Hi everyone,

I created a multithreaded port scanner. It's not perfect yet, so that's why I am asking for help here. :)

First of, is there a way to increase the scanningspeed besides using more threads? Now I create a sock with a 2 secs timeout.

I've also got some questions concerning the threading.
I made two versions:

1. This script gives an ip to a thread make and then the thread checks it. Afterwards the thread closes and new ones are created.
I think I have a memory leak here. The size is about 200mb with 20 threads and it keeps on rising.
Any idea how this is caused?

use IO::Socket;
use threads;
use threads::shared;
use warnings;

$0 =~ s/.*\\//;

die "usage: $0 <-p/-web/-ban> <port> <first_ip> <second_ip> <threads>\
+n" unless ($ARGV[4]);

$choice = $ARGV[0];
$port = $ARGV[1];
$first = $ARGV[2];
$second = $ARGV[3];
$maxthreads = $ARGV[4];

unless ($choice =~ /^-p$|^-web$|^-ban$/) {
    die "usage: $0 <-p/-web/-ban> <port> <first_ip> <second_ip> <threa
+ds>\n";
}

my $threads : shared = 0;
my $found : shared = 0;
my $count : shared = 0;

open(OUTPUT,">>pscan.txt");

OUTPUT->autoflush(1);
STDOUT->autoflush(1);

$f = inet_aton($first);
$s = inet_aton($second);
$f_ip = unpack('N', $f);
$s_ip = unpack('N', $s);
for ($o = $f_ip; $o < $s_ip; $o++) {
    $o = pack('N', $o);
    $ip = inet_ntoa($o);
    push @range, $ip;
    $o = unpack( 'N', $o );
}

$size = @range-1; 

for ($i = 0; $i <= $size; $i++) { 
    while (1) { 
        if ($threads < $maxthreads) {
            last unless defined($range[$i]);
            $thr = threads->create(\&scan, $range[$i]);
            $thr->detach();
            $percent = ($count/$size)*100;
            $percent = sprintf("%.1f", $percent);
            print "THREADS: $threads || STATUS: $percent% || FOUND: $f
+ound\t\r";
            last;
        } 
        else { 
            sleep(1); 
        } 
    } 
}

while ($threads > 0) { 
    print "THREADS: $threads || STATUS: 100% || FOUND: $found\t\r";
    sleep(1);
} 

close(OUTPUT);

print "THREADS: $threads || STATUS: 100% || FOUND: $found\t\r";

exit;

sub scan() {
    {lock($count);$count++;}
    {lock($threads);$threads++;}
    
    $sock = new IO::Socket::INET (PeerAddr => $_[0],PeerPort => $port,
+ Proto => "tcp", Timeout => 2);
    if ($sock) {
        if ($choice =~ /^-p$/) {
            {lock($found);$found++;}
            print OUTPUT $_[0].":".$port."\n";
        }
        elsif ($choice =~ /^-web$/) {
            print $sock "HEAD / HTTP/1.0\012\012";
            while (<$sock>) {
                chomp($_);
                if ($_ =~ /^Server: (.*)$/) {
                    {lock($found);$found++;}
                    $ban = $1;
                    chomp($ban);
                    $ban =~ s/\n|\r//g;
                    print OUTPUT $_[0].":".$port." [".$ban."]\n";
                    last;
                }
            }
        }
        elsif ($choice =~ /^-ban$/) {
            {lock($found);$found++;}
            print $sock "GET / HTTP/1.0\n\n";
            while (<$sock>) {
                chomp($_);
                $_ =~ s/\n|\r//g;
                print OUTPUT $_[0].":".$port." [".$_."]\n";
                last;
            }
        }
        close $sock;
    }
    
    {lock($threads);$threads--;}
}
[download]

2. This script creates the amount of threads given and every threads takes and checks an ip. So no new threads are created.
This way my memory doesn't increase and it's also not that high.
The problem is with the procentage I can't get right. Within the "while" loop the $count number is correct. But when I use $count outside the loop it adds some extra numbers, actually the number of amount of threads I started.
With for example 5 threads the count goes like this:

0
0
0
0
0
1
2
3
4
5
6
...
[download]

use IO::Socket;
use threads;
use threads::shared;
use warnings;

$0 =~ s/.*\\//;

die "usage: $0 <-p/-web/-ban> <port> <first_ip> <second_ip> <threads>\
+n" unless ($ARGV[4]);

$choice = $ARGV[0];
$port = $ARGV[1];
$first = $ARGV[2];
$second = $ARGV[3];
$maxthreads = $ARGV[4];

unless ($choice =~ /^-p$|^-web$|^-ban$/) {
    die "usage: $0 <-p/-web/-ban> <port> <first_ip> <second_ip> <threa
+ds>\n";
}

my $threads : shared = 0;
my $found : shared = 0;
my $count : shared = 0;

open(OUTPUT,">>pscan.txt");

OUTPUT->autoflush(1);
STDOUT->autoflush(1);

$f = inet_aton($first);
$s = inet_aton($second);
$f_ip = unpack('N', $f);
$s_ip = unpack('N', $s);
for ($o = $f_ip; $o < $s_ip; $o++) {
    $o = pack('N', $o);
    $ip = inet_ntoa($o);
    push @range, $ip;
    $o = unpack( 'N', $o );
}

$size = @range-1;

for ($i = 1; $i <= $maxthreads; $i++) {
    $thr = threads->create(\&scan);
    $thr->detach();
}

while ($threads > 0) {
    $percent = ($count/$size)*100;
    $percent = sprintf("%.1f", $percent);
    print "THREADS: $threads || STATUS: $percent% || FOUND: $found\t\r
+";
} 

close(OUTPUT);

print "THREADS: $threads || STATUS: $percent% || FOUND: $found\t\r";

exit;

sub scan() {
    {lock($threads);$threads++;}
    
    while($count <= $size) {
        unless (defined($range[$count])) {
            {lock($count);$count++;}
            next;
        }

        $sock = new IO::Socket::INET (PeerAddr => $range[$count],PeerP
+ort => $port, Proto => "tcp", Timeout => 2);
        
        if ($sock) {
            if ($choice =~ /^-p$/) {
                {lock($found);$found++;}
                print OUTPUT $range[$count].":".$port."\n";
            }
            elsif ($choice =~ /^-web$/) {
                print $sock "HEAD / HTTP/1.0\012\012";
                while (<$sock>) {
                    chomp($_);
                    if ($_ =~ /^Server: (.*)$/) {
                        {lock($found);$found++;}
                        $ban = $1;
                        chomp($ban);
                        $ban =~ s/\n|\r//g;
                        print OUTPUT $range[$count].":".$port." [".$ba
+n."]\n";
                        last;
                    }
                }
            }
            elsif ($choice =~ /^-ban$/) {
                {lock($found);$found++;}
                print $sock "GET / HTTP/1.0\n\n";
                while (<$sock>) {
                    chomp($_);
                    $_ =~ s/\n|\r//g;
                    print OUTPUT $range[$count].":".$port." [".$_."]\n
+";
                    last;
                }
            }
            close $sock;
        }
        
        {lock($count);$count++;}
    }
    
    {lock($threads);$threads--;}
}
[download]

Thx in advance