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From: Luigi Rizzo <luigi@labinfo.iet.unipi.it>
Message-Id: <199701201830.TAA14662@labinfo.iet.unipi.it>
Subject: netboot and kernel bootp
To: Tor.Egge@idt.ntnu.no (Tor Egge)
Date: Mon, 20 Jan 1997 19:30:53 +0100 (MET)
Cc: phk@freebsd.org, hackers@freebsd.org
In-Reply-To: <199701031419.PAA21083@pat.idt.unit.no> from "Tor Egge" at Jan 3, 97 03:19:27 pm
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Hi,

I am at a good point in cleaning up the netboot/kernel bootp code
so that booting can be done without using TFTP (I have this already
running). This makes configurations easier since you don't have to
mess up with tftp, and also the netboot code is smaller since it
needs not to implement TFTP. I just need a bit of advice on the
overall design.

First of all, the vendor info in bootp seems to be larger than the 64
bytes currently recognized by our netboot code. Anybody knows the
maximum size ? I have temporarily set it to 256 but maybe even larger
values are allowed (which I would make good use of since some of the
boot info require pathnames, and this would make size limitations less
stringent).

The essential options to netboot/kernel bootp are

    [1] hostname and ip address
    [2] complete root path
    [3] complete swap path
    [4] swapsize (could be determined using nfs...)
    [5] kernel name

plus optionally

    [6] root mount options
    [7] swap mount options

[1] and [5] are no problem as there are bootp tags for the purpose,
namely "ip", "hn" and "bf". For [2], I like the way netboot does
now, i.e "server.ip.address:/root/path" and for this I could use
the "rp" tag. But, since space is tight, one might use the
approach of Tor Egge, and use "sw" as the IP for both root and swap,
and limit "rp" to the path only.

[3,4,6,7] unfortunately do not seem to have predefined tags, so I
should use generic tags TXXX.  I have checked RFC1533 (the last
update to RFC1048 that I know of) and there does not seem to be
any tag for this purpose. So, which tags should I use ?

If no suggestion comes, I'll stick with the following:

	bf="/kernel.name:\
	rp="server.ip.address:/root/filesystem":\
	T128="swap.ip.address:/swap/filesystem":\
	T129=swap_size:\
	T130="root_mount_options":\
	T131="swap_mount_options":

Feedback appreciated.

	Thanks
	Luigi
-----------------------------+--------------------------------------
Luigi Rizzo                  |  Dip. di Ingegneria dell'Informazione
email: luigi@iet.unipi.it    |  Universita' di Pisa
tel: +39-50-568533           |  via Diotisalvi 2, 56126 PISA (Italy)
fax: +39-50-568522           |  http://www.iet.unipi.it/~luigi/
_____________________________|______________________________________