Ethereal-dev: Re: [Ethereal-dev] New dissector: JPEG File Interchange Format(JFIF)

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From: "Olivier Biot" <ethereal@xxxxxxxxxx>
Date: Tue, 6 Jan 2004 01:23:18 +0100
From: "Gilbert Ramirez"


> On Sat, 2004-01-03 at 21:09, Olivier Biot wrote:
> > Hi all,
> >
> > I just checked in a first version of a JPEG JFIF dissector, and a WSP
patch
> > allowing subdissection of multipart entities (no multipart nesting yet).
> >
>
> So, do you have any plans on adding wiretap support to detect GIF and
> JPEG? You could use Ethereal to open a GIF or JPEG file, wiretap detects
> it,  a new protocol "File" is used, instead of "Frame", to show
> filesystem fields (size, mtime, atime, ctime, filename), and then the
> appropriate dissector is called.

I never thought about this, although I have written GIF and JFIF processing
tools that run from the command-line in the past (2 years ago I think). If I
understand wiretap correctly, I need to register a WTAP_* type for GIF,
another for JFIF etc. I can assign the magic US-ASCII strings "GIF87a" and
"GIF89a" to the WTAP_FILE_IMAGE_GIF, and the sequence { 0xFF, 0xD8, 0xFF,
0xE0, 0x**, 0x**, "JFIF" 0x00 } to the WTAP_FILE_IMAGE_JFIF.

Or do I provide a WTAP_FILE_SUPPORTED_MEDIA where I register all supported
media, and based on the heuristic, hand it over to the appropriate
dissector? How about OS and filesystem robustness (e.g., MacOS used to have
an own file format)?

Any comments are welcome!

Regards,

Olivier