On 8/9/22 5:31 PM, Pali Rohár wrote:
> On Tuesday 09 August 2022 16:48:23 Sean Anderson wrote:
>> On 8/8/22 5:45 PM, Michal Suchánek wrote:
>> > On Mon, Aug 08, 2022 at 02:38:35PM -0700, Stephen Hemminger wrote:
>> >> On Mon, 8 Aug 2022 23:09:45 +0200
>> >> Michal Suchánek <msuchanek@xxxxxxx> wrote:
>> >>
>> >> > On Mon, Aug 08, 2022 at 03:57:55PM -0400, Sean Anderson wrote:
>> >> > > Hi Tim,
>> >> > >
>> >> > > On 8/8/22 3:18 PM, Tim Harvey wrote:
>> >> > > > Greetings,
>> >> > > >
>> >> > > > I'm trying to understand if there is any implication of 'ethernet<n>'
>> >> > > > aliases in Linux such as:
>> >> > > > aliases {
>> >> > > > ethernet0 = &eqos;
>> >> > > > ethernet1 = &fec;
>> >> > > > ethernet2 = &lan1;
>> >> > > > ethernet3 = &lan2;
>> >> > > > ethernet4 = &lan3;
>> >> > > > ethernet5 = &lan4;
>> >> > > > ethernet6 = &lan5;
>> >> > > > };
>> >> > > >
>> >> > > > I know U-Boot boards that use device-tree will use these aliases to
>> >> > > > name the devices in U-Boot such that the device with alias 'ethernet0'
>> >> > > > becomes eth0 and alias 'ethernet1' becomes eth1 but for Linux it
>> >> > > > appears that the naming of network devices that are embedded (ie SoC)
>> >> > > > vs enumerated (ie pci/usb) are always based on device registration
>> >> > > > order which for static drivers depends on Makefile linking order and
>> >> > > > has nothing to do with device-tree.
>> >> > > >
>> >> > > > Is there currently any way to control network device naming in Linux
>> >> > > > other than udev?
>> >> > >
>> >> > > You can also use systemd-networkd et al. (but that is the same kind of mechanism)
>> >> > >
>> >> > > > Does Linux use the ethernet<n> aliases for anything at all?
>> >> > >
>> >> > > No :l
>> >> >
>> >> > Maybe it's a great opportunity for porting biosdevname to DT based
>> >> > platforms ;-)
>> >>
>> >> Sorry, biosdevname was wrong way to do things.
>> >> Did you look at the internals, it was dumpster diving as root into BIOS.
>> >
>> > When it's BIOS what defines the names then you have to read them from
>> > the BIOS. Recently it was updated to use some sysfs file or whatver.
>> > It's not like you would use any of that code with DT, anyway.
>> >
>> >> Systemd-networkd does things in much more supportable manner using existing
>> >> sysfs API's.
>> >
>> > Which is a dumpster of systemd code, no thanks.
>> >
>> > I want my device naming independent of the init system, especially if
>> > it's systemd.
>>
>> Well, there's always nameif...
>>
>> That said, I have made [1] for people using systemd-networkd.
>>
>> --Sean
>>
>> [1] https://github.com/systemd/systemd/pull/24265
>
> Hello!
>
> In some cases "label" DT property can be used also as interface name.
> For example this property is already used by DSA kernel driver.
>
> I created very simple script which renames all interfaces in system to
> their "label" DT property (if there is any defined).
>
> #!/bin/sh
> for iface in `ls /sys/class/net/`; do
> for of_node in of_node device/of_node; do
> if test -e /sys/class/net/$iface/$of_node/; then
> label=`cat /sys/class/net/$iface/$of_node/label 2>/dev/null`
> if test -n "$label" && test "$label" != "$iface"; then
> echo "Renaming net interface $iface to $label..."
> up=$((`cat /sys/class/net/$iface/flags 2>/dev/null || echo 1` & 0x1))
> if test "$up" != "0"; then
> ip link set dev $iface down
> fi
> ip link set dev $iface name "$label" && iface=$label
> if test "$up" != "0"; then
> ip link set dev $iface up
> fi
> fi
> break
> fi
> done
> done
>
> Maybe it would be better first to use "label" and then use ethernet alias?
>
It looks like there is already precedent for using ID_NET_LABEL_ONBOARD for
this purpose (on SMBios boards). It should be a fairly simple extension to
add that as well. However, I didn't find any uses of this in Linux or U-Boot
(although I did find plenty of ethernet LEDs). Do you have an example you
could point me to?
--Sean
