[libvirt] dhcp6, radvd, ip6tables, etc. (update)

[Gene Czarcinski]

On 10/31/2012 11:53 AM, Laine Stump wrote:
> That's just a safeguard to enforce the ipv4-only status of dhcp in the
> current libvirt. Just remove that restriction from the function
> virNetworkDefUpdateIP() as a part of your patch adding ipv6 dhcp support.
>
OK, removing the ipv4 test has net-update ipv6 working as well as ipv4 does.

Observation: this is definitely a work-in-progress.  I only tried 
ip-dhcp-range and ip-dhcp-host.  The ip-dhcp-range produced the expected 
in the the xml was updated and dnsmasq was restarted.  With 
ip-dhcp-host, it only did the right thing if the network was down. If it 
was started, nothing much happened.

A suggestion, before F18 goes with 0.10.2, I suggest that the virsh 
man-page be updated.  Currently, you would think that all of the stuff 
worked.  Clearly, it does not.  At best, users will be confused.  I 
suggest listing the functions that are planned but not currently 
implemented.

Speaking of documentation.  This should be updated for DHCPv6:
http://libvirt.org/http://libvirt.org/formatnetwork.html and there is 
docs/http://libvirt.org/formatnetwork.html.in in the git. However, it is 
not clear what the process is for changing/updating the documentation.  
Doing a grep on the log does not show a lot of commits being performed 
on it.

While a lot of using IPv6/DHCP6 is straight-forward, there are a couple 
of twists such as not specifying a MAC address for a v6 dhcp-host 
specification.

One other thing.  I am thinking about a separate patch which will 
replace radvd with dnsmasq doing the work.  I first need to look into 
dsnamsq a bit more to understand if and how it could do the job.  Given 
it could, a small change for dnsmasq would eliminate the need for radvd.

I know there is some touchiness about this so I am thinking of adding a 
"special xml keyword" which would switch between radvd and dnsmasq.

BTW, I am assuming this is all post v1.0.0.  I have currently completed 
the dhcp6 patch (net-update was the last  piece) but I need to let 
things work for a while to see if I missed anything.  If anyone wants to 
look at these patches, I can post them to this list or send them 
direct.  However, I want to wait until v1.0.0 gets released before 
submitting them for review, etc.

Gene