docs: add deprecation note for dns function

[createyourpersonalaccount]

No description provided.

[createyourpersonalaccount]

Hm, I've noticed that I get an ARES_EBADRESP even though I haven't configured a DNS server for the channel nor a query for the record. Is this a bug? The situation is:

ares_init_options(&channel, &options, ARES_OPT_EVENT_THREAD);
ares_dns_record_create(&dnsrec, 0, 0, ARES_OPCODE_QUERY, 0);
ares_send_dnsrec(channel, dnsrec, callback, NULL, &query_id);
ares_dns_record_destroy(dnsrec);
ares_destroy(channel);
ares_library_cleanup();
exit(0);

I know that I'm supposed to wait for the query, I'm just wondering if ARES_EBADRESP is an appropriate status in this situation for the callback.

[bradh352]

Its possible that this is a bad error code, it maybe should be ARES_EBADQUERY since your query isn't properly formed, you're missing the actual question, use ares_dns_record_query_add(). My guess is its this line that's generating that error code:

c-ares/src/lib/ares_send.c

Line 154 in a70637c

status = ares_dns_record_duplicate_ex(&query->query, dnsrec);

The duplicate query writes out the query as binary, then parses it into a new data structure. The parse likely failed due to missing the question hence ARES_EBADRESP since a parser is typically used on responses. I probably need to look at the duplicate function and catch this to rewrite the error code.

[bradh352]

the status code should be better reflected in 91519e7 if I'm correct

[createyourpersonalaccount]

@bradh352 does this look okay?

[bradh352]

ARES_ENOSERVER is definitely a valid return code to ares_send() and friends, why did it get removed?

[createyourpersonalaccount]

ARES_ENOSERVER is definitely a valid return code to ares_send() and friends, why did it get removed?

Oops! I meant to change the status I introduced, ARES_EBADRESP, not ARES_ENOSERVER.