dhcpcd: raw-ip support

Yegor Yefremov yegorslists at googlemail.com
Mon Aug 19 12:25:43 UTC 2019

On Mon, Aug 19, 2019 at 10:49 AM Bjørn Mork <bjorn at mork.no> wrote:
> Yegor Yefremov <yegorslists at googlemail.com> writes:
> > I have a project where I'm using dhcpcd client. It is working without
> > any problems with older modems like Quectel UC20 etc. But now we want
> > to switch to SIM7600G-H and it is working in raw-ip mode. So far only
> > udhcpc can handle such MAC address-less interfaces.
> >
> > Do you know what is so special about udhcpc compared to other DHCP
> > clients?
> It's mostly L2 agnostic, meaning that it will work on non-ethernet
> interfaces.
> "Fixing" this for other clients isn't really that hard, if required. I
> did this proof-of-concept for ISC dhclient for example:
>  https://mail.gnome.org/archives/networkmanager-list/2015-December/msg00044.html

Thanks for the patch. But looks like it hasn't been upstreamed yet :-(

Will dig further.


> > Is there any raw-ip related documentation?
> Not really. Just delete "ethernet" from other documentation :-)
> The only difference is that the ethernet header is removed from the
> packets between host and modem.  It is not replaced by anything.
> We could have made up a new "ARP hardware type" for this, but I didn't
> see much point.  The "hardware type" is simply no header and no
> address. So I went with the example from the tuntap driver, using
> Bjørn

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