kern/47100: IPv6 temporary addresses are broken (RFC 4941/RFC 3041)

[Taylor R Campbell <campbell+netbsd%mumble.net@localhost>]

>Number:         47100
>Category:       kern
>Synopsis:       IPv6 temporary addresses are broken (RFC 4941/RFC 3041)
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Oct 21 18:55:00 +0000 2012
>Originator:     Taylor R Campbell <campbell+netbsd%mumble.net@localhost>
>Release:        NetBSD 6.99.12
>Organization:
>Environment:
Architecture: amd64
Machine: amd64
>Description:

        We have a sysctl knob net.inet6.ip6.use_tempaddr, which
        controls whether NetBSD will generate IPv6 temporary addresses
        according to RFC 3041 (obsoleted by RFC 4941), but this never
        got wired up to the source address selection code.  Other
        operating systems, such as FreeBSD, have another sysctl knob,
        net.inet6.ip6.prefer_tempaddr, which instructs the kernel to
        prefer temporary addresses for new outgoing connections, but we
        don't have that either.

>How-To-Repeat:

        Set net.inet6.ip6.use_tempaddr=1.  Watch your MAC address get
        broadcast on the IPv6 internet nevertheless.  Grumble.

>Fix:

        Yes, please!