[syslinux] Support DHCP sname field in PXELINUX

[H. Peter Anvin]

Chris Adams wrote:
> Once upon a time, H. Peter Anvin <hpa at zytor.com> said:
>> I mean, the right thing to do is probably, in order:
>>
>> 1. Use siaddr
>> 2. Use sname
>> 3. Use option 54.
> 
> I've done some more digging, and it appears that the PXE BIOS in the
> computers I'm testing with do not look at the sname field.  They do look
> at option 54 ("server-identifier" in Juniper JUNOS).  It would probably
> be more "correct" then to duplicate that and use (siaddr, option 54) and
> ignore sname (since that is what it looks like the PXE BIOS does).
> 

Right, if we can't get the PXE stack to boot in the first place using 
sname, then we should just ignore it.

OK, option 54 as a fallback it is.

	-hpa