Hi

Thanks for the response.

Guy Harris wrote:
> On Feb 6, 2007, at 3:56 PM, Shehjar Tikoo wrote:
> Note: anonymizing packets isn't what a dissector does; a dissector  
> dissects packets.  If you want hooks to do anonymization that  
> understands particular protocols, the way to do that would be to add  
> hooks for anonymization, rather than trying to abuse the protocol  
> dissection mechanism and being then forced into adding more mechanism  
> to all ow that sort of abuse.

Yes, its true that I was trying to abuse the dissector mechanism but 
hooks sound like a cleaner idea.

> So what sort of hooks into the *existing* dissectors do you need in  
> order to do anonymization?

Right now I am basically diverting each RPC message into a function that 
calls tcp_dissect_pdus to ensure my anonymizer gets a desegmented 
message, so in general a per-message hook sounds like what I need.

One issue is, how to handle hooks which need desegmented messages but 
corresponding dissectors which can do without desegmentation. Though I 
can see this being resolved by executing the hook after the dissector 
with desegmentation pref enabled, in the case of RPC. That should ensure 
that the hook gets a desegmented message.

The problem with this, is that the hook will not get called each time a 
dissector gets called, because the dissector has requested 
desegmentation and needs to return(..to the caller from the transport 
layer..), before it can hand over the tvbuff to the hook. I am not sure 
if such a behaviour will be acceptable in wireshark?

I haven't thought much about how these hooks will effect other layers 
and dissectors because I haven't looked into them much.

Thanks again
Shehjar
_______________________________________________
Wireshark-dev mailing list
[email protected]
http://www.wireshark.org/mailman/listinfo/wireshark-dev

Reply via email to