[syslinux] blocksize and tsize at TFTP transfer

[Geert Stappers]

Op 20090601 om 10:14 schreef Philippe Auphelle:
> Geert,

Hello Syslinux people,


> > Looking forward to the test results.
> 
> There you are.
> The short story is that in both cases, our TFTP server accepted the
> negotiation to 1408 bytes.
> But the dialog didn't go much further, because in both cases, pxelinux
> then closed the deal just after the OACK by sending back an ERROR
> packet with error code 8 ("Option negotiation failed"), with the error
> message set to "tsize option required".

Which is the only 'option negatiation error message',
it is also printed on non tsize option errors.

> You'll get tsize.zip with both captures at the following URL:
> http://dl.free.fr/rOe6y3WvQ
> 
> So this confirm what I mentioned before about that our PXE/TFTP server:
> 1) the only option it support is blksize,
> 2) it is only able to negotiate blksize when blksize is the first
> option in the options field, and if there are more options, it simply
> ignores them.

My observation of the very same PXE/TFTP server:

* blksize option is (malformed) acknowledged with an extra null
* that only happends when blksize is the _first_ TFTP option
* when tsize is the first TFTP option, there is no OACK,
  but first the TFTP  DATA packet to start the transfer.


I think pxelinux.0 can be modified to cope with that TFTP server,
but right now I would try  gpxelinux.0


Cheers
Geert Stappers