Wireshark · Ethereal-dev: Re: [Ethereal-dev] First cut at H.450 dissector

[Guy Harris <guy@xxxxxxxxxxxx>]

On Sep 23, 2003, at 4:58 AM, Graeme Reid wrote:

> Inspired by the new H.225 and H.245 dissectors supplied by Andreas 
> Sikkema (andreas.sikkema@xxxxxxxxxxx),
> I have taken a first cut at an H.450 dissector.  It currently handles 
> H.450.1 and H.450.2 messages.  At this stage, it has only been tested 
> using Blind Transfer success and failure cases, but Consultation 
> Transfer should also work.
> Unfortunately I have run out of time to work on it further (at least 
> in the short-term) so I thought it better to post what I have done so 
> far.

I assume that's why I get the warning

	packet-h450.c:354: warning: `Extension_vals' defined but not used

i.e., the code to use it hasn't been written yet.


>   The only known problem with it so far is that an invoke Id in a 
> return result or return error of >32k
> will be displayed as a negative number.

Well, the constrained invokeId is an unsigned integer (FT_UINT32), but 
the other invokeID is signed (FT_INT32), so values with the uppermost 
bit set will be treated as negative numbers.

The first of those is handled by "dissect_per_constrained_integer()", 
which treats the integer as unsigned.  The latter is handled by 
"dissect_per_integer()", which treats it as signed; I don't have any of 
the ASN.1 specs handy, so I don't know whether there needs to be, for 
example, a "dissect_per_unsigned_integer()" routine.

> There is one new file plus the diffs below.

Checked in (along with an update to Makefile.am).