#!/usr/bin/perl

use strict;
use warnings;


my($maccnt, $pps, $src, $dest) = @ARGV;

usage() if !defined $dest;

if ( $maccnt !~ /^\d+$/ || $maccnt < 1 ) {
	print STDERR "MAC count must be a positive integer\n";
	exit 1;
}

if ( $pps !~ /^\d+$/ || $pps < 1 ) {
	print STDERR "packets/sec must be a positive integer\n";
	exit 1;
}

if ( $src !~ /^(\d+\.\d+\.\d+\.\d+)$/ ) {
	print STDERR "source IP must be a valid IPv4 address\n";
	exit 1;
}

if ( $dest !~ /^(\d+\.\d+\.\d+\.\d+)$/ ) {
	print STDERR "destination IP must be a valid IPv4 address\n";
	exit 1;
}

main($maccnt, $pps, $src, $dest);

sub usage {
	print STDERR "DHCP Flood using option 82\n";
	print STDERR "This is only to test dhcp_protect, the DHCP packets aren't really valid\n";
	print STDERR "DO NOT SEND THIS TO YOUR DHCP SERVER !!!!\n";
	print STDERR "\n";
	print STDERR "Usage: $0 <MAC count> <packets/sec> <source IPv4> <destination IPv4>\n";
	print STDERR "Dependency: nemesis must be installed\n";
	print STDERR "https://ftp.troglobit.com/nemesis/\n";
	print STDERR "\n";
	exit 1;
}


sub main {
	my($maccnt, $pps, $src, $dest)=@_;
	my $hdr = "";

	$hdr .= "010106010c02385600010000000000000000000000000000c16e5f43409c28db";
	$hdr .= "d56c000000000000000000000000000000000000000000000000000000000000";
	$hdr .= "0000000000000000000000000000000000000000000000000000000000000000";
	$hdr .= "0000000000000000000000000000000000000000000000000000000000000000";
	$hdr .= "0000000000000000000000000000000000000000000000000000000000000000";
	$hdr .= "0000000000000000000000000000000000000000000000000000000000000000";
	$hdr .= "0000000000000000000000000000000000000000000000000000000000000000";
	$hdr .= "000000000000000000000000638253633501013707017903060f77fc390205dc";
	$hdr .= "3d0701409c28dbd56c33040076a7000c097370616c6569666f6e000000000000";
	$hdr .= "0000000000000000000000520e0104000000000206XXXXXXXXXXXXff00000000";

	my $int = 1/$pps;

	while(1) {
		for(my $i=0; $i<$maccnt; $i++) {
			my $mac = sprintf("000000%06x", $i);
			my $pkt = $hdr;
			$pkt =~ s/XXXXXXXXXXXX/$mac/;
	
			open(N,"| nemesis udp -S $src -D $dest -x 67 -y 666 -i $int -P -") || die "install nemesis!";
			print N pack("H*",$pkt);
			print N "";
			close(N);
		}
	}
}