NAME

POE::Component::DHCP::Monitor - A simple POE Component for monitoring DHCP traffic.

VERSION

version 1.04

SYNOPSIS

  use strict;
  use POE;
  use POE::Component::DHCP::Monitor;
  use Net::DHCP::Packet;

  $|=1;

  POE::Session->create(
        inline_states => {
                                _start              => \&_start,
        _default      => \&_default,
                                dhcp_monitor_packet => \&dhcp_monitor_packet,
        },
  );

  $poe_kernel->run();
  exit 0;

  sub _start {
    my ($kernel,$heap) = @_[KERNEL,HEAP];
    $heap->{monitor} =
        POE::Component::DHCP::Monitor->spawn(
                alias => 'monitor',       # optional
                port1  => 67,             # default shown
                port2  => 68,             # default shown
                address => '192.168.1.1', # default is INADDR_ANY
        );
    return;
  }

  sub dhcp_monitor_packet {
    my ($kernel,$heap,$packet) = @_[KERNEL,HEAP,ARG0];
    print STDOUT $packet->toString();
    print STDOUT "=============================================================================\n";
    return;
  }

  # This should show any unhandled events
  sub _default {
    my ($event, $args) = @_[ARG0 .. $#_];
    my @output = ( "$event: " );

    for my $arg (@$args) {
        if ( ref $arg eq 'ARRAY' ) {
            push( @output, '[' . join(', ', @$arg ) . ']' );
        }
        else {
            push ( @output, "'$arg'" );
        }
    }
    print join ' ', @output, "\n";
    return;
  }

DESCRIPTION

POE::Component::DHCP::Monitor is a simple POE Component for monitoring DHCP traffic. It listens on a specified port ( defaults to 67, which usually requires administrative privilege ). Any DHCP broadcast traffic received will generate an event with a Net::DHCP::Packet object as the first argument. You may then query the objects methods to obtain salient information.

CONSTRUCTOR

spawn

Starts a new POE::Component::DHCP::Monitor session. If this is called from within another POE session then that session is automagically registered to receive events from the component. Other sessions will have to use the 'register' event listed below.

Takes a number of arguments:

  'alias', an optional kernel alias to address the poco by;
  'address', set a particular IP address on a multi-homed box to bind to;
  'port', set a particular UDP port to listen on, default is 67;
  'port2', set a particular UDP port to listen on, default is 67;
  'options', pass a hashref of POE session options;
  'prefix', optional set the output event prefix, default is 'dhcp_monitor_';

METHODS

These methods are available on the POE::Component::DHCP::Monitor object:

session_id

Returns the POE session ID of the poco's session.

shutdown

Terminates the poco, unregistering all registered sessions and closes the listening socket.

getsockname

Returns the packed sockaddr address of this end of the first socket connection.

getsockname2

Returns the packed sockaddr address of this end of the second socket connection.

INPUT EVENTS

The component accepts the following events:

register

Takes no arguments. This registers your session with the component. The component will then send the registering session a 'registered' event. The session will forthwith receive applicable events from the component, until either the component is shutdown or the session unregisters.

unregister

Takes no arguments. This unregisters your session with the component. The unregistering session will receive an 'unregistered' event.

shutdown

Terminates the poco, unregistering all registered sessions and closes the listening socket.

OUTPUT EVENTS

The component will send the following events:

dhcp_monitor_socket

Sent by the component to 'registered' sessions when the socket is successfully started. ARG0 will be the packed sockaddr address of the socket.

dhcp_monitor_packet

Sent by the component to 'registered' sessions when a DHCP packet is received and successfully parsed. ARG0 will be a Net::DHCP::Packet. ARG1 will be the port number this packet was received on.

dhcp_monitor_registered

Sent by the component to a registering session only on successful registration. ARG0 is the components object.

dhcp_monitor_unregistered

Sent by the component to an unregistering session only on successful unregistration.

dhcp_monitor_sockbinderr

Sent by the component to 'registered' sessions when an error occurs in setting up the listening socket. ARG0 is the error string. The component will shutdown automatically after such an error.

dhcp_monitor_sockopterr

Sent by the component to 'registered' sessions when an error occurs in setting the SOL_SOCKET and SO_BROADCAST options on the socket. ARG0 is the error string. The component will shutdown automatically after such an error.

dhcp_monitor_sockrecverr

Sent by the component to 'registered' sessions when an error occurs in reading a packet from the socket.

dhcp_monitor_sockpackerr

Sent by the component to 'registered' sessions when an error occurs in parsing a received packet using Net::DHCP::Packet.

SEE ALSO

Net::DHCP::Packet

AUTHOR

Chris Williams <chris@bingosnet.co.uk>

COPYRIGHT AND LICENSE

This software is copyright (c) 2012 by Chris Williams.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.