NAME
POE::Component::Server::DNS - A non-blocking, concurrent DNS server POE
component
VERSION
version 0.32
SYNOPSIS
use strict;
use Net::DNS::RR;
use POE qw(Component::Server::DNS);
my $dns_server = POE::Component::Server::DNS->spawn( alias => 'dns_server' );
POE::Session->create(
package_states => [ 'main' => [ qw(_start handler log) ], ],
);
$poe_kernel->run();
exit 0;
sub _start {
my ($kernel,$heap) = @_[KERNEL,HEAP];
# Tell the component that we want log events to go to 'log'
$kernel->post( 'dns_server', 'log_event', 'log' );
# register a handler for any foobar.com suffixed domains
$kernel->post( 'dns_server', 'add_handler',
{
event => 'handler',
label => 'foobar',
match => 'foobar\.com$',
}
);
undef;
}
sub handler {
my ($qname,$qclass,$qtype,$callback) = @_[ARG0..ARG3];
my ($rcode, @ans, @auth, @add);
if ($qtype eq "A") {
my ($ttl, $rdata) = (3600, "10.1.2.3");
push @ans, Net::DNS::RR->new("$qname $ttl $qclass $qtype $rdata");
$rcode = "NOERROR";
} else {
$rcode = "NXDOMAIN";
}
$callback->($rcode, \@ans, \@auth, \@add, { aa => 1 });
undef;
}
sub log {
my ($ip_port,$net_dns_packet) = @_[ARG0..ARG1];
$net_dns_packet->print();
undef;
}
DESCRIPTION
POE::Component::Server::DNS is a POE component that implements a DNS
server.
It uses POE::Component::Client::DNS to handle resolving when configured
as 'forward_only' and Net::DNS::Resolver::Recurse wrapped by
POE::Component::Generic to perform recursion.
One may add handlers to massage and manipulate responses to particular
queries which is vaguely modelled after Net::DNS::Nameserver.
CONSTRUCTOR
spawn
Starts a POE::Component::Server::DNS component session and returns an
object. Takes a number of optional arguments:
"alias", an alias to address the component by;
"port", which udp port to listen on. Default is 53, which requires 'root' privilege on UN*X type systems;
"address", which local IP address to listen on. Default is INADDR_ANY;
"resolver_opts", a set of options to pass to the POE::Component::Client::DNS constructor;
"forward_only", be a forwarding only DNS server. Default is 0, be recursive.
"no_clients", do not spawn client code (See following notes);
"no_clients" disables the spawning of client code (PoCo::Client::DNS,
Net::DNS::Resolver::Recursive), and doesn't attempt to forward or
recurse inbound requests. Any request not handled by one of your
handlers will be REFUSED. Saves some resources when you intend your
server to be authoritative only (as opposed to a general resolver for
DNS client software to point at directly). Additionally, this
argument changes the default "Recursion Available" flag in responses
to off instead of on.
METHODS
These are methods that may be used with the object returned by spawn().
session_id
Returns the POE::Session ID of the component's session.
resolver
Returns a reference to the POE::Component::Client::DNS object.
shutdown
Terminates the component and associated resolver.
sockport
Returns the port of the socket that the component is listening on.
INPUT EVENTS
These are states that the component will accept:
add_handler
Accepts a hashref as an argument with the following keys:
"event", the event the component will post to, mandatory;
"label", a unique name for this handler, mandatory;
"match", a regex expression ( without // ) to match against the host part of queries, mandatory;
"session", the session where this handler event should be sent to, defaults to SENDER;
See OUTPUT EVENTS for details of what happens when a handler is
triggered.
del_handler
Accepts a handler label to remove.
log_event
Tells the component that a session wishes to receive or stop
receiving DNS log events. Specify the event you wish to receive log
events as the first argument. If no event is specified you stop
receiving log events.
shutdown
Terminates the component and associated resolver.
HANDLER EVENTS
These events are triggered by a DNS query matching a handler. The
applicable event is fired in the requested session with the following
paramters:
ARG0, query name
ARG1, query class
ARG2, query type
ARG3, a callback coderef
ARG4, the IP address and port of the requestor, 'IPaddr:port'
Do your manipulating then use the callback to fire the response back to
the component, returning a response code and references to the answer,
authority, and additional sections of the response. For advanced usage
there is an optional argument containing an hashref with the settings
for the aa, ra, and ad header bits. The argument is of the form { ad =>
1, aa => 0, ra => 1 }.
$callback->( $rcode, \@ans, \@auth, \@add, { aa => 1 } );
LOG EVENTS
These events are triggered whenever a DNS response is sent to a client.
ARG0, the IP address and port of the requestor, 'IPaddr:port';
ARG1, the Net::DNS::Packet object;
See Net::DNS::Packet for details.
HISTORY
The component's genesis was inspired by Jan-Pieter's 'Fun with POE'
talk at YAPC::EU 2006, which lay much of the ground-work code such as
the POE::Driver and POE::Filter used internally. BinGOs wrapped it all
up in a component, added the tests ( borrowed shamelessly from
POE::Component::Client::DNS's testsuite ) and documentation.
Other suggestions as to the API were provided by Ben 'integral' Smith.
Rocco Caputo brought POE::Component::Client::DNS to the party.
SEE ALSO
POE::Component::Client::DNS
POE::Component::Generic
Net::DNS
Net::DNS::Packet
AUTHORS
* Chris Williams <chris@bingosnet.co.uk>
* Jan-Pieter Cornet <johnpc@xs4all.nl>
* Brandon Black <blblack@gmail.com>
* Richard Harman <richard@richardharman.com>
* Stephan Jauernick <stephan@stejau.de>
COPYRIGHT AND LICENSE
This software is copyright (c) 2015 by Chris Williams, Jan-Pieter
Cornet, Brandon Black, Richard Harman and Stephan Jauernick.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.