dhcpcd-discuss

On Thu, 21 Nov 2013 08:43:51 +0000
Roy Marples <roy@xxxxxxxxxxxx> wrote:

> It is possible to manage PD in another session from NA but dhcpcd
> wasn't designed for that.
> I don't actually know of a use case where you would actually want it 
> anyway.
> The reason that I say this is that one of the artifacts of using PD 
> means than another interface on the clients network should get a
> working IPv6 address anyway....
> 

Indeed!  I only initially looked at it, since I was a little upset that
my PD inherits the EUI-64 suffix, sharing my MAC with the world.  Then
I moved on to more important problems in my IPv6 setup.

> > 2) When using IA_PD, is it possible to change the address suffix
> > dhcpcd assigns with the PD?  Right now it looks like it uses
> > EUI-64, but I wouldn't mind changing it to ::1.  I'm also unable to
> > get it to use privacy extensions which would also be useful (Does
> > that require RAs or something else I'm missing?).
> 
> Already gotten a ticket for it, just not gotten around to
> implementing it yet.
> http://roy.marples.name/projects/dhcpcd/ticket/297
> 

Cool!  I'll hide behind my poor access to your website as an excuse
for not looking at existing bugs. :)

You did skip over a second, hidden question, though.  Maybe it's a dumb
one, I'm still new to IPv6.  Is it possible to make the interface
receiving the PD still make up temporary addresses for itself?  I'm
still clueless as to what makes that magic happen (is that on
interfaces that come up via SLAAC?).

I also stumbled into another sort of problem.  While fiddling with
dhcpcd at the beginning (figuring out IA_PD, IAIDs, etc), I somehow got
several prefixes delegated to me.  I can only have one at a time, but
restarting dhcpcd will randomly pull a different one from my ISP.  From
a capture, it looks like this happens:

Time Dir Action
0.0000 > Solicit PD
0.1186 < Advertise PD #1
0.1187 > Request PD #1
0.1195 < Advertise PD #2
0.2352 < Reply PD #1

The packets do have the preference option, with different values
(0x80 for PD#1, 0xff for PD#2).  Too bad the request packet was already
in flight, I guess.

I've also seen rebinds where the reply has two IA prefix sections in
the IA_PD option, with PD#2 as the second one with zeroed timers.  Even
after something like that, it still advertises PD#2 to me.

My current solution is to stop touching things and wait for the timers
to expire. Is there an equivalent to "DHCP release" that I can make
dhcpcd do?

Thanks again for the help,
Brian