IPv6: "xxx::x already configured" in logs... why?

[Lawrence Stewart]

[resurrecting an old thread]

On 19/06/2014 23:08, Hiroki Sato wrote:
> Larry Rosenman <ler at lerctr.org> wrote
>   in <20140619140801.GA65420 at thebighonker.lerctr.org>:
> 
> le> > le> Ideas? (I may be an idiot, so any criticism welcomed).
> le> > le>
> le> > le> if you need the 1841's config, I can supply that as well.  It's using a Hurricane
> le> > le> electric Tunnel.
> le> >
> le> >  How frequent were the log message added into /var/log/messages?  And
> le> >  when did it start to happen after boot.  Just after lagg0 is
> le> >  configured?
> le> >
> le> > -- Hiroki
> le> Looks like:
> le>
> le> Jun 12 07:00:01 thebighonker kernel: in6_ifadd: 2001:470:1f0f:3ad:223:7dff:fe9e:6e8a is already configured
> 
>  Thank you.  Three more questions:
> 
>  1. output of "ifconfig lagg0", "ifconfig bce0", and "ifconfig bce1".
> 
>  2. output of "netstat -s -i".
> 
>  3. output of "ndp -p".
> 
>  The cause of the message is that the automatically-configured address
>  is not recognized as "configured" one and FreeBSD IPv6 stack is
>  trying to add it every time a Router Advertisement message is
>  received.  I am still not sure why it happened, but the above three
>  would help for further investigation.

I've recently set up a VPS with v6 and am seeing the same "in6_ifadd:
<v6_addr> is already configured" messages in response to periodically
received router advertisements every 5-10 mins. The host is a KVM-based
virtual machine with vtnet-based NIC. v6 is fully functional with the
statically assigned v6 address, but the spam in /var/log/messages is
annoying.


FreeBSD revision:
  FreeBSD lauren 12.0-CURRENT FreeBSD 12.0-CURRENT #0 r315059: Sun Mar
12 20:44:50 AEDT 2017
root at builder-head-amd64:/usr/obj/lauren/usr/src/sys/GENERIC-NODEBUG  amd64


Relevant bits from /etc/rc.conf:
  rtsold_enable="YES"
  ipv6_activate_all_interfaces="YES"
  rtsold_flags="-aF"
  ifconfig_vtnet0_ipv6="inet6 <v6_addr> prefixlen 64"


Interface:
  vtnet0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0
mtu 1500

options=6c07bb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4,TSO6,LRO,VLAN_HWTSO,LINKSTATE,RXCSUM_IPV6,TXCSUM_IPV6>
        ether <mac>
        inet <v4_addr> netmask 0xfffffe00 broadcast <v4_bcast>
        inet6 <v6_linklocal>%vtnet0 prefixlen 64 scopeid 0x1
        inet6 <v6_addr> prefixlen 64
        nd6 options=23<PERFORMNUD,ACCEPT_RTADV,AUTO_LINKLOCAL>
        media: Ethernet 10Gbase-T <full-duplex>
        status: active


I would have thought rtsold should be able to play nice with statically
assigned v6 addresses... any ideas?

Cheers,
Lawrence