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


as written in PM my submitted script was an very ancient version. Find
attached the current Version. What I did there is if netmask is /32 then
set a device-route for the gateway-ip.

Sorry for confusion.


On 05.06.2012 18:50, Michael Tokarev wrote:
> On 05.06.2012 20:41, Jens Ott - Profitbricks wrote:
>> Michael
> []
>>> 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 via dev dummy0
>>> ip: RTNETLINK answers: No such process
>> That can't work.
> Sure, because the "gateway" isn't reachable
> when the netmask is /32, this is exactly what I described
> (quoted below).
>>  That's why my script sets the routers-variable to $ip
>> when netmask is "".
> And this does not work to.  I think you had a typo there.
> See:
> [ "$subnet" = "" ] && routers=$ip
> case "$1" in
>         renew|bound)
>                 if [ -n "$router" ] ; then
>                         for i in $router ; do
>                                 echo "Adding router $i"
>                                 route add default gw $i dev $interface metric $((metric++))
>                         done
>                 fi
> ..
> Note you're setting "routeS" while use "routeR".
> This is why it should not work exactly the same way
> as current busybox's version!
>> Somewhere in ARP-RFC it is defined that a router shall respond to
>> WHO-HAS requests where requester and sender is the same address. So you
>> actually set default-route to the assigned IP on /32-Assignments.
> Well.  In this case, the DHCP server should just set router
> correctly, to be the same as client address, everything will
> Just Work (tm).
> This is a good piece of information, and why I asked for a
> reproducer -- it didn't occur to me to use the same IP for
> router and client's own ip address, even if I know it might
> work exactly the way you describe by sending an ARP for everyhing.
> The same can also be achieved by using not own's IP address
> but all zeros, like,
>  ip route add default via dev eth0
> and this is even more correct, I think, this is equivalent
> of not specifying "via" at all.  Again, this can be set in
> the DHCP server.
> I thought about a different case, when you actually specify
> some non-dummy gateway, it is not this case...
> So, I guess, nothing should be fixed on the busybox/debian
> side, do you not agree? :)
> Thank you!
> /mjt
>>> 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 dev dummy0
>>> and second is the actual default (or whatever) route going
>>> via that gateway, the regular way:
>>>  # busybox ip r add via
>>> ("dev" is optional here, just like for the regular case).
>>> Alternative is to use the keyword "onlink":
>>>  # ip r add via dev dummy0 onlink
>>> but this does not work with busybox (yet).

Attachment: udhcp-script.tpl
Description: application/vnd.groove-tool-template

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