You should look at using the "alarm" function to setup a timed alert - which can then be caught using eval.

You don't give much sample code, but this might be a good starting point:

#
#  Create a listening socket.
#


#
#  Never exit.
#
while (1)
{
    #
    #  Wait until we have an incoming connection
    #
    next unless $data = $main_socket->accept();

    #
    #  This eval block is here so that were can prevent DOS
    # attacks by closing sockets if there's nothing received.
    # after a while.
    #
    eval
    {
        # ten seconds.
        alarm( 10 );

        # read data
        $data->recv ($text,1000);
        
        # cancel timeout
        alarm( 0);
    };
    if ($@)
    {
        if ($@ =~ /timeout/)
        {
            # Timed out.  Close socket.  Exit.
            close($data);
            print "Timed out.\n";
        }
        else
        {
            # normal exit
            close( $data );
        }
    }
}
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