IO::Select is what you need. This will allow you to perform a non-blocking wait on the socket.

use IO::Select;

use constant TIMEOUT => 10;

...
...
my $select = IO::Select->new();
$select->add($con);  # from your example above.

# Don't need to save the array returned, there's only one handle.
if($select->can_read(TIMEOUT)) {
   # $con has pending data.
}
else {
   # timeout.
}
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