busybox udhcp settings/options help

[bch at shroggslodge.freeserve.co.uk]

Thank you for taking the time to reply. Much appreciated.

With respect I have no idea what you are talking about :-)    That is down
to my lack of knowledge obviously.

I thought the 'boot_file' parameter was the place to identify the [boot]
file name that a TFTP server would send, once contacted, in the case of PXE
type network booting.

I was trying to understand what I needed to put in the udhcpd.conf file to
support pxe booting.  That lead me to noticing that there were the two boot
file references: the  'boot_file'  and the 'options bootfile' which I did
not understand why there needed to be two.

Same observation/question goes for the 'sname' and the 'option tftp'.

Your answer does not seem to relate to those observations, so have I
understood it wrong as to what they are [both] there for ?


Regards




On 29 January 2017 at 17:48, Denys Vlasenko <vda.linux at googlemail.com>
wrote:

> On Thu, Jan 26, 2017 at 10:22 PM,  <bch at shroggslodge.freeserve.co.uk>
> wrote:
> > Please can anyone explain what the 'boot_file'  parameter is specifically
> > for  and what udhcp does with it ?
> > Also, what is the difference between that 'boot_file' parameter and then
> the
> > optional 'opt bootfile <filename>' parameter ?
>
> There is a fixed-size 128-byte boot_file field in DHCP packets,
> it is a feature inherited from BOOTP
> (new, DHCP options use variable-sized storage in the packet).
>
> If it is not starting with zero byte, udhcpc (client) exports it
> into $boot_file env var for its script (the -s SCRIPT thing)
> to use in whatever way SCRIPT wants.
>
> udhcpd (server) will fill it with zeroes inlees you specify
>     boot_file FILE
> in udhcpd.conf.
> In the same file,
>     opt bootfile FILE
> sets the value of DHCP option 67, not of the boot_file field.
>
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