#!/usr/bin/perl

#Simples Server konstrukt by FlorianL;)

use strict;
require 5.002;
use warnings;
use IO::Socket;
use Carp;

my $cfgfile = "serverconfig.cfg";
my $keyfile = ".key.file";

my ($port, $username, $choosed, $coderef, $crypted);

sub logmsg {print "$0 $$: @_ at ", scalar localtime, "\n" }
sub spawn;

sub genpass {
    print ("\nGenerating KeyFile\nEnter your Password: ");
    chomp (my $password = <STDIN>);
    my @chars = ("A" .. "Z");
    my $salt = join("", @chars[ map {rand @chars } (1 .. 2) ]);
    $crypted = crypt("$password", "$salt");
    open(KEYFILE,">$keyfile") or die "Error: Cant write the Keyfile";
    print KEYFILE $crypted;
    close (KEYFILE);
    print ("\nHash = $crypted\n");
    system("chmod 666 $keyfile");
    print ("Keyfile saved to $keyfile!\nPermissions set to 666\nUpload it to your Clients now!\n");
}

sub readconfig() {
    open(CONFIG,$cfgfile) or die "Error: Cant open $cfgfile";
    my @config=<CONFIG>;
    close(CONFIG);
    chomp($port = $config[0]);
    if ($port eq "") { die ("Error: No Port specified"); }
    chomp($username = $config[1]);
        if ($username eq "") { die ("Error: No Username specified"); }
}

sub writeconfig() {
    print ("Config\n------\n");
    print ("\nPort: ");
    my $port = <STDIN>;
    if ($port =~ m/[a-z]+/) { die ("Port must be a number!"); }
        print ("\nUsername: ");
    my $username = <STDIN>;
    print ("Config written to $cfgfile\n");
    my @config = ($port, $username,);
    open(CONFIG,">$cfgfile");
    print CONFIG (@config);
    close (CONFIG);
    open(KEYFILE,">$keyfile");
    if (-z "$keyfile") {
        print ("No KeyFile present, well we generate one now...\n");
        genpass();
    } else {
        print ("KeyFile allready present!\n");
    }
    close(KEYFILE);
}

sub server() {
    readconfig();
    my $proto = getprotobyname('tcp');
    socket(SERVER, PF_INET, SOCK_STREAM, $proto)    || die "FAILED: socket: $!";
    setsockopt(SERVER, SOL_SOCKET, SO_REUSEADDR, pack ("l", 1))    || die "FAILED: setsockopt: $!";
    bind(SERVER, sockaddr_in($port, INADDR_ANY))    || die "FAILED: bind: $!";
    listen(SERVER, SOMAXCONN)    || die "FAILED: listen: $!";

    logmsg "Server started on Port $port";

    my $waitedpid = 0;
    my $paddr;

    sub KILLER {
            our $waitedpid = wait;
            $SIG{CHLD} = \&KILLER;
            logmsg "Killed $waitedpid" . ($? ? " with exit $?" : '');
    }
    $SIG{CHLD} = \&KILLER;
    for ($waitedpid = 0;
        ($paddr = accept(CLIENT,SERVER)) || $waitedpid;
        $waitedpid = 0, close CLIENT)
    {
        next if $waitedpid and not $paddr;
        my ($port,$iaddr) = sockaddr_in($paddr);
        my $name = gethostbyaddr($iaddr,AF_INET);

        logmsg "Connection from",inet_ntoa($iaddr);

    spawn sub {
        print "CONNECT\n";
        open(KEYFILE,$keyfile);
        my $crypt = <KEYFILE>;
        close(KEYFILE);
        my $authresponse = '';
        if ($authresponse eq $crypt) {
            print "AUTHED\n";
        } else {
            print "DENIED\n";
            }
        }
    }

    sub spawn {
        my $coderef = shift;
        unless (@_ == 0 && $coderef && ref($coderef) eq 'CODE') {
            confess "usage: spawn CODEREF";
        }
        my $pid;
        if (!defined($pid = fork)) {
            logmsg "cannot fork: $!";
            return;
        } elsif ($pid) {
            logmsg "forked $pid";
            return;
            }
        open (STDIN, "<&CLIENT")    || die "cant dup client to stdin";
        open (STDOUT, ">&CLIENT")    || die "cant dup client ti stdout";
        exit &$coderef();
        }
    }

sub help() {
    print ("Valid commandline Options are:\n");
    print ("-config        -Initiates Configuration\n");
    print ("-printcfg    -Print Config\n");
    print ("-server        -Starts the Server\n");
    print ("-genpass    -Generates a new keyfile \(1st-timers: Use -config instead!\)\n");
}

main {
$choosed = $ARGV[0];
if ($choosed eq '-config') {
        writeconfig();
        exit 0;
} elsif ($choosed eq '-printcfg') {
        readconfig();
    print ("Port: $port");
    print ("Username: $username");
        exit 0;
} elsif ($choosed eq '-genpass') {
        genpass();
        exit 0;
} elsif ($choosed eq '-server') {
        server();
        exit 0;
} else {
    help();
        exit 0;
    }
}

#!/usr/bin/perl

use strict;
use warnings;
use IO::Socket;

my ($server, $port, $keyfile, $choosed);

sub readconfig() {
    open(CONFIG,"config.cfg") or die "Error: Cant open config.cfg";
    my @config=<CONFIG>;
    close(CONFIG);
    chomp($server = $config[0]);
        if ($server eq "") { die ("Error: No Server specified"); }
    chomp($port = $config[1]);
    if ($port eq "") { die ("Error: No Port specified"); }
    chomp($keyfile = $config[2]);
    if ($keyfile eq "") { die ("Error: No Keyfile specified"); }
}

sub writeconfig() {
    print ("Config\n------\n");
    print ("Server: ");
    my $server = <STDIN>;
    print ("\nPort: ");
    my $port = <STDIN>;
    if ($port =~ m/[a-z]+/) { die ("Port must be a number!"); }
        print ("\nKeyfile: ");
    my $keyfile = <STDIN>;
    print ("Config written to config.cfg\n");
    my @config = ($server, $port, $keyfile);
    open(CONFIG,">config.cfg");
    print CONFIG (@config);
    close (CONFIG);
}

sub connection() {
    readconfig();
    my $remote = IO::Socket::INET->new (
        Proto => 'tcp',
        PeerAddr => $server,
        PeerPort => $port,
        Reuse => 1,
    ) or die "$!n";
    print ("Connected to ", $remote->peerhost, " on port ",$remote->peerport, "\n\n");
    $remote->autoflush(1);
    while ($remote) {
        my $line = <$remote>;
        open(KEYFILE,$keyfile);
                my $crypt = <KEYFILE>;
                close(KEYFILE);
        if ($remote eq 'AUTH') {
            print $remote "$crypt";
        } elsif ($remote eq 'AUTHED') {
            print $remote "TEST";
        } else {
            print "Communication failed, exiting...\n";
            exit;
        }
    }
    close $remote;
}


sub help() {
    print ("Valid commandline Options are:\n");
    print ("-config        -Initiates Configuration\n");
    print ("-printcfg    -Print Config\n");
    print ("-connect    -Connects to the Server\n");
}

$choosed = $ARGV[0];
if ($choosed eq '-config') {
        writeconfig();
        exit 0;
} elsif ($choosed eq '-printcfg') {
        readconfig();
    print ("Server: $server");
    print ("Port: $port");
    print ("Keyfile: $keyfile");
        exit 0;
} elsif ($choosed eq '-connect') {
        connection();
        exit 0;
} else {
    help();
        exit 0;
}

Server:

[root@doorgunner scripts]# perl server.pl -server
server.pl 18904: Server started on Port 1337 at Fri May 18 11:32:44 2007
server.pl 18904: Connection from 127.0.0.1 at Fri May 18 11:32:47 2007
server.pl 18904: forked 18906 at Fri May 18 11:32:47 2007
server.pl 18904: Killed 18906 with exit 256 at Fri May 18 11:32:47 2007
[root@doorgunner scripts]#

Client:

[root@doorgunner scripts]# perl client.pl -connect
Connected to 127.0.0.1 on port 1337

Communication failed, exiting...
[root@doorgunner scripts]#


Netcat:

[root@doorgunner scripts]# nc localhost 1337
CONNECT
DENIED
[root@doorgunner scripts]#