[ldns-users] How to use _searchlist provided by ldns_struct_resolver?

Zbynek Michl zbynek.michl at nic.cz
Tue Sep 14 16:46:56 UTC 2010

Hi Matthijs,

I have tried to make a dname like this:

domain = ldns_dname_new_frm_str("myhostname");
new_domain = ldns_dname_new_frm_data(ldns_rdf_size(domain) - 1,
printf("domain: %s\n", ldns_rdf2str(domain));
printf("new_domain: %s\n", ldns_rdf2str(new_domain));

It is strange for me that both printf()s print the same result (with dot at the 
end). And then when I use:

p = ldns_resolver_search(res, new_domain, LDNS_RR_TYPE_A,
                          LDNS_RR_CLASS_IN, LDNS_RD);

resolver returns FORMERR, because ldns_resolver_search() uses ldns_rdf2str() 
which causes to call ldns_resolver_query() with incorrect domain name.

Another error of ldns_resolver_search() is that it does not check RCODE.
In case of this resolv.conf:

search mydomain.com
search mydomain.cz

and query for "myhostname" will try just first search value even if NXDOMAIN is 

Last error that I have observed is that ldns_resolver_new_frm_file() reads just 
first domain name on line, so this searchlist definition is not read completely:

search mydomain.com mydomain.cz


On 12.5.2010 09:04, Matthijs Mekking wrote:
> Hash: SHA1
> Hi Zbynek,
> Sorry for the late follow-up. You are right that making a dname from
> string always returns an absolute dname. You can try making a dname with
> ldns_dname_new_frm_data().
> Best regards,
> Matthijs
> Zbynek Michl wrote:
>> Hello,
>> I am trying to use search list, but unsuccessfully. Here is an sample:
>> --- CODE ---
>> ldns_rdf *domain = ldns_dname_new_frm_str("myhostname");
>> ldns_rdf *search = ldns_dname_new_frm_str("mydomain.cz");
>> ldns_resolver_push_searchlist(res, search);
>> p = ldns_resolver_search(res, domain, LDNS_RR_TYPE_A,
>>               LDNS_RR_CLASS_IN, LDNS_RD);
>> --- /CODE ---
>> The problem is that "myhostname.mydomain.cz" will never be tried,
>> because of ldns_dname_new_frm_str() adds "." to the end of "myhostname"
>> and therefore ldns_resolver_search() will not concatenate "mydomain.cz".
>> So how can I create "myhostname" RDF without trailing "."? Or any other
>> suggestion?
>> Cheers,
>> Zbynek
>> _______________________________________________
>> ldns-users mailing list
>> ldns-users at open.nlnetlabs.nl
>> http://open.nlnetlabs.nl/mailman/listinfo/ldns-users
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