ddns-hostname filtering before DDNS

[Chris Deiss]

I'd like to perform something equivalent to:

ddns-hostname =~ s/[^a-zA-Z0-9\-]/\-/g;

before the DDNS operation occurs between dhcpd and BIND.

I have a number of DHCP clients sending weird hostname or dhcp-client- 
identifier values that violate BIND's check-names setting (which I  
need).

Any suggestions?  Would the execute() dhcp-eval expression somehow  
work?  Or 'on commit' in some horrendous form?

Thanks!
Chris