Date: Sat, 27 May 2017 14:56:16 +0200 From: Baptiste Daroussin <bapt@FreeBSD.org> To: Andriy Gapon <avg@FreeBSD.org> Cc: Mariusz Zaborski <oshogbo@FreeBSD.org>, Steven Hartland <smh@FreeBSD.org>, "George V. Neville-Neil" <gnn@FreeBSD.org>, Toomas Soome <tsoome@FreeBSD.org>, freebsd-net@FreeBSD.org Subject: Re: svn commit: r314948 - in head: lib/libstand sys/boot/i386/libi386 Message-ID: <20170527125616.3c5h4iag3egvq32s@ivaldir.net> In-Reply-To: <c5f695ad-53f8-b5cd-2b20-d3eeefddf7bb@FreeBSD.org> References: <201703090601.v2961OJx077853@repo.freebsd.org> <c5f695ad-53f8-b5cd-2b20-d3eeefddf7bb@FreeBSD.org>
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--lowxsrzm27t7fc6z Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, May 26, 2017 at 12:27:45PM +0300, Andriy Gapon wrote: > On 09/03/2017 08:01, Mariusz Zaborski wrote: > > Author: oshogbo > > Date: Thu Mar 9 06:01:24 2017 > > New Revision: 314948 > > URL: https://svnweb.freebsd.org/changeset/base/314948 > >=20 > > Log: > > Try to extract the RFC1048 data from PXE. If we get enough info we ca= n skip > > the bootp(). It removes unnecessary DHCP request from pxeloader. > > =20 > > Submitted by: kczekirda > > Sponsored by: Oktawave > > Initiated by: Matthew Dillon > > Reviewed by: smh, gnn, bapt, oshogbo > > MFC after: 3 weeks > > Differential Revision: https://reviews.freebsd.org/D9847 >=20 > Sorry for being late to the party, but this being head hopefully not too = late. >=20 > I am not sure that I agree with the spirit of this change. >=20 > There are network boot setups that do depend on the "unnecessary" DHCP re= quest > from pxeboot. For example, a DHCP server could be configured to return a > different set of parameters depending on a particular PXE client. I pers= onally > use a configuration where the DCHP server sends a boot menu[*] to a PXE c= lient > that's built into network cards. If a FreeBSD boot is selected and pxebo= ot is > started, then the server sends parameters required for the FreeBSD boot > (root-path, etc) in response to the request from pxeboot. > I don't see how I can keep that working after this change. >=20 > Additionally, as far as I can tell, we only get cached > PXENV_PACKET_TYPE_BINL_REPLY. This might cause a problem in environments= where > a separate PXE server (Proxy DHCP) is used. In that case the reply might= not > have the network configuration information which would actually be in > PXENV_PACKET_TYPE_DHCP_ACK. > An example of such a setup is described here: > https://n0dy.com/blog/2014/09/14/network-booting-with-dnsmasq-in-proxy-mo= de/ > Using a separate PXE server is not uncommon in corporate environments too. >=20 > In general, I think that the change was not thought through to cover scen= arios > beyond the basic unattended, FreeBSD-only, single DHCP server network boo= ts. > That scenario is, of course, very common, but it is not the only one. >=20 > At minimum, I would like to have a compile time option to control whether > pxeboot should send a DHCP request of its own or rely entirely on the cac= hed > information. Or maybe pxeboot could be smart enough to do the former if = the > cached reply is missing some required information like the root-path. > Right now, there is no bootp(BOOTP_PXE) under any conditions. >=20 > And my apologies again for missing the original discussion. > My focus was somewhere else at the time. >=20 > [*] It uses PXE_BOOT_MENU and PXE_MENU_PROMPT vendor options for that. >=20 > References: > http://www.pix.net/software/pxeboot/archive/pxespec.pdf I should have been all fixed in head (including some sugar added) Can you confirm? Best regards, Bapt --lowxsrzm27t7fc6z Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEEgOTj3suS2urGXVU3Y4mL3PG3PloFAlkpd18ACgkQY4mL3PG3 PlrooA//QM99YZ3ZzTiRwy8wNkp0sdAVGq/53s+Pj/STIh51kxQjtTWndTRR9UYJ 5V8cGc4GCUnhsgB671qvI8sQfPI5D2aL6G8jXSTukxPvVak4vJeB5a5m17ObrDyO HrZSJc6Ebgkr+7JVkL2U9mdjWb0xoMn0OXBStM+49igSBWW1hcvbC8Vtzs7Jflsm TMEpKLutmRylZzQOSW3khAgYtt3gByfNJbwUifzwwPw9b9ATscxju3zqv0hPf7tC R3gv7ifaK3vDLvlOeGJDUGC9DxosVIzTt1XmQcII+X5deZ9+/hdPQNufG7FR6rhH AQ1OtV8Aqr1thlQeS6mgf5FOuxWNlC4ry9vGte3mk/oW0Tl0Aildnbm006k38UEB AnnSWEYOU7YX5dw+rOODJ/tkfkjIqQVAL1Mn8McSgnlM5MFTFlHubDvvolirmIFI +A7kOD5zAHUOFzLn+n/La87ixW18LCkEQTaXCEO/ZgfNYrxgtDNY+gBbfnnm9Fgi UfdfKLpGQDVK9LCuLLzDolWGgSMCePfL+YZmO7mEraMmaDWrJn+04QJqEyIPfQs0 24Vng0DJi8UVlWCA4VZONeHTX8WenqG2hP7ANJrLoPyvHkr0SqdQSi748m0xPIlJ qVeAu8GmGIzm2AmKOdaSOoUJaSWN3fl5du7kXiRfbyDZK3NcOnY= =al8r -----END PGP SIGNATURE----- --lowxsrzm27t7fc6z--
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