Wireshark mailing list archives

Re: Calling MAC-LTE dissctor from lua dissector on the rest of te data


From: "Lehmann, Florian (EXT-Other - DE/Ulm)" <florian.lehmann.ext () nsn com>
Date: Thu, 19 Jan 2012 09:30:09 +0100

Hi Tony, Martin,

 

that did the trick, thanks a lot for your help and the example code.

 

BR,

Florian

 

From: wireshark-users-bounces () wireshark org
[mailto:wireshark-users-bounces () wireshark org] On Behalf Of ext Tony
Trinh
Sent: Thursday, January 19, 2012 2:42 AM
To: Community support list for Wireshark
Subject: Re: [Wireshark-users] Calling MAC-LTE dissctor from lua
dissector on the rest of te data

 

Your Lua is technically correct, but the MAC-LTE dissector cannot be
called directly because it relies on its heuristic dissector to be
called first. Perhaps Martin's upcoming changes will allow direct calls.

 

In the meantime, you can use the attached sample Lua as a workaround. It
parses a custom header from UDP packets on port 1111 and then indirectly
passes the remainder to the MAC-LTE heuristic dissector. If the PDU is
missing the required starter string ("mac-lte"), the script inserts it
into the buffer for you.

 

Remember to enable the MAC-LTE preference for "Try Heuristic LTE-MAC
over UDP framing". 

Example run:

 

$ tshark -r dummy-mac-lte.pcap -Xlua_script:proto_foo.lua

 

  1 0.000000000 192.168.1.130 -> 1.1.1.1      MAC-LTE 77 RAR (RA-RNTI=1,
SF=101) (RAPID=0: TA=0, UL-Grant=56332, Temp C-RNTI=8481) 

  2 0.000021000 192.168.1.130 -> 1.1.1.1      LTE RRC UL_CCCH 85 

  3 0.000029000 192.168.1.130 -> 1.1.1.1      MAC-LTE 73 DL: <CRC
Failed> UEId=0 NO-RNTI=0 Raw data (3 bytes)

  4 259.696665000 192.168.1.130 -> 1.1.1.1      MAC-LTE 70 RAR
(RA-RNTI=1, SF=101) (RAPID=0: TA=0, UL-Grant=56332, Temp C-RNTI=8481) 

  5 259.696684000 192.168.1.130 -> 1.1.1.1      LTE RRC UL_CCCH 78 

  6 259.696692000 192.168.1.130 -> 1.1.1.1      MAC-LTE 66 DL: <CRC
Failed> UEId=0 NO-RNTI=0 Raw data (3 bytes)

 

 

On Tue, Jan 17, 2012 at 5:51 AM, Lehmann, Florian (EXT-Other - DE/Ulm)
<florian.lehmann.ext () nsn com> wrote:

Hi All,

I hope this is the right place to ask as I can't find any helpful
information.
I have a simple UDP Protocol, which has a MAC-LTE packet embedded. After
dissecting my part of the packet, I would like to call the MAC-LTE
dissector on the rest of the data.

Calling the MAC-LTE dissector like:

local dissector = Dissector.get("mac-lte")
dissector:call(buffer(macPduDumpDataPos):tvb(), pinfo, subtree)

results in the following error message:
Can't dissect LTE MAC frame because no per-frame info was attached.

Could anyone point me in the right direction, how to dissect only the
header information from my custom protocol and to call the MAC-LTE
dissector afterwards?

I am using Wireshark version 1.5.1-RL30_110407 (SVN Rev 35697 from
/trunk).

Thanks and BR,
Florian


________________________________________________________________________
___
Sent via:    Wireshark-users mailing list
<wireshark-users () wireshark org>
Archives:    http://www.wireshark.org/lists/wireshark-users
Unsubscribe: https://wireshark.org/mailman/options/wireshark-users
 
mailto:wireshark-users-request () wireshark org?subject=unsubscribe

 

___________________________________________________________________________
Sent via:    Wireshark-users mailing list <wireshark-users () wireshark org>
Archives:    http://www.wireshark.org/lists/wireshark-users
Unsubscribe: https://wireshark.org/mailman/options/wireshark-users
             mailto:wireshark-users-request () wireshark org?subject=unsubscribe

Current thread: