Re: Router using non-/64 prefix delegation (ia_pd) needs a normal address (ia_na) to route packets.
Roy Marples
Wed Jul 02 10:47:27 2014
On 02/07/2014 6:08, Robert White wrote:
It _almost_ works....
Comcast, it seems, honors the multiple requests in one packet, but it
replies with one packet per IA, each with the same transaction ID etc.
I believe that the second and subsequent packets with the same xid are
being filtered or ignored. Whichever IA request comes first in the
config file is the one honored so I'm guessing the response packets
are being generated stepwise by the server instead of cumulatively.
It looks like you "clear the status" (and free the data structure)
after a successful reply is parsed. Some sort of keep/more flag in the
ifo->ia[] might be a work around. You'd hang on to the status buffer
and until all ia(s) were satisfied or until it was time to make a new
request. The flag would then also act as a de-dupe for repeated
replies for the same iaid in the same transaction.
A three-packet tcpdump is attached.
Yes, basically we accept the first lease with *some* valid addresses
which we asked for.
So Comcast is essentially enforcing the session (state) per IA which I
don't really want to support as that doesn't easily fit into the design
of dhcpcd.
We can't easily merge it in, because the replies came from different
servers and if they add the unicast option to each session then it just
won't work.
There are also other problems with this.
Maybe it's worth asking them if they plan to support the up and coming
standard?
Here's a link for it again:
https://datatracker.ietf.org/doc/draft-ietf-dhc-dhcpv6-stateful-issues/
I think the easiest solution at this point (if they say no to the above
of course) is add more switches to dhcpcd so you can do this
dhcpcd --noprefixdelegation
dhcpcd --prefixdelegation
It's not pretty, and two daemons is a pretty big hammer, but it would
allow to manage IA in different sessions.
dhcpcd --noprefixdelegation works as dhcpcd currently does, just won't
process any IA_PD options.
dhcpcd --prefixdelegation will only process IA_PD options and will store
state in different files.
Rob "loves a good hole in a standard" White.
Heh
Archive administrator: postmaster@marples.name