From: Ben Greear <redacted>
Date: Thu, 26 Aug 2010 14:19:30 -0700

In our case, we enable IPv6 in user-space, and then we want to get
some immediate indication that indeed the process is working as
expected.

When DAD completes, you'll get a similar indication.

In other cases, we want to remove all IPv6 addresses, so if we have
not even been notified that the IP exists, then we cannot know how
to delete it.

You can add a netlink message to accomplish that.  This has been
asked for in other contexts as well.

We've been running this patch for several years, and it has not
caused any obvious problems with other tools, so I think it's safe
enough.

And your level of exposure compared to upstream is...? :-)

Anyways, even if it's implemented in an error free way it's still
not necessary the best way to go about this.