uefi dhcpd.conf stuff

class "UEFI-64-1" {
    match if substring(option vendor-class-identifier, 0, 20) = "PXEClient:Arch:00007";
    if exists user-class and option user-class = "iPXE" {
        filename "default.ipxe";
    } else {
        filename "bin-x86_64-efi/snponly.efi";
    }
}