RE: [PATCH][WiP] native DHCPv4 support in net_bootp

[Rivard, Matthew T]

Thanks for the patch, finally had an opportunity to apply it and test it.   It 
did require disabling -Werror in order for the diff that was originally 
supplied to compile, as there's a couple of variables that were throwing 
uninitialized warnings.  


-----Original Message-----
From: Andrei Borzenkov [mailto:address@hidden 
Sent: Sunday, January 17, 2016 7:42 AM
To: Rivard, Matthew T <address@hidden>; The development of GNU GRUB 
<address@hidden>
Subject: [PATCH][WiP] native DHCPv4 support in net_bootp

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.asp
>> x
>>
>> 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.