Date: Thu, 2 Sep 2010 14:28:46 +0000 (UTC) From: "Bjoern A. Zeeb" <bzeeb-lists@lists.zabbadoz.net> To: Frank Razenberg <frank@zzattack.org> Cc: FreeBSD virtualization mailing list <freebsd-virtualization@freebsd.org> Subject: Re: duplicate epair ipv6 addresses Message-ID: <20100902142102.R31898@maildrop.int.zabbadoz.net> In-Reply-To: <4C7FB15D.8040906@zzattack.org> References: <4C7E8E7C.7090708@zzattack.org> <AANLkTikasp%2B6nFuCrDnAy7Vt4-7Lgbyza7AexQ_MCVyH@mail.gmail.com> <4C7F8551.6020901@zzattack.org> <AANLkTinX1G0ncjXrqhs4L6suJJXsywGQ2KS0q9auYxKD@mail.gmail.com> <4C7FA623.2010802@zzattack.org> <20100902134953.C31898@maildrop.int.zabbadoz.net> <4C7FB15D.8040906@zzattack.org>
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On Thu, 2 Sep 2010, Frank Razenberg wrote:
Hey Frank,
> I do have an openvpn setup which also creates a bridge. At one point in time
> it conflicted with the bridge0 interface used for the jails. The openvpn 'up'
> script did the following:
>
> #!/bin/sh
> /sbin/ifconfig bridge0 create
> /sbin/ifconfig bridge0 addm nfe0 addm $dev up
> /sbin/ifconfig $dev up
>
> It may have executed a couple of times while bridge0 already existed and had
> the epairs as members. I don't recall the epair's 'a'-end having different
> ethernet addresses before, but I haven't specifically looked at them. I don't
> believe I do any manual collision detection.
Ok, then this is strange than unless if_bridge(4) is doing it. No,
doesn't seem so and I wouldn't have expected it either:
lion3# ifconfig epair99 create
epair99a
lion3# ifconfig epair99a
epair99a: flags=8842<BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
ether 02:00:00:00:09:0a
lion3# ifconfig epair99b
epair99b: flags=8842<BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
ether 02:00:00:00:0a:0b
lion3# ifconfig bridge0 create
lion3# ifconfig bridge0 up
lion3# ifconfig bridge0 addm epair99a
lion3# ifconfig epair99a
epair99a: flags=8942<BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> metric 0 mtu 1500
ether 02:00:00:00:09:0a
lion3# ifconfig epair99a up
lion3# ifconfig epair99b up
lion3# ifconfig epair99a
epair99a: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> metric 0 mtu 1500
ether 02:00:00:00:09:0a
lion3# ifconfig bridge0
bridge0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
ether be:de:50:ce:29:3b
id 00:00:00:00:00:00 priority 32768 hellotime 2 fwddelay 15
maxage 20 holdcnt 6 proto rstp maxaddr 100 timeout 1200
root id 00:00:00:00:00:00 priority 32768 ifcost 0 port 0
member: epair99a flags=143<LEARNING,DISCOVER,AUTOEDGE,AUTOPTP>
ifmaxaddr 0 port 9 priority 128 path cost 2000
lion3# ifconfig bridge0 addm ix1
lion3# ifconfig epair99a
epair99a: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> metric 0 mtu 1500
ether 02:00:00:00:09:0a
lion3# ifconfig bridge0
bridge0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
ether be:de:50:ce:29:3b
id 00:00:00:00:00:00 priority 32768 hellotime 2 fwddelay 15
maxage 20 holdcnt 6 proto rstp maxaddr 100 timeout 1200
root id 00:00:00:00:00:00 priority 32768 ifcost 0 port 0
member: ix1 flags=143<LEARNING,DISCOVER,AUTOEDGE,AUTOPTP>
ifmaxaddr 0 port 6 priority 128 path cost 20000
member: epair99a flags=143<LEARNING,DISCOVER,AUTOEDGE,AUTOPTP>
ifmaxaddr 0 port 9 priority 128 path cost 2000
As you can see the epair99a interface still has the same ether address
02:00:00:<if:index>:0a as when intiially created.
There is either some memory corruption or other magic happening for you.
> I'm not sure whether this answers your questions, if you need any more info
> please let me know.
Are you having multiple machines with epairs bridge to the same LAN?
If so you may have collisions of epair<N>b nodes with overlapping ether
addresses, which IPv6 ND6 DAD (duplicate address detection) would
notice. You would probably find multiple 02:00:00:00:07:0b addresses
on different machines. Which also means that you'll have to do manual
ether address assignments (see 3rd paragraph of the DESCRIPTION
section in the epair(4) manual page.
/bz
--
Bjoern A. Zeeb Welcome a new stage of life.
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