NetPacket::ARP - Assemble and disassemble ARP (Address Resolution Protocol) packets.

       Tim Potter <tpot@samba.org>

perl v5.36.0                                       2022-11-19                                NetPacket::ARP(3pm)

       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.

       "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.

   Instancedata
       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.

       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);

       NetPacket::ARP - Assemble and disassemble ARP (Address Resolution Protocol) packets.

         use NetPacket::ARP;

         $tcp_obj = NetPacket::ARP->decode($raw_pkt);
         $tcp_pkt = NetPacket::ARP->encode(params...);   # Not implemented

       Implement encode() function
       Does this work for protocols other than IP?  Need to read RFC.
       Example is a bit silly

       version 1.7.2