.. _networking:
Networking
==========
barebox has IPv4 networking support. Several protocols such as :ref:`DHCP
<command_dhcp>`, NFS and TFTP are supported.
Network configuration
---------------------
Lowlevel network device configuration
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Network devices are configured with a set of device specific variables:
+-------------------+--------------+----------------------------------------------------+
| name | type | |
+===================+==============+====================================================+
| <devname>.mode | enum | "dhcp": DHCP is used to get IP address and netmask |
| | | "static": Static IP setup described by variables |
| | | below |
| | | "disabled": Interface unused |
+-------------------+--------------+----------------------------------------------------+
| <devname>.ipaddr | ipv4 address | The IP address when using static configuration |
+-------------------+--------------+----------------------------------------------------+
| <devname>.netmask | ipv4 address | The netmask when using static configuration |
+-------------------+--------------+----------------------------------------------------+
| <devname>.gateway | ipv4 address | Alias for global.net.gateway. For |
| | | compatibility, do not use. |
+-------------------+--------------+----------------------------------------------------+
| <devname>.serverip| ipv4 address | Alias for global.net.server. For |
| | | compatibility, do not use. |
+-------------------+--------------+----------------------------------------------------+
| <devname>.ethaddr | MAC address | The MAC address of this device |
+-------------------+--------------+----------------------------------------------------+
Additionally there are some more variables that are not specific to a
device:
+------------------------------+--------------+------------------------------------------------+
| name | type | |
+==============================+==============+================================================+
| global.net.gateway | ipv4 host | The network gateway used when a host is not in |
| | | any directly visible subnet. May be set |
| | | automatically by DHCP. |
+------------------------------+--------------+------------------------------------------------+
| global.net.server | hostname or | The default server. If unspecified, may be set |
| | ipv4 address | by DHCP |
+------------------------------+--------------+------------------------------------------------+
| global.net.nameserver | ipv4 address | The DNS server used for resolving host names. |
| | | May be set by DHCP |
+------------------------------+--------------+------------------------------------------------+
| global.net.ifup_force_detect | boolean | Set to true if your network device is not |
| | | detected automatically during start (i.e. for |
| | | USB network adapters) |
+------------------------------+--------------+------------------------------------------------+
The first step for networking is configuring the network device. The network
device is usually ``eth0``. The current configuration can be viewed with the
:ref:`devinfo <command_devinfo>` command:
.. code-block:: sh
barebox:/ devinfo eth0
Parameters:
ethaddr: 00:1c:49:01:03:4b
ipaddr: 192.168.23.197
netmask: 255.255.0.0
[...]
The configuration can be changed on the command line with:
.. code-block:: sh
eth0.ipaddr=172.0.0.10
The :ref:`dhcp command <command_dhcp>` will change the settings based on the answer
from the DHCP server.
To make the network device settings persistent across reboots there is a nonvolatile
variable (nvvar) for each of the varariables above. The network device specific variables
are:
.. code-block:: sh
nv.dev.<devname>.mode
nv.dev.<devname>.ipaddr
nv.dev.<devname>.netmask
nv.dev.<devname>.ethaddr
The others are:
.. code-block:: sh
nv.net.gateway
nv.net.server
nv.net.nameserver
A typical simple network setting is to use DHCP. Provided the network interface is eth0
then this would configure the network device for DHCP:
.. code-block:: sh
nv dev.eth0.mode=dhcp
(In fact DHCP is the default, so the above is not necessary)
A static setup would look like:
.. code-block:: sh
nv dev.eth0.mode=static
nv dev.eth0.ipaddr=192.168.0.17
nv dev.eth0.netmask=255.255.0.0
nv net.server=192.168.0.1
The settings can be activated with the :ref:`ifup command <command_ifup>`:
.. code-block:: sh
ifup eth0
or:
.. code-block:: sh
ifup -a
'ifup -a' will activate all ethernet interfaces, also the ones on USB.
Network filesystems
-------------------
barebox supports NFS and TFTP both with commands (:ref:`nfs <command_nfs>` and
:ref:`tftp <command_tftp>`) and as filesystem implementations; see
:ref:`filesystems_nfs` and :ref:`filesystems_tftp` for more information. After
the network device has been brought up, a network filesystem can be mounted
with:
.. code-block:: sh
mount -t tftp 192.168.2.1 /mnt
or
.. code-block:: sh
mount -t nfs 192.168.2.1:/export none /mnt
**NOTE:** The execution of the mount command can often be hidden behind the
:ref:`automount command <command_automount>`, to make mounting transparent to
the user.
Network console
---------------
barebox has a UDP-based network console. If enabled in the config, you will see
something like this during startup::
registered netconsole as netconsole
By default the network console is disabled during runtime to prevent security
risks. It can be enabled using:
.. code-block:: sh
netconsole.ip=192.168.23.2
netconsole.active=ioe
This will send UDP packets to a PC with IP address 192.168.23.2 and port 6666.
The ``netconsole.active`` parameter consists of the fields "input" (i),
"output" (o) and "error" (e); if the fields are set, the respective channel is
activated on the network console.
On the PC side, the ``scripts/netconsole`` script can be used to remote control
barebox:
.. code-block:: sh
scripts/netconsole <board IP> 6666
The netconsole can be used just like any other console. Note, however, that the
simple console protocol is UDP based, so there is no guarantee about packet
loss.
