[Guy Harris <guy@xxxxxxxxxx>]

> The VJ dissector needs to replace the compressed tcp/ip header with the 
> decompressed version of it.  It is nasty to modify the original
> tvbuff;

It's not just nasty, it's completely forbidden.  Tvbuffs are read-only
to all dissectors.

> the 
> path of least resistance is to build a new tvbuff with the decompressed 
> header.  After the header decompression both the compressed and the 
> decompressed tvbuffs are displayed in separate frames.  In the VJ dissector 
> I don't have the bytes preceding the ppp payload which can potentially be 
> 1-2 bytes for the ppp protocol field to many depending on what ppp is 
> running over (pppoe comes to mind).

Why do you *need* those bytes?  Doesn't the decompresser just produce an
IP datagram?