02-08-2012
Either way is fine. Backticks are used in post #2.. $() will work equally well.
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LEARN ABOUT DEBIAN
poe::component::pcap
Pcap(3pm) User Contributed Perl Documentation Pcap(3pm)
## Need an IO::Handle to $kernel->select_read() upon
$heap->{fdh} = IO::Handle->new_from_fd( $heap->{fd}, "r" )
or die "Can't create IO::Handle from pcap fd: $!
";
NAME
POE::Component::Pcap - POE Interface to Net::Pcap
SYNOPSIS
use POE::Component::Pcap;
POE::Component::Pcap->spawn(
Alias => 'pcap',
Device => 'eth0',
Filter => 'host fooble or host blort',
Dispatch => 'got_packet',
Session => $my_session_id,
);
$poe_kernel->post( pcap => open_live =>
'eth0', 80, 1, 100 );
$poe_kernel->post( pcap => set_filter => 'arp or host zooble' );
$poe_kernel->post( pcap => set_dispatch => 'target_state' );
$poe_kernel->post( pcap => 'run' );
$poe_kernel->post( pcap => 'shutdown' );
DESCRIPTION
POE::Component::Pcap provides a wrapper for using the Net::Pcap module from POE programs. The component creates a separate session which
posts events to a specified session and state when packets are available.
ARGUMENTS
Alias
The alias for the Pcap session. Used to post events such as "run" and "shutdown" to control the component. Defaults to "pcap" if not
specified.
Device
As a shortcut, the device for Net::Pcap to watch may be specified when creating the component. If this argument is used,
Net::Pcap::open_live will be called with a snaplen of 80 octets, a timeout of 100ms, and the interface will be put in promiscuous mode.
If these values are not suitable, post an "open_live" event instead.
Filter
Another shortcut, calls Net::Pcap::compile and Net::Pcap::setfilter to set a packet filter. This can only be used if the Device
argument is also given; otherwise a "set_filter" event should be posted after an "open_live" event (since Net::Pcap must have a
"pcap_t" descriptor to work with).
Dispatch
Session
These specify the session and state to which events should be posted when packets are received.
EVENTS
The following examples assume that the component's alias has been set to the default value of pcap.
open_live
$_[KERNEL]->post( pcap => open_live
=> 'device', [snaplen], [promsic?], [timeout] );
Calls Net::Pcap::open_live. The device name must be specified. The snaplen, promiscuous, and timeout parameters default to 80, 1, and
100 respectively. This event must be posted (or the Device argument must have been passed to spawn()) before anything else can be done
with the component.
set_filter
$_[KERNEL]->post( pcap => set_filter
=> 'host fooble or host blort' )
Sets the Net::Pcap capture filter. See tcpdump(8) for details on the filter language used by pcap(3).
set_dispatch
$_[KERNEL]->post( pcap => set_dispatch
=> 'target_state', 'target_session' );
Sets the state and session to which events are sent when packets are recevied. The target session will default to the sender of the
event if not specified.
The event posted will have a single argument (available as ARG0) which will be an array reference containing the $hdr and $pkt
parameters from Net::Pcap. See the Net::Pcap(3) documentation for more details.
run
$_[KERNEL]->post( pcap => 'run' );
Causes the component to register a select_read and start watching for packets.
shutdown
$_[KERNEL]->post( pcap => 'shutdown' );
Shuts the component down. Causes Net::Pcap::close to be called.
SEE ALSO
Net::Pcap(3), pcap(3), tcpdump(8), POE(3), POE::Component(3)
AUTHOR
Mike Fletcher, <fletch@phydeaux.org>
COPYRIGHT
Copyright 2000-2001, Mike Fletcher. All Rights Reserved. This is free software; you may redistribute it and/or modify it under the same
terms as Perl itself.
perl v5.10.1 2008-01-28 Pcap(3pm)