use IO::Socket::INET;

use strict;

use constant MAX_CONN => 25;

$| ++;

my @connections;
my $request = "HEAD / HTTP/1.1\r\nConnection: Keep-Alive\r\nHost: www.google.com\r\n\r\n";

for (1..MAX_CONN) {
    $connections[$_]
        = new IO::Socket::INET(proto => "tcp",
            PeerAddr => "www.google.com",
            PeerPort => 80);
    print ".";
}
print "\n";

while (1) {
    my $sum = 0;
    for (1.. MAX_CONN) {
        my $buffer;
        if ($connections[$_]) {
            $sum ++;
            $connections[$_]->send($request);
            $buffer = "";
            while ($buffer !~ m/\r\n\r\n/) {
                my $piece;
                sysread($connections[$_], $piece, 10000);
                if ($piece eq "") {
                    $connections[$_]->close();
                    $connections[$_] = undef;
                    last;
                } else {
                    $buffer .= $piece;
                }
            }
        } else { #get those disconnected back
            $connections[$_]
            = new IO::Socket::INET(proto => "tcp",
                PeerAddr => "www.google.com",
                PeerPort => 80);
        }
    }
    print "there are $sum connections now\n";
}