Hi,
Perhaps pcap-ng can be expanded to hold the metadata or the exported pdu
dlt.
Best regards
Anders

Den mån 29 sep. 2025 08:03wireshark via Wireshark-dev <
[email protected]> skrev:

> Hi Jaap,
>
>
> Your first remark is exactly why i started this topic. My case could be
> exotic, but there might also be other use cases i'm not aware of. If we're
> going to decide to make changes, whichever direction it goes, it's going to
> take more time and experience than i have on my own. If there is interest
> in such changes, i'm able to contribute quite some time, if there's no
> interest it's up to me to find other solutions for my use case and that's
> fine too.
>
> Next to my own use case i also see chances to improve analysis on other
> protocols like the ones that also do aggregation, but tunneling protocols
> might also benefit if the inner protocols are considered separate from the
> outer protocols.
>
>
> For your second remark, we already have tools to convert our files to
> pcap's as a workaround for some problems. The problem is that the frames
> contain a huge amount of metadata which is lost in such a conversion. Given
> the current state, finding where a converted frame was in the original file
> (to re-gain the metadata) is quite challenging.
>
> Best regards,
> Wesley
> ________________________________
> From: Jaap Keuter <[email protected]>
> Sent: Saturday, September 27, 2025 11:43:15 AM
> To: wireshark; Wireshark Deverloper Mailinglist
> Subject: Re: [Wireshark-dev] Multiple packets per frame
>
> Let op: Deze e-mail is van een externe afzender. Klik alleen op links en
> open bijlagen als je de afzender vertrouwt.
>
>
> Hi Wesley,
>
> So, we’re discussing reworking the whole of the core of Wireshark, to
> support a proprietary use case at this time. That is not to say that this
> is an interesting avenue to explore (I’ve got some other ideas about this
> too), but these changes are going to be invasive. I.e. the dissection
> engine, the tapping system doing the analysis, the filter system, the GUI
> which depends heavily on the packet list. On the other hand I think the
> more common use case is that of capturing on multiple interfaces at the
> same time, since that is the pcapng use case. So if anything, it should
> support that. All in all I think this is going to be time consuming, to say
> the least, and difficult to get right.
>
> Why not take a different approach to this challenge? You say that these
> files aren’t pcap files and have some private file handler. Apparently,
> from this file format and/or file handler it does become clear what the
> various blocks in the frames are. So why not pre-process these proprietary
> format files into proper pcapng files first and then load these into
> Wireshark? This 1) keeps all your information about the files/format etc.
> private, and 2) allows for the use of Wireshark as is Right Now.
>
> Thanks,
> Jaap
>
>
> > On 25 Sep 2025, at 10:50, wireshark via Wireshark-dev <
> [email protected]> wrote:
> >
> > Hi,
> >
> >
> > Thanks for being open to discuss this issue. I fully understand that not
> being able to share makes things difficult, but i hope we can find a way
> around that.
> >
> >
> > One idea i had is to implement the concept of subframes. This could be
> done by extending the packet_info struct with an array of pointers to
> packet_info struct's. In this way you could still pass it to dissectors,
> and dissectors could choose to add new subframes to the structure. This
> might have the least impact on all existing dissectors since they do not
> have to be aware of this.
> >
> > GUI-wise this could be displayed as "frame 1.1" (for frame 1, subframe
> 1) or as a tree like the
> >
> > packet details pane.
> >
> > Filters and other analysis would have to be altered to walk this tree of
> packets instead of a flat list.
> >
> >
> > @Eugene:
> >
> > Part of the problem is that the files aren't pcaps, hence the private
> file handler. The packet details pane is mostly quite useful and correct.
> RTP analysis shows the most problems so i'll use that as an example.
> >
> > Image one frame containing 100 IP packets carrying RTP data for both
> directions of a call. Part of the RTP analysis uses timestamps to calculate
> things like throughput, jitter, etc. But since the analysis uses the frame
> timestamp it thinks all RTP packets arrived within the same microsecond,
> which of course messes up the complete analysis. This also confuses the
> player when it tries to reassemble the audio stream.
> >
> > Also, because the packet_info struct only contains one set of IP
> addresses, it mixes up both directions because all packets seem to have the
> same source and destination.
> >
> > I'll have to ask what i can do with screenshots, that could take some
> time.
> >
> >
> > @Roland:
> >
> > I've checked the openSAFETY dissector and the example pcaps on the wiki,
> but i don't see something that looks like the issue i'm having. Maybe i'm
> not looking at the right place, the examples contain quite some frames. Is
> there a specific frame you are referring to?
> >
> > In the list archives i found a pcap with 802.11n traffic, this comes
> quite close to my case:
> >
> > https://lists.wireshark.org/archives/wireshark-dev/201704/msg00183.html
> >
> > Frame 3 shows the agreggation, especially the "IEEE 802.11 Aggregate
> MSDU" section. Also note what it does to the "Protocols in frame" field,
> which is technically correct but maybe not the most useful way to display
> it.
> >
> >
> > Best regards,
> >
> > Wesley
> >
> > ________________________________
> > From: Jaap Keuter <[email protected]>
> > Sent: Wednesday, September 24, 2025 9:14:48 AM
> > To: [email protected]
> > Cc: wireshark; [email protected]
> > Subject: Re: [Wireshark-dev] Re: Multiple packets per frame
> >
> >
> > Let op: Deze e-mail is van een externe afzender. Klik alleen op links en
> open bijlagen als je de afzender vertrouwt.
> >
> >
> > Hi,
> >
> > I think you are referring to this one:
> > https://lists.wireshark.org/archives/wireshark-dev/201710/msg00000.html
> >
> > Send from my iPhone
> >
> > On 23 Sep 2025, at 21:20, Roland Knall <[email protected]> wrote:
> >
> > 
> > Hi Eugene
> >
> > A very similar example for this is the way the openSAFETY dissector
> works. For that there are examples in the wireshark trace repository. Also,
> if you search through Wireshark-dev, there was a discussion ages ago
> between Evan Huus and myself and I also think Guy Harris, about what would
> be needed from a pure epan pov to achieve such a thing. (for instance, how
> would you handle duplicate information for the sub packages so that our
> other stuff like filters would still work correctly).
> >
> > I am all for pursuing that idea again.
> >
> > cheers
> >
> > Am Di., 23. Sept. 2025 um 21:11 Uhr schrieb Eugène Adell <
> [email protected]<mailto:[email protected]>>:
> > Hi Wesley,
> >
> > thanks for talking about this very particular use case. I understand
> > you cannot share any PCAP, even anonymized, which makes things
> > difficult to solve. Do you think that would be possible to share a
> > screenshot of the GUI, particularly of the Packet Details panel where
> > we can see how things are interpreted and rendered ? Even if some
> > parts are blurred or masked intentionally , that would help a lot.
> >
> > best regards
> > E.A.
> >
> > Le lun. 22 sept. 2025 à 14:13, wireshark via Wireshark-dev
> > <[email protected]<mailto:[email protected]>> a
> écrit :
> >>
> >> Hi All,
> >>
> >> I work for the Netherlands Forensic Institute (NFI, https://nfi.nl/ )
> where i maintain a wireshark fork for internal use with a custom dissector
> and file handler. Unfortunately i'm not allowed to share this code or a
> capture.
> >>
> >> We have a (special?) use case where each frame can contain a high
> number of IP packets, i've even seen up to 100's in one frame. Those
> packets may be related (same sender/receiver or reverse, same service), but
> don't need to be. For most things dissection works as expected. Especially
> in cases where analysis spans multiple packets this breaks, sometimes in
> minor ways, sometimes with an unusable result. The cause of this seems to
> be that on quite some places there is the assumption that 1 frame == 1 IP
> packet. So far I found two places where this is visible:
> >> 1) The packet_info struct is used per frame and can only hold one set
> of source/destination addresses and ports. In cases where more IP headers
> are available, the values of the last header that is analyzed will be the
> one that remain, the others are lost (at least in packet_info, not in the
> dissection tree of course).
> >> 2) When referring to other packets (like pairing a request and response
> or stream analysis) this is done by frame number only. Of course this is
> ambiguous when a frame holds 10's or 100's of packets.
> >> Because of this we run into multiple problems. TCP, QUIC and RTP are
> the first ones that come to mind. For some a workaround is a possible (like
> disabling TCP sequence number analysis), but others run into so much
> problems there is not much i can do to improve it.
> >>
> >> As far as i can see similar issues can also arise with dissectors
> available in public code. For example 802.11n and G.hn allow frame
> aggregation, although a bit more constrained than my case. For example
> 802.11n only allows aggregation of frames for the same destination MAC
> address. This might make it less visible, but it seems to be there none the
> less.
> >>
> >> I'd like to know if there is any interest to structurally solve these
> issues by removing this 1 frame == 1 IP packet assumption. As far as i can
> see that has quite some impact on wireshark, so that's probably something
> i'll need help with. But most important: Is there any interest to merge
> such changes?
> >>
> >> Best regards,
> >> Wesley
> >> ________________________________
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> >>
> >> Ministerie van Justitie en Veiligheid
> >>
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> >>
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> >
> > Ministerie van Justitie en Veiligheid
> >
> > This message may contain information that is not intended for you. If
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> you are requested to inform the sender and delete the message. The State
> accepts no liability for damage of any kind resulting from the risks
> inherent in the electronic transmission of messages.
> >
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>
> ________________________________
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> niet de geadresseerde bent of dit bericht abusievelijk aan u is
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> te verwijderen. De Staat aanvaardt geen aansprakelijkheid voor schade, van
> welke aard ook, die verband houdt met risico's verbonden aan het
> elektronisch verzenden van berichten.
>
> Ministerie van Justitie en Veiligheid
>
> This message may contain information that is not intended for you. If you
> are not the addressee or if this message was sent to you by mistake, you
> are requested to inform the sender and delete the message. The State
> accepts no liability for damage of any kind resulting from the risks
> inherent in the electronic transmission of messages.
>
> Ministry of Justice and Security
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