vlan with ipv6 DAD problem

[Marcelo Gondim]

Hi all,

When I add an IPv6 manually on an interface vlan, I get a message 
duplicated IP.

# ifconfig vlan2 inet6 2804:1054:0:2::1/64

dmesg message:
==============
lagg1: IPv6 addresses on em2 have been removed before adding it as a 
member to prevent IPv6 address scope violation.
lagg1: IPv6 addresses on em3 have been removed before adding it as a 
member to prevent IPv6 address scope violation.
vlan2: DAD detected duplicate IPv6 address 2804:1054:0:2::1: NS 
in/out=1/1, NA in=0
vlan2: DAD complete for 2804:1054:0:2::1 - duplicate found
vlan2: manual intervention required

It isn't duplicated IP.

For it to work I have 2 options:

First:

reboot system. With reboot all work.

Second:

# ipfw add 1 deny icmp6 from any to any
# ifconfig vlan2 inet6 2804:1054:0:2::1/64
# ipfw delete 1

That way it works normally.

This may be a bug or am I doing something wrong?

FreeBSD rt01.XXXXX.com.br 9.2-RELEASE FreeBSD 9.2-RELEASE #11 r255918: 
Fri Sep 27 22:09:57 BRT 2013 
root at rt01.XXXXX.com.br:/usr/obj/usr/src/sys/XXXXX  amd64

# ifconfig vlan2
vlan2: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
     options=103<RXCSUM,TXCSUM,TSO4>
     ether 00:15:17:8c:81:d6
     inet 186.xxx.xxx.1 netmask 0xffffffe0 broadcast 186.xxx.xxx.31
     inet6 fe80::215:17ff:fe8c:81d6%vlan2 prefixlen 64 scopeid 0x13
     inet6 2804:1054:0:2::1 prefixlen 64
     nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
     media: Ethernet autoselect
     status: active
     vlan: 2126 parent interface: lagg1

# ping6 -c 5 2804:1054:0:2::2
PING6(56=40+8+8 bytes) 2804:1054:0:2::1 --> 2804:1054:0:2::2
16 bytes from 2804:1054:0:2::2, icmp_seq=0 hlim=64 time=2.050 ms
16 bytes from 2804:1054:0:2::2, icmp_seq=1 hlim=64 time=2.144 ms
16 bytes from 2804:1054:0:2::2, icmp_seq=2 hlim=64 time=2.024 ms
16 bytes from 2804:1054:0:2::2, icmp_seq=3 hlim=64 time=2.157 ms
16 bytes from 2804:1054:0:2::2, icmp_seq=4 hlim=64 time=2.161 ms

--- 2804:1054:0:2::2 ping6 statistics ---
5 packets transmitted, 5 packets received, 0.0% packet loss
round-trip min/avg/max/std-dev = 2.024/2.107/2.161/0.058 ms

cheers,
Gondim