Ethereal-dev: Re: [Ethereal-dev] Use of tcp_dissect_pdu and tvb_format_text

Note: This archive is from the project's previous web site, ethereal.com. This list is no longer active.

Date Index Thread Index Other Months All Mailing Lists
Date Prev Date Next Thread Prev Thread Next
From: Guy Harris <guy@xxxxxxxxxxxx>
Date: Fri, 23 Jan 2004 01:12:20 -0800
On Fri, Jan 23, 2004 at 08:48:38AM -0000, CNS - Matthew Bradley wrote:
> Matthew: No, when I wrote the email but I stumbled across this before
> receiving your message. Can we add something to this effect to the
> README.developer section about tcp_dissect_pdus.

It's an issue for *all* TCP dissectors that do reassembly, even if they
don't use "tcp_dissect_pdus()".

It might also belong as a FAQ, as users not writing dissectors also run
across it.

> Now if I turn off the "Allow subdissector to desegment TCP streams"
> preference for TCP?, I get my "Short Frame" error. How can I check if this
> preference is set?

You can't.  If the user turns that option off, reassembly won't be done
- which is as it should be.  The error shouldn't be "Short Frame"; that
happens on some occasions, not all of which are, I think, associated
with TCP reassembly.  Part of the problem might, I think, be due to
requiring multiple lengths for tvbuffs, such as "size the packet would
have been had it been reassembled".

> Tvb_reported_length_Remaining still returns the reassembled length.

Given that reassembly isn't being done, that would be a bug.