Marc A. Lehmann


EV::ADNS - lightweight asynchronous dns queries using EV and libadns


 use EV;
 use EV::ADNS;

 EV::ADNS::submit "", EV::ADNS::r_addr, EV::ADNS::qf_cname_loose, sub {
    my ($status, $expires, @a) = @_;
    warn $a[0]; # "" etc.



This is a simple interface to libadns (asynchronous dns) that integrates well and automatically into the EV event loop. The documentation for libadns is vital to understand this module, see

You can use it only with EV (directly or indirectly, e.g. via Glib::EV). Apart from loading and using the submit function you need not do anything (except run an EV event loop).


All the constants/enums from adns.h are available in the EV::ADNS namespace, without the adns_ prefix, i.e. adns_r_a becomes EV::ADNS::r_a and so on.


$query = EV::ADNS::submit "domain", $rrtype, $flags, $cb

Submits a new request to be handled. See the adns_submit C function description for more details. The function optionally returns a query object which can be used to cancel an in-progress request. You do not need to store the query object, even if you ignore it, the query will proceed.

The callback will be invoked with a result status, the time the resource record validity expires and zero or more resource records, one scalar per result record. Example:

   sub adns_cb {
      my ($status, $expires, @rr) = @_;
      if ($status == EV::ADNS::s_ok) {
         use JSON::XS;
         warn encode_json \@rr;

The format of result records varies considerably, here is some cursory documentation of how each record will look like, depending on the query type:

EV::ADNS::r_a, EV::ADNS::r_addr

An IPv4 address in dotted quad (string) form.

EV::ADNS::r_ns_raw, EV::ADNS::r_cname, EV::ADNS::r_ptr, EV::ADNS::r_ptr_raw

The resource record as a simple string.


An arrayref of strings.


A "host address", a hostname with any number of addresses (hint records).

The record will be an arrayref with domainname, adns status and any number of associated addresses: ["domain", adns_status, addr...].


An arrayref consisting of the two strings.

EV::ADNS::r_rp, EV::ADNS::r_rp_raw

An arrayref with two strings.


An arrayref consisting of the priority and a "host address" (see EV::ADNS::r_ns). Example:

   [10, [["", 0, "", "2404:6800:4008:c07::1a"]]]

An arrayref consisting of the priority and the hostname, e.g. [10, ""].

EV::ADNS::r_soa, EV::ADNS::r_soa_raw

An arrayref consisting of the primary nameserver, admin name, serial, refresh, retry expire and minimum times, e.g.:

  ["", "", 2000001102, 86400, 21600, 2592000, 172800]

The "raw" form doesn't mangle the e-mail address.


An arrayref consisting of the priority, weight, port and hostname, e.g.:

   [10, 10, 5060, ""]

The same as EV::ADNS::r_srv_raw, but the hostname is replaced by a "host address" (see EV::ADNS::r_ns).


A single octet string with the raw contents.

anything else

Currently undef.


Cancels a request that is in progress.

EV::ADNS::reinit undef, $resolvdata_or_undef

Cancels all outstanding queries, frees all adns state and reinitialises it. It is highly recommended to only call this when there are no outstanding requests.

The first argument must currently be specified as undef.

The second argument can be missing or undef; in which case the normal initialisation is done (such as reading the resolv.conf), or it might be a stirng, in which case no config files or environment variables will be read and the given string will be interpreted as the resolv.conf contents.


EV, Net::ADNS another interface to adns, maybe better, but without real support to integrate it into other event loops.


 Marc Lehmann <>