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Wireshark-dev: Re: [Wireshark-dev] SCTP De-chunking support

From: Michael Tuexen <Michael.Tuexen@xxxxxxxxxxxxxxxxx>
Date: Fri, 11 Jan 2013 14:41:56 +0100
On Jan 11, 2013, at 5:50 AM, vineeth vijay wrote:

> Hi,
> 
> I understood the idea. It would help in easier detection of the relevant upper layer info in large packets.
OK.
> What i would like to know is how it could be implemented. Setting some sort of flag for the filter specific chunk bytes, so that GUI/GTK colors it differently? Sorry, but i am not much familiar with GTK. 
Neither me... But I guess one has to mark the protocol tree entry for the protocol
which has the matching field. When displaying the tree element one has to draw
it with a specific color.

I can see if it can be implemented (knowing someone knowing the GTK stuff...).

Best regards
Michael
> 
> Vineeth
> 
> On Fri, Jan 11, 2013 at 4:08 AM, Michael Tuexen <Michael.Tuexen@xxxxxxxxxxxxxxxxx> wrote:
> On Jan 10, 2013, at 9:44 PM, vineeth vijay wrote:
> 
> > Hi,
> >
> > Yes, highlighting would work too. Ultimately the application info corresponding to display filter should be visible easily without the need to scroll through the entire frame. Any suggestions on how to achieve this?
> > I think GUI coloring implementation would paint the entire frame with the same color,wouldn't it?
> No, what I mean is the following:
> Assume you have an SCTP packet with 5 DATA chunks each containing an M3UA message.
> The packet is shown because you filtered for a field in the third M3UA message.
> Then only the third M3UA part would be colored specifically. The rest of the
> packet is shown, but not in this color. Do you get the idea from my description?
> Would that address your issue?
> 
> Best regards
> Michael
> >
> > Vineeth
> >
> > On Fri, Jan 11, 2013 at 1:44 AM, Michael Tuexen <Michael.Tuexen@xxxxxxxxxxxxxxxxx> wrote:
> >
> > On Jan 10, 2013, at 8:49 PM, vineeth vijay wrote:
> >
> > > Hi,
> > >
> > > > Dissection is fine. What I was wondering is whether it is possible to show these individual data chunks as separate frames themselves.
> > > >But they are in the same frame. I really prefer not to show them in a way they
> > > have not been on the wire.
> > >
> > > Basically agreed on the above point.  Changing the default behavior may not be good due to all the copied lower layer bytes and resulting increase in the size of capture in case there are 4-5 chunks per packet. But still feel it would be a nice optional feature to have when doing actual offline analysis.
> > I do understand that it is sometimes hard to find the application layer packet when using display
> > filters and there are multiple application layer packets bundled in a single frame. I also have
> > traces with a large number of bundled chunks.
> > >
> > > > Hence, when i apply display filter ,  only the chunks with  exact matches should be visible. Is this supported currently?
> > > >No. Filtering is based on packets. Not sure how to improve that. We can't show 'half' of a packet.
> > > However, there might be ways to draw your attention to the upper layer packet which matches the
> > > filter.
> > > Regarding above point, would like to suggest that the packet information being displayed can be restricted to the PDU which actually matches the display filter. E.g out of an SCTP packet carrying 3-4 M3UA chunks, the pinfo of only the  chunk matching the filter can be displayed?
> > Thinking about this... What about displaying only the frames, which match a display filter (like today).
> > However, it might be helpful to highlight that part (like the M3UA packet) which matches the display filter.
> > This should allow to find the upper layer packet pretty fast. What do you think?
> >
> > Best regards
> > Michael
> > >
> > > Vineeth
> > >
> > > On Fri, Jan 11, 2013 at 12:54 AM, Michael Tuexen <Michael.Tuexen@xxxxxxxxxxxxxxxxx> wrote:
> > > On Jan 10, 2013, at 5:31 PM, vineeth vijay wrote:
> > >
> > > > Hi,
> > > >
> > > > Dissection is fine. What I was wondering is whether it is possible to show these individual data chunks as separate frames themselves.
> > > But they are in the same frame. I really prefer not to show them in a way they
> > > have not been on the wire.
> > > > Hence, when i apply display filter ,  only the chunks with  exact matches should be visible. Is this supported currently?
> > > No. Filtering is based on packets. Not sure how to improve that. We can't show 'half' of a packet.
> > > However, there might be ways to draw your attention to the upper layer packet which matches the
> > > filter.
> > >
> > > Best regards
> > > Michael
> > > > Currently , i use the below tool for this purpose:
> > > > http://frox25.no-ip.org/~mtve/wiki/SctpDechunk.html
> > > >
> > > > Regards,
> > > > Vineeth
> > > >
> > > > what problem are you trying to solve? Wireshark supports dissecting the upper layer paylaod
> > > > for bundled DATA chunks for ages...
> > > >
> > > > Best regards
> > > > Michael
> > > > >
> > > > > Vineeth
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