[syslinux] PXELINUX: DHCP field giaddr (pxe_bootp_t.gip)

[Gene Cumm]

On Mon, Dec 26, 2011 at 07:40, Gene Cumm <gene.cumm at gmail.com> wrote:
> On Fri, Dec 23, 2011 at 08:57, Gene Cumm <gene.cumm at gmail.com> wrote:
>> Right now, I almost have pxechn.c32 in a fully functional state by
>> adding a parameter to allow pure hex input of an option and its data.
>> It allows uppercase and lowercase entry with or without octet
>> delimiters (which must not match [0-9A-Fa-f]) and requires 2-digit
>> entry for the octet.  This is an extremely loose input format such
>> that users may utilize it in their preferred format.
>>
>> After adding this, I believe I have about everything implemented
>> except I'm uncertain about the DHCP field giaddr (pxe_bootp_t.gip).
>> My current test environment doesn't utilize this (just 0).  I'm mostly
>> looking to see if it's something that it might be desirable to modify.
>>  DHCP fields sname and siaddr are already adjusted as needed.
>
> Rereading RFC 2131 and finally finding an old capture, it's the
> subnet-local IP address for the DHCP relay agent.
>
> RFC 3396 allows for the encoding of options that exceed 255 octets or
> otherwise must be split.  I'm assuming that PXELINUX and
> dhcp_unpack_packet()/dhcp_pack_packet() have currently no way to deal
> with this data and that it's likely not planned as there has been no
> use case for it.

Reading over dhcp_unpack_field() and dhcp_pack_field_zero(), they
appears to handle RFC 3396 for long options and split options.

-- 
-Gene