Syslinux - Mar 2003 - PXElinux question - not in FAQ

Peter, we have met in Cyber space looong time ago, when I was requesting 
10:minor numbers for the Netwinder project....

Now I am trying to build a network boot for Xandros distribution.

I have it working, however I need to do 2 DHCP cycles - 1 happens in 
PXE, and then it repeats in my network boot code (based on BusyBox). All 
I need in the second stage is the NFS image address, passed by DHCP as
    option root-path "dell:/XandrosInstallCD";

I could modify DHCP to use option vendor-encapsulated-options instead. 
Is this one "eaten" by PXE firmware? What for is it in the first
place?

Would be nice if PXE linux could pass on the kernel command line other 
vars similar to IPAPPEND info, but from your code  it looks that 
pxelinux is not parsing other DHCP options...

Unless I could use your PXELINUX_MAGIC option. Since I do not need extra 
config files, I could use the field to specify NFS root. But how to pass 
it later to the kernel?

Thanks, Woody

Woody Suwalski wrote:
> Peter, we have met in Cyber space looong time ago, when I was requesting 
> 10:minor numbers for the Netwinder project....
> 
> Now I am trying to build a network boot for Xandros distribution.
> 
> I have it working, however I need to do 2 DHCP cycles - 1 happens in 
> PXE, and then it repeats in my network boot code (based on BusyBox). All 
> I need in the second stage is the NFS image address, passed by DHCP as
>    option root-path "dell:/XandrosInstallCD";
> 
> I could modify DHCP to use option vendor-encapsulated-options instead. 
> Is this one "eaten" by PXE firmware? What for is it in the first
place?
> 
> Would be nice if PXE linux could pass on the kernel command line other 
> vars similar to IPAPPEND info, but from your code  it looks that 
> pxelinux is not parsing other DHCP options...
It doesn't, and it might not even get them without asking the DHCP 
server specifically *in the request*.

Once initramfs is supported in the kernel there will probably be a way 
to get the PXE packets in binary form passed to the kernel.  However, 
quite frankly, I think you're actually better off doing exactly what 
you're doing now -- ask DHCP twice.

	-hpa