Log file format

I set up m0n0wall about two months ago, and configured it to forward 
syslog to a server on my LAN. I now have seven weeks of log files that I 
would like to examine. I have started sketching out some Perl scripts to 
analyze them, but I cannot find any documentation on the format of those 
lines. Did I miss it somewhere? What do the fields mean and what is the 
full set of flag values that I need to look for?

Thank you,

Bob McConnell
N2SPP