Hi,
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.
BR
Jens
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 10.255.0.0/28 via 192.168.77.11 dev dummy0
>>> ip: RTNETLINK answers: No such process
>>
>> That can't work.
>
> Sure, because the "gateway" 192.168.77.11 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 $ip
>> when netmask is "255.255.255.255".
>
> And this does not work to. I think you had a typo there.
> See:
>
> [ "$subnet" = "255.255.255.255" ] && 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 0.0.0.0 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 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).
Attachment:
udhcp-script.tpl
Description: application/vnd.groove-tool-template