Wireshark-dev: Re: [Wireshark-dev] Checksum filterable fields
From: Christopher Maynard <[email protected]>
Date: Thu, 27 Jun 2013 19:36:10 +0000 (UTC)
 <[email protected]> writes:

> Perhaps all checksum validations could be an enumeration of 
> "-1" (or "2"?) - unknown/disabled
> "0" - good
> "1" - bad

The TCP dissector does something similar for the window scaling factor.  If
the 3-way handshake isn't captured, then the scaling factor is unknown and
set to -1.  So, there is some precedence at indicating unknown values using
-1, and if changes are to be made, then -1 would be my vote.

> If we're already going to take a hit with changed display filter names in
the name of consistency, why not go all the way?

I like consistency, so it's fine by me.  Just my 2 cents though.

Removing the bad_checksums does have at least 1 drawback though, and that's
that several of them are used in default coloring rules, so if they're
removed, users will likely end up with several warnings of the form:

Warn Could not compile color filter "Checksum Errors" from saved filters:
"<protocol>.checksum_bad" is neither a field nor a protocol name.