Ethereal-dev: RE: [ethereal-dev] per frame data / conversations

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From: Jeff Foster <jfoste@xxxxxxxxxxxx>
Date: Fri, 22 Sep 2000 09:02:01 -0500

Per Richard Sharpe

> At 07:52 AM 9/22/00 -0500, Frank Singleton wrote:
>
> >I generally capture all, then run dispaly filters , or sometimes
> >I use display filters while capturing.
> >
> >Can I still do this if I implement conversations, according to the
> >above comments. Or is there something else more applicable.


> The approach that I think has to be taken is the following:
> 
>   1. The initial pass through the packets uses a conversation to 
>      accumulate all the info it needs during subsequent passes.
> 
>   2. For each packet during the initial pass, save any info in per
>      packet data that cannot be easily re-computed, or which depends on
>      previous packets. This is required when the user jumps all over
>      the place.
> 
>   3. On subsequent access to packets, check for per-packet/frame data
>      first and use that if it exists, else use what is in the 
>      conversation and what you can dissect.
> 
>   4. If a rescan occurs, it does not matter, because the conversation
>      stuff is blown away, as is the per-frame data, so you start over 
>      again as if it were the first time.

Excellent advice.  The only thing I would add is to use the 
frame_data flags.visited to see if this is the initial pass and 
the packet hasn't been dissected yet.


Jeff Foster
jfoste@xxxxxxxxxxxx