[Dibbler] Dibbler and lifetimes under Linux

Tomasz Mrugalski thomson at klub.com.pl
Mon Mar 14 09:09:05 CET 2011

On 14.03.2011 01:02, Karl Auer wrote:
> When using Dibbler with Linux, the lifetimes shown for addresses
> obtained via DHCPv6 are always given as "forever" (for example when
> using ip or ifconfig). Of course Dibbler is managing those addresses,
> and they become deprecated/invalid at the correct times, but it would be
> nice if Linux could be "informed" somehow, so that ip, ifconfig and
> similar utilities gave the correct lifetime info.
That's a valid suggestion. Some time ago (ok, it was couple years) I got
good excuse to not implement this. It was not supported by Linux kernel.
I've checked semi-recent (2.6.32) kernel sources and it is indeed
supported now.

Latest SVN (r1394) contains necessary changes. Addresses are now added
as dynamic with proper preferred/valid lifetimes configured and updated
accordingly (after RENEW/REBIND). I've tested this on 2.6.35 kernel.
Looking at the sources, it should work with at least 2.6.32 (possibly
older, but I didn't check). Please check if it works for you.

ip shows those lifetimes properly, but ifconfig does not. Are you sure
that ifconfig is capable of displaying such info? I've checked out
source code for net-tools 1.60 (the one used in Debian) and there is no
mention of "lft", "lifetime" and any ocurrences of preferred apply to
preferred family. I think ifconfig is old and lacking.

I propose a bet. If my code works and you are happy with it, you owe me
a beer. If the code needs fixes and you report a problem, I owe you a
beer. Any outstanding debt will be settled, if and when we ever meet. Do
we have a deal? :)


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