Wireshark · Ethereal-dev: RE: [Ethereal-dev] Patch to expose OPC/DPC from MTP3, SCCP preferences

["Michael Lum" <mlum@xxxxxxxxxxxxx>]

> -----Original Message-----
> From: Jeff Morriss [mailto:morriss@xxxxxxxxx]
> Sent: Friday, December 05, 2003 9:40 AM
> To: mlum@xxxxxxxxxxxxx
> Cc: ethereal Development List
> Subject: Re: [Ethereal-dev] Patch to expose OPC/DPC from MTP3, SCCP
> preferences
>
>
>
>
> Michael Lum wrote:
>
> > I wanted to make the following changes to the MTP3 dissector:
> >
> > 1.  Add two hidden uint32 fields for 24bit OPC/DPC
> > 	This allows display filtering using the complete 24 bit
> integer value
> > 	as an alternative to something like "mtp3.ansi_opc == 214-170-26".
> >
> > 	i.e.  "mtp3.24bit_opc == 0x66aad6" or "mtp3.24bit_opc == 6728406"
>
> Why not re-use "mtp3.opc" (normally used for ITU) in ANSI--but hidden?
>
One other reason is that currently the opc header field definition use a 14
bit
MASK.

> An alternative to that (that I never had a chance to finish thinking
> about) is to make "mtp3.opc" a string (instead of an integer) and then
> add any values we want:
> 	- decimal
> 	- hex
> 	- 3-8-3 (ITU)
> 	- 8-8-8 (ANSI/China)
>
> The disadvantages (that I have thought of) to doing that (and why I
> added "ansi_opc" instead of doing that at the time) are:
> 	- we'd have to sprintf() any values we want
> 	- it's possible filter expressions that rely on it being a
> number will
> break--but I don't know if anybody ever does "mtp3.opc > 1000" or if
> that's even allowed
> 	- not being an integer means we'd have to actually add
> decimal *and*
> hex (in case some people filter on decimal while others use hex)
>
> The advantages are:
> 	- we could have a pref that chooses which of the formats
> are visible
> (the rest would remain hidden).  Or more than one could be displayed?
> 	- there'd only be one "mtp3.opc" instead of 2 or 3 or...
>