Bug#652573: busybox-udeb: debian stable busybox udhcp client does not support /32 netmasks

[Michael Tokarev <mjt@tls.msk.ru>]

On 05.06.2012 20:10, Michael Tokarev wrote:
[]
> It is not udhcpc, and not the udhcpc script either.  It is busybox's
> `ip' utility.
> 
> # busybox ip -4 add 192.168.77.10/32 dev dummy0
> ip: invalid argument '192.168.77.10/32' to 'ip'

And this is, ofcourse, a typo...  I forgot to use `addr'.

> # busybox ip -4 add 192.168.77.10/31 dev dummy0

And this one I actually didn't run at all, hitting CtrlC
instead of Enter!

That's what happens when you do things when you're too
tired... :(  Please excuse me for the noize.  Digging
further, and I'll update the bugreports accordingly
(will restore it all back if I wont be able to find
the issue).

For now I see another _possible_ issue, which needs
to be verified in d-i: this is the place which adds
routes.  Neither debian default.script nor your script
is able to add routes:

# busybox ip r add 10.255.0.0/28 via 192.168.77.11 dev dummy0
ip: RTNETLINK answers: No such process

The same happens when using route(8) utility.  For this
to work, two routes should be added: first to the gateway
host, without the "via" part:

 # busybox ip r add 192.168.77.11 dev dummy0

and second is the actual default (or whatever) route going
via that gateway, the regular way:

 # busybox ip r add 10.255.0.0/28 via 192.168.77.11

("dev" is optional here, just like for the regular case).

Alternative is to use the keyword "onlink":

 # ip r add 10.255.0.0/28 via 192.168.77.11 dev dummy0 onlink

but this does not work with busybox (yet).

I think this /32 case is worth to handle specially, using the
onlink or two route entries.

But I'm not sure this is the actual case the regular bug is
about: for the route to work with netmask != /32, the gateway
must be within the netmask, so if you specify, eg, 1.1.1.1/31
for the client, the router must be 1.1.1.0.

Does it look real?

But again, please note that the script provided by Jens should
fail exactly the same way!  So... I guess it is not the issue... :(

Thank you for patience!

/mjt