/usr/share/doc/denyhosts/examples/plugins/shorewall_deny.sh is in denyhosts 2.10-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 | #!/bin/sh
#
# Stéphane LeDauphin <stephane@gaelane.org>
#
/sbin/shorewall reject $1
|