#!/usr/bin/perl
# serverfork.pl - a server that forks a child
# process to handle client connections
# use strict;
use IO::Socket;
use Sys::Hostname;
use POSIX qw(:sys_wait_h);
use Crypt::CBC;
sub REAP {
    1 until (-1 == waitpid(-1, WNOHANG));
    $SIG{CHLD} = \&REAP;
}
$SIG{CHLD} = \&REAP;
my $sock = new IO::Socket::INET(
                   LocalHost => 'localhost',
                   LocalPort => 9000,
                   Proto     => 'tcp',
                   Listen    => SOMAXCONN,
                   Reuse     => 1);
$sock or die "no socket :$!";
# STDOUT->autoflush(1);
my $cipher = Crypt::CBC->new( -key    => '1234',
			-cipher => 'Blowfish'
			);
my($new_sock, $buf, $kid);
while ($new_sock = $sock->accept()) {
    # execute a fork, if this is
    # the parent, its work is done,
    # go straight to continue
    next if $kid = fork;
    die "fork: $!" unless defined $kid;
    # child now...
    # close the server - not needed
    close $sock;

    while (defined($buf = <$new_sock>)) {
      chop $buf;
      server();
    }
    exit;
} continue {
    # parent closes the client since
    # it is not needed
    close $new_sock;
}

sub server {
my $plaintext = $cipher->decrypt($buf);
my $in = "SERVER: Text: ".$plaintext;
my $ciphertext = $cipher->encrypt($in);
print($new_sock $ciphertext);
}

##</code><code>##

#!/usr/bin/perl
# use IO::Socket;
use Crypt::CBC;
my $sock = new IO::Socket::INET(
                   PeerAddr => 'localhost',
                   PeerPort => 9000,
                   Proto     => 'tcp');
$sock or die "no socket :$!";
my $cipher = Crypt::CBC->new( -key    => '1234',
                             -cipher => 'Blowfish'
                            );
# clientfork.pl - a client that forks to
# read from STDIN and write to a server
use strict;
use IO::Socket;
my $host = shift || 'localhost';
my $port = shift || 9000;
my $sock = new IO::Socket::INET(
                   PeerAddr => $host,
                   PeerPort => $port,
                   Proto    => 'tcp');
$sock or die "no socket :$!";
$sock->autoflush(1);
my($in, $buf, $kid);
die "fork fail: $!" unless defined($kid = fork);
if ($kid) {
    # parent reads from STDIN, prints to socket
    while (defined($in = <STDIN>)) {
    my $ciphertext = $cipher->encrypt($in);
    print $ciphertext;
   print $sock $ciphertext;
    }
    # kill the child process
    kill(TERM => $kid);
} else {
    # child reads from socket, prints to STDOUT
    while (defined($buf = <$sock>)) {
      my $plaintext = $cipher->decrypt($buf);
   print $plaintext;
    }
    close $sock;
}

##</code><code>##

wmp@innocence:~/ISS/iss/daemon$ ./server.pl
Ciphertext does not begin with a valid header for 'salt' header mode at ./server.pl line 48
wmp@innocence:~/ISS/iss/daemon$