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Implementation
There are two scripts: reflector.cgiand EventHandler.pm. Both have -T (Tainting), warning (-w), use strict, use the 3 parameter version of open, all opens and closes have a die or its equivalent. EventHandler.pm is called by reflector.cgi. The Scripts are deployed in the path /afs/slac.stanford.edu/g/www/cgi-wrap-bin/net/shahryar/smokeping/.
Invocation
The reflector script is called by a URL of the form:
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The ability parameter enables the user to specify whether to use enabled landmarks (ability=1, default) or disabled landmarks (by specifying ability=0). The enabled landmarks are found in;
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http://www.slac.stanford.edu/comp/net/wan-mon/tulip/sites.xml |
The disabled landmarks are found in:
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http://www.slac.stanford.edu/comp/net/wan-mon/tulip/sites-disabled.xml |
The sites xml files are created a by a trscrontanb running in pinger@pinger.slac.stanford.edu. The script that writes sites.xml is: /afs/slac/package/pinger/tulip/create_sites-xml.plThere pl. There is also a debug parameter. Use debug=1 or greater if you want debugging output.
The function parameter, enables one to specify to ping (function=ping, default), to print out usage information (function=help), to print out the log file(function=log), and to analyze the log file (funjction=analyze)function=analyze). The function analyze has a sub option ability=0 to analyze the logs for disabled landmarks and ability =1 (default) to analyze log entries excluding those for disabled landmarks.
The script uses asynchronous I/O to talk simultaneously with up to 20 landmarks. Up to 5 copies of reflector.cgi can be running simultaneously.
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There are about 60 SLAC/Looking Glass landmarks, and about 156 PlanetLabs landmarks. We are working on filtering the latter to remove non- or poorly respodning responding landmarks. The PlanetLab landmarks send 10 pings very quickly, whereas the SLAC/Looking Glass landmarks send five 56 byte pings with one second between them, they will also wait for a deadline time of 30 seconds for pings to be replied to.
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