[openfirmware] TFTP Block Size setting?

[Mitch Bradley]

What exactly is "AIX Open Boot"?  Open Firmware implementations are
usually tied to a specific hardware platform and not to an operating
system.  Over the years, several different Open Firmware
implementations, including the FirmWorks implementation (which is what
James is calling "Open Firmware") and I believe multiple different ones
from various groups in IBM, have been able to boot AIX.

Unless you know which implementation is present, it is hard to say what
optional features that implementation might support.

Some, perhaps most, of the IBM Open Firmware implementations, were
derived from an early version of Apple's Open Firmware.  That early
version was lacking some interactive features, which made it more
difficult to modify than the FirmWorks OFW of the same time period, but
I think that, over time, the IBM implementations got better.

"Out of the box", the FirmWorks Open Firmware only supports the default
TFTP blocksize, but I remember hacking it to support larger blocks for a
specific need.  The details of what I did elude me, but I don't think it
was a difficult change.

On 6/9/2016 10:22 PM, James Cameron wrote:
> Yes, Open Firmware can do HTTP;
> 
>     ok boot http:\\server\path
> 
> but my tests of these are usually DHCP mediated rather than BOOTP and
> three years ago; I don't remember doing it with BOOTP.
> 
> NFS is also possible on Open Firmware;
> 
>     ok boot nfs:\\server\path
> 
> When using HTTP or NFS in Open Firmware change "/" to "\" everywhere
> in a URL, since "/" has a meaning in the device tree parsing.
> 
> And again; no idea about AIX open boot.
> 
> If you can get to the prompt, try it manually, with a prepared file
> offered by HTTP.
> 
> cat >> test << EOF
> \ test
> ." test" cr
> EOF
> 
> cp ... # to http server document root
> 
> ...
> 
>     ok boot http:\\server\path\test
> 
> On Fri, Jun 10, 2016 at 12:41:51AM -0700, Alec wrote:
>> Thank you for sharing this, definitely looks like the blksize isn't variable
>> here.  Next would be to see if AIX open boot supports the http interface for
>> receiving the boot image.
>> I will try modifying the /etc/bootptab to define the tftp filename as a URL and
>> see if that works.  Let me know if at the surface if the below bootp config
>> should cause Open Firmware to retrieve the file over http, if IBM Open Firmware
>> supports http...
>>
>> eg. (using data from [1]here)
>> # modify /etc/bootptab to insert "[2]http://50.21.100.48"
>> aix21.domain.com:bf=[3]http://50.21.100.48/tftpboot/aix21.domain.com:ip=
>> 10.200.50.56:ht=ethernet:sa=50.20.100.48:gw=10.200.50.1:sm=[4]255.255.255.0:
>>
>> Hope that works tomorrow, otherwise time to build out a new NIM service.
>>
>> Alec
>>
>> On Thu, Jun 9, 2016 at 7:37 PM, James Cameron <[5]quozl at laptop.org> wrote:
>>
>>     I don't have the source for AIX open boot, but in Open Firmware the
>>     TFTP implementation is without block size support.
>>
>>     References:
>>
>>     1.
>>     [6]https://code.coreboot.org/p/openfirmware/source/tree/HEAD/ofw/inet/
>>     tftp.fth
>>
>>     2.
>>     [7]https://tools.ietf.org/html/rfc2348 "blksize"
>>
>>     On Thu, Jun 09, 2016 at 06:20:13PM -0700, Alec wrote:
>>     > I am attempting to do an IBM NIM install across a 20ms latency. 
>>     >
>>     > Is there an ability to kick off the network boot on AIX open boot with a
>>     block
>>     > size option for tftp from the ok? Prompt?
>>     >
>>     > Forgive me if this is not an appropriate place for this.
>>     >
>>     > Alec
>>
>>     --
>>     James Cameron
>>     [8]http://quozl.netrek.org/
>>
>> References:
>>
>> [1] http://aix4admins.blogspot.com/2013/07/bootpd-this-is-initial-communication.html
>> [2] http://50.21.100.48/
>> [3] http://50.21.100.48/
>> [4] http://255.255.255.0/
>> [5] mailto:quozl at laptop.org
>> [6] https://code.coreboot.org/p/openfirmware/source/tree/HEAD/ofw/inet/tftp.fth
>> [7] https://tools.ietf.org/html/rfc2348
>> [8] http://quozl.netrek.org/
>