[syslinux] PXE Booting EFI

[Gene Cumm]

On Mon, Jan 12, 2015 at 5:41 AM, Patrick Masotta <masottaus at yahoo.com> wrote:
>  >
>  >Excellent investigation and
>  >details.  Thank you for this help.  Given
>  >the details of your situation, I'm
>  >reasonably certain it's a SYSLINUX
>  >bug
>  >but there is still a small chance of it being some sort
>  >of negative interaction.
>  >
> I do not think there's a negative interaction, while the VMware EFI environment correctly retrieves
> the NBP (syslinux.efi), it is the NBP the one that makes mistakes when deciding where the PXE
> server is located. syslinux.efi is taking the next-server IP from an answer from a DHCP server that
> did not identified itself as a PXE server (no option 60). It looks like a bug to me.
>
> I think I "kind" of fixed the bug;
> at syslinux-6.03/efi/pxe.c
>
> void net_parse_dhcp(void)
> {
> ...
>
> //patmod start
>     if(&mode->ProxyOfferReceived)
>         parse_dhcp(&mode->ProxyOffer.Dhcpv4, pkt_len);
>     else
> //patmod end
>
>     parse_dhcp(&mode->PxeReply.Dhcpv4, pkt_len);
>     Print(L"\n");
>
> ...
>
> }
>
> just add the code surrounded by comments
> the idea is to ask if there was a proxyOffer first then parse the corresponding packet.
> a more robust fix probably should include more checking.

EFI has proven to be more robust.  The catch here is order.  The
ProxyOffer data must take precedence over the PxeReply data but both
of them probably need to be parsed.

> I compiled the patch (using Ubuntu 14.04) and now it works !

Excellent.

-- 
-Gene