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Why aren't ITS messages supported yet? [closed]

asked 2019-02-28 16:56:40 +0000

totogo gravatar image

updated 2019-03-28 10:39:41 +0000

Hi there!

Hopefully someone can help me.

In the development builds I can dissect ITS messages to see the message id, which protocol is used (eg. 2 for CAM).

But I cannot see further than that. Higher protocols aren't supported and the data remains a pile of rubbish.

When looking in the source code I would find that there is at least intended support for CAM and DENM.

So my question is: What's the hold up? Why isn't it working yet?

Best regards

PS: I tried several builds on two machines and no configuration could dissect said messages properly.

Edit (27.03.19): I believe I wasn't bringing my point across very well. It's about Wireshark build 3.1.0rc0-190-g41c566b4. The file in question is "epan/dissectors/packet-its.c"

The code reads as if all the dissectors were implemented. Though I can only recognize the lowest level of those ITS messages when running said build. Since I am new to dissector development I have no clue as to why it isn't working.

My idea was to implement them myself using an ASN.1 compiler for wireshark (which name I forgot). When I noticed that there already were all the necessary ASN.1 definitions present. A look in the code surprised me with lots of DENM and CAM (between other) references. Though they wouldn't appear in the build.

Does anybody know what's wrong with the code? Is there an issue tracker where I could follow certain dissectors?


Edit (28.03.19): I thank Anders for clearing things up during the exchange of comments. Though while my original question wasn't answered, I'm satisfied with the result. Therefore I close this question.

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Closed for the following reason the question is answered, right answer was accepted by totogo
close date 2019-03-28 10:40:34.974588


What's an "ITS message"?

Guy Harris gravatar imageGuy Harris ( 2019-02-28 18:11:04 +0000 )edit

(ITS) Intelligent Transport Systems It's all about vehicular communications.

totogo gravatar imagetotogo ( 2019-03-27 13:20:22 +0000 )edit

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answered 2019-03-01 07:40:00 +0000

Jaap gravatar image

So my question is: What's the hold up? Why isn't it working yet?

The short answer to that is: You haven't written the dissector code yet. As this is a community project volunteers provide code, which the core developers will try to integrate.

PS: It could be anyone writing this code, it seems no-one has invested their (spare) time yet.

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It looks like it might be "Intelligent Transport Systems (ITS); Vehicular Communications" (packet-geonw.c)

You coud raise a bug report attaching a trace and reference the apropriate standards so someone can take a look.

Anders gravatar imageAnders ( 2019-03-01 11:32:14 +0000 )edit

So this is either a bug, or it is about to be integrated. Did I understand that correctly?

I was thinking about just waiting a bit and check whether or not it works in newer builds.

totogo gravatar imagetotogo ( 2019-03-27 13:23:23 +0000 )edit

Somewhat confusingly, the Wireshark Bugzilla is also used for enhancement requests, i.e. to add further dissection functions.

There is no "plan" of what's about to be added, the nearest equivalent is checking for pending changes undergoing review on the Wireshark Gerrit review site.

grahamb gravatar imagegrahamb ( 2019-03-27 13:40:46 +0000 )edit

It seems like some ITS stuff IS supported and some got fixed in so you would have to let us know what you think is not working.

Anders gravatar imageAnders ( 2019-03-27 14:09:21 +0000 )edit

Hey, that's great news! So I built version 3.1.0rc0-393-g303ccbe4. But what I found was that there is a new sub tree saying there was "No subdissector found for this Message id/protocol version combination" when looking at a CAM message.

totogo gravatar imagetotogo ( 2019-03-27 14:26:18 +0000 )edit

So what is the Message id/protocol version?

Anders gravatar imageAnders ( 2019-03-27 14:59:45 +0000 )edit

Here it is:

    protocolVersion: 1
    messageID: cam (2)
totogo gravatar imagetotogo ( 2019-03-27 15:04:05 +0000 )edit

Currently only version 2 is supported.

Anders gravatar imageAnders ( 2019-03-27 15:10:06 +0000 )edit

What a bummer. Gotta recheck those ASN.1 files I have. The ones in use didn't differ from the source last time I checked.

totogo gravatar imagetotogo ( 2019-03-27 15:23:06 +0000 )edit

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Asked: 2019-02-28 16:56:40 +0000

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Last updated: Mar 28 '19