Maintained by: NLnet Labs

[Unbound-users] get ttl in libunbound?

David Hubbard
Sat Nov 14 00:18:01 CET 2009

Hi Ondrej,

On Fri, Nov 13, 2009 at 4:10 PM, Ondřej Surý <ondrej at> wrote:
> On Fri, Nov 13, 2009 at 23:55, David Hubbard <david.c.hubbard at> wrote:
>> Hi all,
>> I'd like to get the TTL value for a DNS request. I looked at what it
>> would take to add this to struct ub_result and it doesn't look too
>> difficult - patch attached.
> Please don't change the existing API. In this case it could be solved
> just by recompiling all dependant programs, but generally changing
> existing API causes a lot of troubles (beware not adding new functions
> and data types - but really changing existing functions).

I agree - this patch breaks the ABI. I don't think this is an urgent
matter, so would it be acceptable to put this in the queue for
whenever the next major API changes happen?

I do want to use the full validating resolver (especially dnssec). I
also find the libunbound interface simpler, so my code is easy to
read. I'm trying to replace code that used a different dns resolver
library that has gone dormant and doesn't have dnssec support.

One possibility is to place unsigned* ttl at the end of struct
ub_result - then existing applications would not break. I think it
"looks nicer" where it is. Either way, it doesn't really matter.

Thanks for your consideration,