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NAME
Net::DNS::Resolver::Programmable - programmable DNS resolver class for
offline emulation of DNS
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, $aa, @rrs);
}
);
DESCRIPTION
Net::DNS::Resolver::Programmable is a Net::DNS::Resolver descendant
class that allows a virtual DNS to be emulated instead of querying the
real DNS. A set of static DNS records may be supplied, or arbitrary
code may be specified as a means for retrieving DNS records, or even
generating them on the fly.
Constructor
The following constructor is provided:
new(%options): returns Net::DNS::Resolver::Programmable
Creates a new programmed DNS resolver object.
%options is a list of key/value pairs representing any of the
following options:
records
A reference to a hash of arrays containing a static set of
Net::DNS::RR objects. The hash entries must be indexed by fully
qualified domain names (lower-case, without any trailing dots), and
the entries themselves must be arrays of the RR objects pertaining
to these domain names. For example:
records => {
'example.com' => [
Net::DNS::RR->new('example.com. NS ns.example.org.'),
Net::DNS::RR->new('example.com. A 192.168.0.1')
],
'www.example.com' => [
Net::DNS::RR->new('www.example.com. A 192.168.0.2')
],
'ns.example.org' => [
Net::DNS::RR->new('ns.example.org. A 192.168.1.1')
]
}
If this option is specified, the resolver retrieves requested RRs
from this data structure.
resolver_code
A code reference used as a call-back for dynamically retrieving
requested RRs.
The code must take the following query parameters as arguments: the
domain, RR type, and class.
It must return a list composed of: the response's RCODE (by name,
as returned by Net::DNS::Header->rcode), the aa (authoritative
answer) flag (boolean, use undef if you don't care), and the
Net::DNS::RR answer objects. If an error string is returned instead
of a valid RCODE, a Net::DNS::Packet object is not constructed but
an error condition for the resolver is signaled instead.
For example:
resolver_code => sub {
my ($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
David Precious (BIGPRESH) <davidp@preshweb.co.uk> took on
maintainership in July 2017
Original author Julian Mehnle <julian@mehnle.net>
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