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After discussing with Yee and Booker it was seen that forks may be too complicated. The version of Perl at SLAC did not support threading. Also the security people will not allow forks running inside a CGI-script. So I had to come up with an alternative. The solution to this problem was to use Asyncronous Asynchronous IO. A buch bunch of requests could be send to the landmarks without waiting for he response. The LWP::Parallel library provides all this functionality. It supports asyncronous asynchronous IO. Currently it is not installed so I am using a local version in my home directory. Ultimately this module has to be installed on the production server.
I have implemented most of the functionality. The script is running fine. I will have to taken measures to make the script more secure so that it could not be used as a platform to launch DDOS attacks, by limiting the number of concurrent process of reflector.cgi to 10. Also the script produces customized messages such as ( request time out or Connection failed so that TULIP client can differentiate between the various kind of error conditions). Also there is a blacklisting mechanism so that particular IP addresses can be blocked.
The Script is deployed at /afs/slac.stanford.edu/g/www/cgi-wrap-bin/net/shahryar/smokeping/reflector.cgi
Sample Scripts
traceroute.pl: This script has been written with special security considerations so it will help in implementing reflector.cgi
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