Wireshark · Wireshark-dev: Re: [Wireshark-dev] Informing user of incomplete dissection

[Michael Mann <mmann78@xxxxxxxxxxxx>]

DISSECTOR_ASSERT is definitely wrong, that's intended for detecting coding screw ups not for anything the wire generates.

 

You should always put all bytes in some sort of field so that the user has access to them.  Fieldname could be a clue, like my_dissector.undissected_bytes.

 

Expert info is probably the best way to go because it should color some fields of your protocol differently to make the user aware of the incomplete dissection.  There's even a specific expert info type, PI_UNDECODED to note such an occurrence (typically PI_WARN)

 

 

 

-----Original Message-----
From: Mike Morrin <morrinmike@xxxxxxxxx>
To: Developer support list for Wireshark <wireshark-dev@xxxxxxxxxxxxx>
Sent: Fri, Mar 4, 2016 7:55 pm
Subject: [Wireshark-dev] Informing user of incomplete dissection

I have a dissector which does not yet dissect all of the possible information elements of a protocol.

What should the dissector do when it recognises that an IE cannot be handled?

• Ignoring the un-dissected octets leaves the user with a false sense of believing the dissection was complete
• DISSECTOR_ASSERT is much too invasive.
• Expert info, would seem to be the best option, but I recall that it was intended to be used for providing information about the captured packets, rather than about dissector deficiencies.

What is the generally accepted solution?

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