Ethereal-dev: Re: [Ethereal-dev] items with and without filterable fields in H.248

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Date: Thu, 12 May 2005 16:10:38 +0200
I found the reason, a very simple one.

the MGC encoded the "$" context as a 5 octet integer (00:ff:ff:ff:fe)
so it was not added to the tree as an uint, but just added a text
label. Exact same issue with the termination IDs that did not show as
filterable.

another issue is that  in  this exact case:

dissect_ber_integer(impl_tag,pinfo,tree,tvb,offset,&val);

does not set val, which might very well used uninitialized afterwards
even if the compiler believe it was and so it doesn't warn.


On 5/12/05, Anders Broman (AL/EAB) <anders.broman@xxxxxxxxxxxx> wrote:
> Hi,
> I had a quick look at a sample I have and could not see the problem. can you send me a file with the problem so I can have a look.
> Best regards
> Anders
> 
> -----Original Message-----
> From: ethereal-dev-bounces@xxxxxxxxxxxx
> [mailto:ethereal-dev-bounces@xxxxxxxxxxxx]On Behalf Of LEGO
> Sent: den 11 maj 2005 18:46
> To: Ethereal development
> Subject: [Ethereal-dev] items with and without filterable fields in
> H.248
> 
> While analyzing some traces containing BER encoded H.248 I noticed
> that some items are not added to the tree the same way for every
> packet.
> 
> For instance, in transactions initiated by the MGC the transactionId
> is filterable while it is not for those initiated by the MGw. They are
> both parsed correctly but just some ones are filterable. Something
> similar happens to terminationIds  for some types of terminations they
> are filtrable for some others they aren't.
> 
> I'm interested in fixing this, but I don't have yet the knowledge
> about asn.1 generated dissectors to cope with the issue. So, I have
> some questions:
> 
> Why this could happen?
> What should I be looking for in order to fix it?
> 
> Thanks,
> 
> Luis
> 
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> 


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