[Guy Harris <guy@xxxxxxxxxxxx>]

On Jan 26, 2004, at 3:51 PM, Chris Wilson wrote:

> You'd want to be able to pass to the dissector, along with the tvb:
>
> - Whether or not there is a UDH present
> - The GSM DCS value (or at least whether the body is 7bit, 8bit or 
> UCS2)
> - Whether 7bit infomation is packet into bytes (as in the GSM SMS 
> TPDU) or with every 8th bit zero (as in an SMPP PDU).
>
> Any thoughts how this information could be passed?

Define a structure in "packet-gsm_sms-ud.h" that contains all that 
information, and, in all dissectors that call the GSM SMS UD dissector:

	have a local variable that's a structure of that sort;

	before calling the SMS UD dissector, fill in that structure and set 
"pinfo->private_data" to point to it;

and have the SMS UD dissector treat "pinfo->private_data" as a pointer 
to such a structure.