[syslinux] Support DHCP sname field in PXELINUX

[H. Peter Anvin]

Chris Adams wrote:
> I have discovered that the JUNOS DHCP server in Juniper J-series routers
> doesn't support setting the next-server IP address field (I have filed a
> bug report with Juniper and they are working on it).  Instead, it puts
> the "boot server" in the sname field, which PXELINUX currently ignores.
> 
> Here's a simple patch (vs. 3.36) that will take an IP string in the
> field.  My assembly is pretty rusty, and I couldn't quite figure out how
> to use the DNS resolver, so it doesn't handle a hostname.  This does
> work for me with an IP string.

You have no guarantee that sname is an IP string; in fact, in the 
typical case it will not be.

I don't think this patch is safe.

	-hpa