61
CONFIG_NET_IPV4_STATIC_CIDR_PREFIX_LEN24
CONFIG_NET_IPV4_STATIC_GATEWAY_ADDRESS10.42.0.1

IPv6

Support for IPv6 is not currently enabled by default, but can be enabled by selecting the ipv6 laze module. IPv4 and IPv6 can both be enabled at the same time.

IPv6 currently only supports static configuration, which is therefore enabled by default; it can also be explicitly selected with the network-config-ipv6-static laze module.

The configuration must be customized with the following environment variables:

VariableDefault
CONFIG_NET_IPV6_STATIC_ADDRESSNo default, but mandatory
CONFIG_NET_IPV6_STATIC_CIDR_PREFIX_LEN64
CONFIG_NET_IPV6_STATIC_GATEWAY_ADDRESSNo default, but mandatory

Note

Non-static IPv6 address allocation will be supported in the future.

Support for Network Protocols

Support for various network protocols can be enabled through Cargo features listed in the documentation. Most of these use embassy_net, which should be used through the ariel_os::reexports::embassy_net re-export.

Using the Network Stack

A network stack handle can then be obtained using ariel_os::net::network_stack().

See the examples for details.

Host Setup

Static IPv4 Address Configuration

When using a device with a static IPv4 address, the host computer can be configured as follows (where host_address is an IP address configured as gateway for the device):

# ip address add <host_address>/24 dev <interface>
# ip link set up dev <interface>

To verify that the address has indeed be added, you can use:

ip address show dev <interface>

Replace <interface> with the name of the used network interface. To find out the name of your interface you can use a command such as ip address.

Ethernet-over-USB

For Ethernet-over-USB, ensure that, in addition to the USB cable used for flashing and debugging, the user USB port is also connected to the host computer with a second cable.