Re: A puzzled maintainer with questions regarding DLT_ values

["M.Baris Demiray" <barisdemiray () gmail com>]

Hello again,

I have solved almost all the problems that I mentioned below and now I
am sure that I should ask for a new DLT value for STANAG 5066 [1] MAC
(Medium Access Control Sublayer) PDUs. Currently I am able to dissect
these PDUs using DLT number 147 (USER0) using Wireshark 1.4.3 and I'd
like to have this dissector and corresponding DLT value in the main
stream.

I might add that STANAG 5066 SIS layer is already defined in Wireshark
[2] yet it can only dissect the packets transferred between STANAG
5066 and its clients. Now, what I propose is to have the same
functionality for the interface between STANAG 5066 and HF modem as
well. What else should I provide regarding this protocol to ask for a
DLT value?

Cheers,

[1] http://en.wikipedia.org/wiki/STANAG_5066
[2] http://wiki.wireshark.org/STANAG_5066

On Wed, Jan 19, 2011 at 9:02 AM, M.Baris Demiray <barisdemiray () gmail com> wrote:
> Hello,
>
> I've a couple of questions regarding dissector development and DLT_
> values and I hope I know enough to express myself.
>
> First of all, we're developing radio communication software,
> particularly STANAG 5066. Alongside the serial interface for the modem
> interface our implementation also has a socket interface for testing
> purposes.
>
> Now we have the need of saving STANAG 5066 PDUs into .pcap files to
> analyze them later using our experimental STANAG 5066 DPDU (Data
> Transfer Sublayer PDU) dissector. My ex-colleague, who wrote the
> dissector, wrote it for the purpose of dissecting DPDUs captured from
> the socket interface with prepending TCP header. But I, as the new
> maintainer of this dissector, need to dissect raw STANAG 5066 PDUs now
> since I modified the Data Transfer Sublayer (of STANAG 5066)  to
> maintain a .pcap file and to save incoming DPDUs into this file with
> relevant record headers. But, at this point, I'm stuck since when I to
> open this .pcap file using Ethereal (this is not because I'm against
> updates but because the system is offline) it successfully displays
> the packets yet when I attempt to "Decode " these packets "As..." I
> can't because that menu item is grayed out.
>
> By the way, I intuitively modified the dissector to make it use
> dissect_s5066dts() method rather than dissect_s5066dts_tcp() upon
> registering itself since I want it to dissect STANAG 5066 PDUs without
> any other prepending protocol headers. So I tried to place a couple of
> DLT_ values (such as DLT_USER0) into the global header's network field
> with no luck. At this point, should I ask for a new DLT_ value for
> PDUs which start with 0x90EB sync. sequence and without any other
> prepending header?
>
> Please feel free to ask for further information, or to correct my
> terminology, or to offer a different way of doing this.
>
> Cheers,
>
> PS: As soon as I ensure that I have a robust-enough dissector it will
> be sent as a patch.
>
> --
> M. Baris Demiray

-- 
M. Baris Demiray
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