recent RTADV changes

[mlelstv%serpens.de@localhost (Michael van Elst)]

Recently the handling of IPv6 router advertisements was changed
so that you can enable/disable this for each interface individually.

According to ndp(8):
     accept_rtadv
             Specify whether or not to accept Router Advertisement
             messages received on the interface.  Note that the kernel
             does not accept Router Advertisement messages unless the
             net.inet6.ip6.accept_rtadv variable is non-0, even if the
             flag is on.  This flag is set to 1 by default.

Unfortunately it is not set to 1 by default, but the global
setting from net.inet6.ip6.accept_rtadv is copied when an
interface is attached. The sysctl variable however is configured
only in rc.d/network for ip6mode=autohost.

As a result a network using router advertisements is broken by default
as the interfaces are attached before rc.d/network is running.

There are two solutions to restore the previous behaviour for autohosts.

- teach rc.d/network to also set the private setting of each
  attached interface for an autohost. It is unclear what should
  happen with the flags for non-autohosts.

- unconditionally enable the accept_rtadv flag for each interface
  (as documented). People needing fine grain control now have to
  _disable_ the flag for interfaces that shouldn't do autoconfiguration.


Suggestions?


Greetings,
-- 
                                Michael van Elst
Internet: mlelstv%serpens.de@localhost
                                "A potential Snark may lurk in every tree."
-- 
-- 
                                Michael van Elst
Internet: mlelstv%serpens.de@localhost
                                "A potential Snark may lurk in every tree."