NAME¶
NetPacket::ARP - Assemble and disassemble ARP (Address Resolution Protocol)
packets.
VERSION¶
version 1.3.0
SYNOPSIS¶
use NetPacket::ARP;
$tcp_obj = NetPacket::ARP->decode($raw_pkt);
$tcp_pkt = NetPacket::ARP->encode(params...); # Not implemented
DESCRIPTION¶
"NetPacket::ARP" provides a set of routines for assembling and
disassembling packets using ARP (Address Resolution Protocol).
Methods¶
- "NetPacket::ARP->decode([RAW PACKET])"
- Decode the raw packet data given and return an object
containing instance data. This method will quite happily decode garbage
input. It is the responsibility of the programmer to ensure valid packet
data is passed to this method.
- "NetPacket::ARP->encode(param =>
value)"
- Return a ARP packet encoded with the instance data
specified. Not implemented.
Functions¶
- "NetPacket::ARP::strip([RAW PACKET])"
- Return the encapsulated data (or payload) contained in the
TCP packet. Since no payload data is encapulated in an ARP packet (only
instance data), this function returns undef.
Instance data¶
The instance data for the "NetPacket::ARP" object consists of the
following fields.
- htype
- Hardware type.
- proto
- Protocol type.
- hlen
- Header length.
- plen
- Protocol length.
- opcode
- One of the following constants:
- •
- ARP_OPCODE_REQUEST
- •
- ARP_OPCODE_REPLY
- •
- RARP_OPCODE_REQUEST
- •
- RARP_OPCODE_REPLY
- sha
- Source hardware address.
- spa
- Source protocol address.
- tha
- Target hardware address.
- tpa
- Target protocol address.
Exports¶
- default
- none
- exportable
- none
- tags
- The following tags group together related exportable
items.
- ":ALL"
- All the above exportable items.
EXAMPLE¶
Print out arp requests on the local network.
#!/usr/bin/perl -w
use Net::PcapUtils;
use NetPacket::Ethernet qw(:types);
use NetPacket::ARP;
sub process_pkt {
my ($arg, $hdr, $pkt) = @_;
my $eth_obj = NetPacket::Ethernet->decode($pkt);
if ($eth_obj->{type} == ETH_TYPE_ARP) {
my $arp_obj = NetPacket::ARP->decode($eth_obj->{data}, $eth_obj);
print("source hw addr=$arp_obj->{sha}, " .
"dest hw addr=$arp_obj->{tha}\n");
}
}
Net::PcapUtils::loop(\&process_pkt);
TODO¶
- Implement encode() function
- Does this work for protocols other than IP? Need to read
RFC.
- Example is a bit silly
COPYRIGHT¶
Copyright (c) 2001 Tim Potter.
Copyright (c) 1995,1996,1997,1998,1999 ANU and CSIRO on behalf of the
participants in the CRC for Advanced Computational Systems ('ACSys').
This module is free software. You can redistribute it and/or modify it under the
terms of the Artistic License 2.0.
This program is distributed in the hope that it will be useful, but without any
warranty; without even the implied warranty of merchantability or fitness for
a particular purpose.
AUTHOR¶
Tim Potter <tpot@samba.org>