[Dnsmasq-discuss] DHCPv6 ULA & Global address allocation & Apple devices

[Simon Kelley]

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On 21/11/16 15:52, Kevin Darbyshire-Bryant wrote:
> I've got some packet captures now that have helped answer some of
> the questions.
> 
> 1) The DHCPADVERTISE in the log are included in just one packet.
> 
> 2) The solicits from my ipad and the advertises are identical
> except dnsmasq presents the ULA address first whereas odhcpd
> presents the global address first.  Both ULA & global are included,
> just the order gets swapped.
> 
> 3) The ipad requests the IPv6 address presented first in the
> solicit. So for odhcpd it requests global, whereas for dnsmasq it
> requests ULA.
> 
> 4) dnsmasq replies with and only with the requested address (ULA)
> in this case.   odhcpd replies with both global and ULA addresses.
> 
> 
> A few questions result:
> 
> 1) Should dnsmasq reply with all available dhcpv6 ranges even if
> one specific address only is requested, like odhcpd?

I don't know. What would be the point of having requested addresses if
they weren't used?

> 
> 2) Should dnsmasq re-order its replies in the solicits to present
> global first?

Would that help? I guess you really want both addresses.

> 
> 3) Is Apple wrong?
> 

Quite possibly.

> 
> Help! :-)

Do you have packet dumps available? I'm interested if the request has
two IA_NA options, or one IA_NA with two addresses.


Cheers,

Simon.

> 
> 
> Kevin
> 
> 
> PS: As a total hack, I got dnsmasq to ignore any requested
> addresses. Dnsmasq replies with both ULA & Global addresses in the
> reply...and my iPad is happy...it takes the global address.
> 
> 
> 
> 
> --- a/src/rfc3315.c +++ b/src/rfc3315.c @@ -867,13 +867,10 @@
> static int dhcp6_no_relay(struct state * if (!check_ia(state, opt,
> &ia_end, &ia_option)) continue;
> 
> -            if (!ia_option) -              { /* If we get a
> request with a IA_*A without addresses, treat it exactly like a
> SOLICT with rapid commit set. */ save_counter(start); goto
> request_no_address; -              }
> 
> o = build_ia(state, &t1cntr);
> 
> 
> 
> 
> _______________________________________________ Dnsmasq-discuss
> mailing list Dnsmasq-discuss at lists.thekelleys.org.uk 
> http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
> 
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