[ldns-users] simple use case - change domain in query

[Michael Ellery]

Matthijs,

Thanks for your reply. It looks like switching to ldns_str2rdf_dname() has fixed my problem, at least in preliminary testing.

Best,
Mike


On Nov 30, 2012, at 1:15 AM, Matthijs Mekking wrote:

> Hi Mike,
> 
> It is hard to tell, the code example is obviously not complete. What error is ldns_wire2pkt giving you? Perhaps you can use ldns_pkt_print() to see how the new packet looks like.
> 
> Also, I guess you want to use ldns_str2rdf_dname() instead of ldns_str2rdf_str() .
> 
> Best regards,
>  Matthijs
> 
> 
> On 11/29/2012 10:41 PM, Michael Ellery wrote:
>> Hello LDNS users,
>> 
>> I'm trying to use LDNS to tweak an existing DNS request. In this case, I
>> want to modify the domain in the query. Here is the code I've tried so
>> far (minus error checking):
>> 
>> /* dns_data, dns_data_len, and new_domain are inputs */
>> 
>>     ldns_pkt    *query     = NULL;
>>     ldns_rr     *question  = NULL;
>>     ldns_rdf    *new_name  = NULL;
>>     uint8_t     *new_dns_data = NULL
>>     size_t       new_dns_data_len = 0U;
>> 
>>     ldns_wire2pkt(&query, dns_data, dns_data_len);
>>     ldns_str2rdf_str(&new_name, new_domain);
>>     question = ldns_rr_list_rr(ldns_pkt_question(query), 0U);
>>     ldns_rr_set_owner(question, new_name);
>>     ldns_pkt2wire(&new_dns_data, query, &new_dns_data_len);
>>     ldns_pkt_free(query);
>> 
>> 
>> The code runs and doesn't produce any errors (I'm checking return
>> codes), but the resulting buffer in new_dns_data subsequently fails in a
>> call to ldns_wire2pkt, so I assume that means it's invalid or corrupt.
>> 
>> Any thoughts about what I'm doing wrong or another way to accomplish
>> what I'd like to do (change the FQDN in the query..).
>> 
>> Thanks,
>> Mike Ellery
>> 
>> 
>> 
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>