RFC: convert net.inet6.ip6.{accept_rtadv, auto_linklocal} to per-interface flags

[Rui Paulo]

On 26 Jun 2009, at 09:00, Hiroki Sato wrote:

> Hi all,
>
> I want to convert net.inet6.ip6.{accept_rtadv,auto_linklocal} to
> per-interface flags to nuke rc.d/auto_linklocal.  The motivations and
> changes are as follow.  If you are using IPv6 and/or familiar with
> the IPv6 implementation, please let me know your comments.
>
> The ip6.autolinklocal had been enabled but disabled since 6.2R by
> default because automatic configuration of L3 address is insecure.
> However, it makes IPv6 configuration complex because of no link-local
> address on an interface.  Malformed address configuration can be
> happened easily on a system with $ipv6_enable="NO". for example.  In
> addition, the rc.conf knob does not mean the IPv6 functionality is
> completely disabled.  Using an interface for IPv4-only is difficult.
>
> So, I want to add the following changes:
>
> 1. Use per-interface ND6 flag "ifdisabled" as a flag for if it is
>    IPv6-enabled or not.  Set it by default.

This looks okay, but "ifdisabled" seems to mean "disable the  
interface" instead of the actual meaning: "disable ipv6 neighbor  
discovery / disable ipv6 link local". Bikeshed apart, what about:
# ifconfig fxp0 -nd6  (to disable ND6)
# ifconfig fxp0 nd6 (to enable it)

And ifconfig fxp0 will show "nd6" or "-nd6" depending on wether the  
bit is on or off, respectively.

"accept_rtadvd" could follow the same principles.

What do you think?

--
Rui Paulo