#!/usr/bin/perl

# This program will send either a UDP or TCP packet with a faked
# source address to a destination address for IPv4 or IPv6
use strict;
use warnings;

use Switch;
use Net::Packet::Env qw($Env);
use Net::Packet::Consts qw(:ipv6 :eth);
require Net::Packet::Frame;
require Net::Packet::DescL3;
require Net::Packet::Dump;
require Net::Packet::IPv4;
require Net::Packet::IPv6;
require Net::Packet::UDP;
require Net::Packet::TCP;
require Net::Packet::ETH;

my $transport;
my $port;
my $version;
my $eth;
my $ip;
my $l4;
my $frame;
my $srcAddr;
my $dstAddr;
my $if;

handleArgs(@ARGV);

printEnv();

my $env = Net::Packet::Env->new(dev => $if);

my $dump = Net::Packet::Dump->new(
	keepTimestamp => 1,
	env => $env,
);

$dump->start;

# Build network layer header (ip4 or ip6)
# defualts to ip4
if($version eq '6')
{	
	$eth = Net::Packet::ETH->new(
		type => NP_ETH_TYPE_IPv6,
		dst => '00:B0:D0:7B:BC:AE',
	);
	$ip = Net::Packet::IPv6->new(
		src => $srcAddr,
		dst => $dstAddr,
	);
}
else
{
	$ip = Net::Packet::IPv4->new(
		src => $srcAddr,
		dst => $dstAddr,
	);
}

# Build a transport layer header
# defaults to tcp
if($transport eq 'udp')
{
	$l4 = Net::Packet::UDP->new(
		dst => $port,
	);
}
else
{
	$l4 = Net::Packet::TCP->new(
		dst => $port,
	);
}

# Assemble a frame
if($version eq '6')
{
	$frame = Net::Packet::Frame->new(
		l2 => $eth,
		l3 => $ip,
		l4 => $l4,
	);
}
else
{
	$frame = Net::Packet::Frame->new(
		l3 => $ip,
		l4 => $l4,
	);
}

$frame->send;

# Note: if you have faked your address, don't expect a 
# reply!
if($transport eq 'tcp')
{
	until($dump->timeout)
	{
		if($frame->recv)
		{
			print $frame->reply->l3, "\n";
			print $frame->reply->l4, "\n";
			last;
		}
	}
}

# clean up crap files
$dump->stop;
$dump->clean;

# Handle command line args
sub handleArgs
{
	my @args = @_;
	my $argsLength = @args;

	if($argsLength < 6)
	{
		printUsage();
		die "Incorrect arguments\n";
	}
	else
	{
		for(my $i = 0; $i < $argsLength; $i++)
		{
			my $arg = $args[$i];

			switch($arg)
			{
				# Port to send to
				case "-p"
				{
					$port = $args[$i + 1];
					$i++;
				}
				# IP version number
				case "-v"
				{
					$version = $args[$i + 1];
					$i++;
				}
				# transport layer protocol
				case "-t"
				{
					$transport = $args[$i + 1];
					$i++;
				}
				case "-s"
				{
					$srcAddr = $args[$i + 1];
					$i++;
				}
				case "-d"
				{
					$dstAddr = $args[$i + 1];
					$i++;
				}
				case "-i"
				{
					$if = $args[$i + 1];
					$i++;
				}
				else
				{
					printUsage();
				}
			}
		}
	}
}

sub printUsage
{
	print("USAGE: \n" . 
		  "sendPacket [-v 4|6] [-t tcp|udp] [-s srcAddr]\n" .
		  "-i iface -p dstPort  -d dstAddr\n");
}

sub printEnv
{
	print("transport: $transport\n");
	print("port:  $port\n");
	print("version:  $version\n");
	print("srcAddr: $srcAddr\n");
	print("dstAddr: $dstAddr\n");
	print("if: $if\n");

}

##</code><code>##

sudo ./sendPacket.pl -v 4 -t tcp -s 192.168.1.93 -i eth0 -p 25 -d 192.168.1.90

##</code><code>##

sudo ./sendPacket.pl -v 6 -t tcp -s fe80::21c:23ff:fefe:5b7e -i eth0 -p 25 -d fe80::2b0:d0ff:fe7b:bcae