Wireshark-dev: Re: [Wireshark-dev] Dissector question

Date: Sun, 10 Mar 2013 13:49:54 -0400 (EDT)
I think you need a combination of a conversation and frame data.
 
Only on the first pass (!pinfo->fd->flags->visited), create and track the conversation. Also write the current sequence number to the frame data (p_add_proto_data).
On subsequence passes (pinfo->fd->flags->visited), just use the frame data you set earlier (p_get_proto_data).
tree will NULL on first pass (in Wireshark), but this logic should be "tree independent" and should just use the visited flag.
-----Original Message-----
From: David Arnold <davida@xxxxxxxxx>
To: Developer support list for Wireshark <wireshark-dev@xxxxxxxxxxxxx>
Sent: Sun, Mar 10, 2013 1:32 pm
Subject: Re: [Wireshark-dev] Dissector question

On 10/03/2013, at 5:13 PM, Evan Huus wrote:

Hi Evan,

Thanks for your help.

<...>

> I'm not sure I follow this. Can't you simply store the most recent
> sequence number in the conversation struct, and increment it for each
> PDU received?

I tried to do this, and perhaps I just got it (slightly) wrong.

In my foo_dissect() function, I looked up the conversation, grabbed the latest 
sequence number, incremented it, and wrote it back to the conversation.  I 
displayed it in the tree_item for the PDU, and in the COL_INFO, which was 
basically what I was after.

The issues I had seemed to be related to when my dissection function was called: 
if I scrolled from start to end of the capture, it was fine.  If I jumped to the 
final frame, the sequence number wasn't incremented for the intervening PDUs.

Perhaps I need it to be done outside my  if (tree) { ... } ?

Thanks again; any suggestions appreciated,



d




> 
> Evan
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