PHP/Network/socket create listen

Creates a ROT13 server when people connect to it and send text, it responds with the ROT13 equivalent of their text:

 
<?
    $socket = socket_create_listen("12345");
    if (!$socket) {
            print "Failed to create socket!\n";
            exit;
    }
    while (true) {
            $client = socket_accept($socket);
            $welcome = "\nWelcome\n";
            socket_write($client, $welcome);
            while (true) {
                    $input = trim(socket_read ($client, 256));
                    if ($input =  = "!close") {
                            break;
                    }
                    if ($input =  = "!halt") {
                            socket_close ($client);
                            break 2;
                    }
                    $output = str_rot13($input) . "\n";
                    socket_write($client, $output);
                    print "Them: $input, Us: $output\n";
            }
            socket_close ($client);
    }
    socket_close ($socket);
?>