[syslinux] pxechn.c32: passing options to iPXE

[Alexandre Blanchette]

On Tue, Jul 16, 2013 at 3:37 PM, Gene Cumm <gene.cumm at gmail.com> wrote:

> On Jul 16, 2013 2:01 PM, "Alexandre Blanchette" <blanalex at gmail.com>
> wrote:
> >
> > On Tue, Jul 16, 2013 at 6:26 AM, Gene Cumm <gene.cumm at gmail.com> wrote:
> >
> > > On Mon, Jul 15, 2013 at 11:57 PM, Alexandre Blanchette
> > > <blanalex at gmail.com> wrote:
> > > > In PXELinux 4.06 (the vanilla version, not gpxelinux.0), I'm trying
> to
> > > use
> > > > pxechn.c32 to call iPXE (undionly) with option 67 set to call an
>  iPXE
> > > > script.
> > > >
> > > > The relevant portion of my PXELinux config looks like this:
> > > >
> > > > LABEL MDT
> > > >   MENU LABEL  ^B - MDT 2012 SP1
> > > >   com32 pxechn.c32
> > > >   APPEND undionly.kpxe -o 67.s=ipxe/mdt.ipxe
> > > >
> > > > However iPXE doesn't seem to get the option correctly, it goes into
> > > > auto-boot mode instead of loading the script.
> > >
> > > Odd.  What's the underlying PXE/UNDI stack?  Could you have gPXE/iPXE
> > > already loaded?
> >
> >
> > No other stack is loaded, only the UNDI driver from the BIOS. I've tried
> it
> > with a VMWare Workstation machine (intel e1000 virtual interface), a
> Lenovo
> > ThinkPad T510 and a Dell Latitude E6530.
>
> Ok.  Is there any scenario for which you'd expect this to work?  Anything
> to test that your expected behavior is observed?  Should using option 67
> work like this?  Would it work with option 209("-c")?  Have you tried
> undionly.kkpxe or undionly.kkkpxe?
>
> Obviously once gPXE/iPXE does its own DHCP, it should use 67 like this.
>
> To get the behavior you desire, you may need a custom undionly.*pxe with a
> custom script to fetch a script based on 67.
>
> --Gene


Oh, I get it now! I thought of option 67 as a command line option for
undionly.kpxe. I was under that impression because I used pxechn.c32 for
wdsnbp.com before, and it jumped immediatly to the cached DHCP response.
We're playing "make believe" with iPXE here, I had to create a small script
to make iPXE jump through the hoops:
#!ipxe
set use-cached 1
autoboot net0

I had to use undionly.kkpxe too, undionly.kpxe wasn't able to read the
cached DHCP response. I also had to use the -W parameter for pxechn.c32.

Thank you!

-- 
Alexandre Blanchette <blanalex at gmail.com>