Re: Initializing a device

[Guy Harris <guy () alum mit edu>]

On Jan 6, 2012, at 8:16 AM, Jakub Zawadzki wrote:

> On Fri, Jan 06, 2012 at 04:47:09PM +0100, Akos Vandra wrote:
> > Another reason why this is not a good approach: Let's get wireshark in
> > the picture. Let's say the user selected a canusb device. The only way
> > for wireshark to know what parameters (ex. baudrate) the canusb device
> > needs is if wireshark knows how the canusb device works. This is bad.
> > IMHO one of the main goals of libpcap would be to hide how the capture
> > device actually works from the user application, so that it can use a
> > device-independent way of getting packets.
>
> IMHO user need to know what parameters he can (or need to) set, and
> 1/ He can use either enviroment variables,
> like:
>  CANUSB_BAUDRATE=2400 tcpdump -i canusb0
>  USBRADIO0_CHANNEL=12 tcpdump -i usbradio0
>
> 2/ Capture from interfaces like:
>  tcpdump -i canusb0:baudrate=2400,parity
> or
>  tcpdump -i usbradio0:channel=12
>
> I used something like (2/) in nflog cause there was no other way,
>
> but I agree possibility to add custom parameters would be great, and much
> more user friendly!

Well, maybe.  From a command-line user's perspective, it's the difference between

        CANUSB_BAUDRATE=2400 tcpdump -i canusb0

and

        tcpdump -i canusb0:baudrate=2400

and

        tcpdump -i canusb0 -o baudrate=2400

and

        tcpdump -i canusb0 --baudrate 2400

and so on.  You have a bunch of parameters that have "short names" to use on the command line, types, and values.

> From a GUI perspective, perhaps.  You'd have a dialog box that has, for example, a list of

        name: [value widget]

where the value widget might be a spinbox for numerical parameters, a combo box/option menu/whatever for 
enumerated-data-type parameters, a checkbox for Boolean parameters, and a text entry box for text parameters.  Either 
"name" would be the same as the command-line short name, or it'd be some "descriptive name" - perhaps there'd be a 
tooltip with a descriptive phrase.  That gets more complicated if your GUI app is internationalized; Wireshark isn't, 
and at least one developer whose mother tongue isn't English has argued against it:

        http://wiki.wireshark.org/Development/Translations

but I don't know whether everyone would agree with that, and there are other pcap-based network analyzers:

        http://ksniffer.sourceforge.net/

        http://sourceforge.net/projects/packetyzer/

so I don't want to assume it's tcpdump and Wireshark and nothing else.-
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