[Babel-users] AHCP and IPv4 support

[Juliusz Chroboczek]

I confirm what Gabriel has said.  AHCP does not need any IPv6 (global)
addresses, but it does need IPv6 support in the kernel.  This is
unlikely to change in the foreseeable future.

> I have checked config file for the kernel and there was "IPv6 not
> set".

Please file a bug against Android.

> why does AHCP require some sort of IPv6 communication?

Contrary to what Gabriel said, there are very good reasons why AHCP
requires IPv6 support in the kernel.

Since AHCP's task is assigning IP addresses, AHCP needs to be able to
communicate before it has assigned IP addresses (duh).  In IPv6 this is
easy -- just use link-local addresses.  In IPv4, it requires some nasty
hacks, such as putting the undefined address in the source address field
of the IPv4 headers; this kind of hacks can only be done by doing some
nasty stuff using raw sockets and building your packets yourself,
definitely not something I'm willing to do just to support the few
platforms that still have no support for IPv6.

                                        Juliusz