[PATCH][WiP] native DHCPv4 support in net_bootp

[Andrei Borzenkov]

14.10.2015 23:09, Andrei Borzenkov пишет:
> 14.10.2015 21:09, Rivard, Matthew T пишет:
>> Just going by these definitions of bootp and dhcp here:
>> https://technet.microsoft.com/en-us/library/cc781243%28v=ws.10%29.aspx
>>
>> The net_bootp only works with a bootp enabled scope on the dhcp server
>> after chaining from iPXE to grub2.   Without a "bootp" scope setup on
>> the dhcp, calling net_bootp on the adapter fails to get an IP address.
>>
>> So, I guess I could more clearly word that the bootp protocol works
>> when calling net_bootp, but standard dhcp isn't.
>>
> 
> Hmm ... you are right; we are actually doing BOOTP here, not DHCP.
> 

This patch adds support for native DHCPv4 and removes requirement for
BOOTP compatibility support in DHCP server.

This is work in progress, but this works for me in test environment.

Patch changes net_bootp to implement full DHCP transaction. it still
/should/ work with BOOTP pure server (untested, I do not have one). It
also re-implements option processing to support overloaded fields and
consolidates it in one place.

What is currently not implemented

- per interface, per transaction stage retransmit timer. Will be done.

- DHCP server selection. We take first DHCPOFFER or BOOTPREPLY. No plans
to implement.

- DHCP option concatenation (RFC3396). I do not expect to hit it in real
life; could be implemented relatively easy if needed.

- client identifier (RFC6842). I do not expect to hit it in real life;
could be added easily if needed.

grub-dhcp.diff
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