[syslinux] Dialog Menu System ?
H. Peter Anvin
hpa at zytor.com
Tue Nov 14 14:22:34 PST 2006
Darryl Miles wrote:
>
> Would you care to elaborate on "to be necessary to make a modification
> to the TFTP protocol" part ?
>
Yes, what's needed is a new opcode in the TFTP protocol that says "I
heard you, but please wait for the next packet." The reason for that is
that there is no way for the server to distinguish between a resend of
an RRQ due to timeout, and a new request. In order for the tsize option
to work, the "CGI" application needs to finish executing before
transmission begins. If the application is slow, the client might time
out, re-send the RRQ, and spawn another application instance. This
quickly leads to avalanche failure.
This is a fairly trivial extension to the protocol, and can be handled
via the options negotiation mechanism.
> The basic TFTP protocol allows for a GET and PUT file operation. My
> vision of how it might work uses those operations if the file name is
> earmarked at the server as a CGI the server sends data to the executable
> or reads data from the executable. A basic pipe mechanism would do the
> trick, otherwise a run executable using a temporary file.
>
> Simple is good.
In the words of Einstein, make it "as simple as possible, but no simpler."
-hpa
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