[getdns-api] Upstream servers

[Robert Groenenberg]

Hi,

I am looking into using getdns for doing ENUM queries from an
application. Based on the examples I've build a small test application
which works Ok as a stub resolver doing a query to a configured upstream
server.

According to the API doc (http://getdnsapi.org/spec.html#8.7) a /list/
of upstream servers can be configured. I would expect that when the
first server does not respond, the next one is queried. However, I found
that whatever the number of upstream servers configured only the first
is ever used (verified with tcpdump/wireshark), no matter what the
response (or lack thereof) from that first server is.

This is the configuration of my context:
{
  "all_context":
  {
    "append_name": GETDNS_APPEND_NAME_ALWAYS,
    "dns_transport_list":
    [
      GETDNS_TRANSPORT_UDP,
      GETDNS_TRANSPORT_TCP
    ],
    "dnssec_allowed_skew": 0,
    "edns_do_bit": 0,
    "edns_extended_rcode": 0,
    "edns_version": 0,
    "follow_redirects": GETDNS_REDIRECTS_FOLLOW,
    "limit_outstanding_queries": 0,
    "namespaces":
    [
      GETDNS_NAMESPACE_LOCALNAMES,
      GETDNS_NAMESPACE_DNS
    ],
    "suffix": [],
    "timeout": 200,
    "tls_authentication": GETDNS_AUTHENTICATION_NONE,
    "upstream_recursive_servers":
    [
      {
        "address_data": <bindata for 192.168.99.120>,
        "address_type": <bindata of "IPv4">,
        "tls_port": 853
      },
      {
        "address_data": <bindata for 192.168.99.121>,
        "address_type": <bindata of "IPv4">,
        "tls_port": 853
      },
      {
        "address_data": <bindata for 8.8.8.8>,
        "address_type": <bindata of "IPv4">,
        "tls_port": 853
      }
    ]
  },
  "implementation_string": <bindata of "https://getdnsapi.net">,
  "resolution_type": GETDNS_RESOLUTION_STUB,
  "version_string": <bindata of "0.9.0">
}
Did I miss something here?

For the query itself I use getdns_general(), e.g.:
if ((r = getdns_general(context, "8.1.2.7.5.9.3.4.1.1.3.e164.test.net.",
                                 GETDNS_RRTYPE_NAPTR,
                                 extensions, userarg, &transaction_id,
callback)))
        fprintf(stderr, "Error scheduling request: %s (%d)\n",
                getdns_get_errorstr_by_id(r), r);


Is there some way to configure multiple servers where on a timeout the
next one is tried?

Cheers,
Robert


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