Android (lack of) support for DHCPv6

Wed Jun 10 16:39:24 UTC 2015

On Wed, Jun 10, 2015 at 8:35 AM, Tore Anderson <tore at fud.no> wrote:
> * Lorenzo Colitti
>
>> Tethering is just one example that we know about today.

In android's case I am perpetually bemused by the fact they use
dnsmasq for tethered dhcp, and dnsmasq long ago added support for
doing smarter things with slaac, and dhcpv6. Merely upgrading that
package in the android distro would get everything needed except
dhcp-pd support into android (for which openwrt has got some decent
daemons for).

dnsmasq is not used in android for dns (which is too bad as dnssec
support was also added to it and I hope most of the bugs ironed out,
in the last 3 years), as their dns resolver is in java and is
admittedly mildly more secure if less featureful.

I am told that well over 50% of all android development comes from
volunteer developers so rather than kvetching about this it seems
plausible for an outside effort to get the needed features for
tethering and using dhcpv6-pd into it. If someone wanted to do the
work.

>> Another example is
>> 464xlat.
>
> You can't do 464XLAT without the network operator's help anyway (unless
> you/Google is planning on hosting a public NAT64 service?). If the
> network operator actively wants 464XLAT to be used, by providing
> DNS64/NAT64 service, then it seems fairly reasonable to assume that
> they're not going to deploy an IPv6/DHCPv6-only network that limits the
> number of IA_NA per attached node to 1.
>
>> And that's not counting future applications that can take
>> advantage of multiple IP addresses that we haven't thought of yet, and that
>> we will have if we get stuck with
>> there-are-more-IPv6-addresses-in-this-subnet-than-grains-of-sand-but-you-only-get-one-because-that's-how-we-did-it-in-IPv4
>> networks.
>
> Of course. Hard to argue against imaginary things. :-)
>
> On the other hand, there exist applications *today* that do require
> DHCPv6. One such example would be MAP, which IMHO is superior to
> 464XLAT both for the network operator (statlessness ftw) as well as for
> the end user (unsolicited inbound packets work, no NAT traversal
> required). MAP is provisioned with DHCPv6 (I-D.ietf-softwire-map-dhcp),
> so without DHCPv6 support in Android, MAP support in Android is a
> non-starter.
>
> Tore

-- 
Dave Täht
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