Net::DNS::Resolver::PrUsermContributed PerlNet::DNS::Resolver::Programmable(3)NAMENet::DNS::Resolver::Programmable - programmable DNS resolver class for
offline emulation of DNS
VERSION
0.003
SYNOPSIS
use Net::DNS::Resolver::Programmable;
use Net::DNS::RR;
my $resolver = Net::DNS::Resolver::Programmable->new(
records => {
'example.com' => [
Net::DNS::RR->new('example.com. NS ns.example.org.'),
Net::DNS::RR->new('example.com. A 192.168.0.1')
],
'ns.example.org' => [
Net::DNS::RR->new('ns.example.org. A 192.168.1.1')
]
},
resolver_code => sub {
my ($domain, $rr_type, $class) = @_;
...
return ($result, $aa, @rrs);
}
);
DESCRIPTIONNet::DNS::Resolver::Programmable is a Net::DNS::Resolver descendant
class that allows a virtual DNS to be emulated instead of querying the
real DNS. A set of static DNS records may be supplied, or arbitrary
code may be specified as a means for retrieving DNS records, or even
generating them on the fly.
Constructor
The following constructor is provided:
new(%options): returns Net::DNS::Resolver::Programmable
Creates a new programmed DNS resolver object.
%options is a list of key/value pairs representing any of the
following options:
records
A reference to a hash of arrays containing a static set of
Net::DNS::RR objects. The hash entries must be indexed by
fully qualified domain names (lower-case, without any trailing
dots), and the entries themselves must be arrays of the RR
objects pertaining to these domain names. For example:
records => {
'example.com' => [
Net::DNS::RR->new('example.com. NS ns.example.org.'),
Net::DNS::RR->new('example.com. A 192.168.0.1')
],
'www.example.com' => [
Net::DNS::RR->new('www.example.com. A 192.168.0.2')
],
'ns.example.org' => [
Net::DNS::RR->new('ns.example.org. A 192.168.1.1')
]
}
If this option is specified, the resolver retrieves requested
RRs from this data structure.
resolver_code
A code reference used as a call-back for dynamically retrieving
requested RRs.
The code must take the following query parameters as arguments:
the domain, RR type, and class.
It must return a list composed of: the response's RCODE (by
name, as returned by Net::DNS::Header->rcode), the "aa"
(authoritative answer) flag (boolean, use undef if you don't
care), and the Net::DNS::RR answer objects. If an error string
is returned instead of a valid RCODE, a Net::DNS::Packet object
is not constructed but an error condition for the resolver is
signaled instead.
For example:
resolver_code => sub {
my ($domain, $rr_type, $class) = @_;
...
return ($result, $aa, @rrs);
}
If both this and the "records" option are specified, then
statically programmed records are used in addition to any that
are returned by the configured resolver code.
defnames
dnsrch
domain
searchlist
debug
These Net::DNS::Resolver options are also meaningful with
Net::DNS::Resolver::Programmable. See Net::DNS::Resolver for
their descriptions.
Instance methods
The following instance methods of Net::DNS::Resolver are also supported
by Net::DNS::Resolver::Programmable:
search: returns Net::DNS::Packet
query: returns Net::DNS::Packet
send: returns Net::DNS::Packet
Performs an offline DNS query, using the statically programmed DNS
RRs and/or the configured dynamic resolver code. See the "new"
constructor's "records" and "resolver_code" options. See the
descriptions of search, query, and send for details about the
calling syntax of these methods.
print
string: returns string
searchlist: returns list of string
defnames: returns boolean
dnsrch: returns boolean
debug: returns boolean
errorstring: returns string
answerfrom: returns string
answersize: returns integer
See "METHODS" in Net::DNS::Resolver.
Currently the following methods of Net::DNS::Resolver are not
supported: axfr, axfr_start, axfr_next, nameservers, port, srcport,
srcaddr, bgsend, bgread, bgisready, tsig, retrans, retry, recurse,
usevc, tcp_timeout, udp_timeout, persistent_tcp, persistent_udp, igntc,
dnssec, cdflag, udppacketsize. The effects of using these on
Net::DNS::Resolver::Programmable objects are undefined.
SEE ALSO
Net::DNS::Resolver
For availability, support, and license information, see the README file
included with Net::DNS::Resolver::Programmable.
AUTHORS
Julian Mehnle <julian@mehnle.net>
perl v5.16.22013-08-2Net::DNS::Resolver::Programmable(3)
