kernel-packages team mailing list archive

[Sarah Newman <srn@xxxxxxxxx>]

Hi,

I am using 12.04 and that particular sequence appears to be expected
behavior due to duplicate address detection in ipv6 leading to the ipv6
address being tentative.  I see similar behavior on an ethernet port
which has never physically been connected to anything.

Before attaching anything to the bridge, it has NO-CARRIER and tentative
ipv6 address, ping does not work:

$ ip addr show br0
26: br0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN 
    link/ether 00:16:3e:ff:00:01 brd ff:ff:ff:ff:ff:ff
    inet6 2605:2700:0:18::1/64 scope global tentative 
       valid_lft forever preferred_lft forever

After attaching something which is itself up:
$ ip addr show br0
26: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP 
    link/ether 00:16:3e:ff:00:01 brd ff:ff:ff:ff:ff:ff
    inet6 2605:2700:0:18::1/64 scope global 
       valid_lft forever preferred_lft forever
    inet6 fe80::216:3eff:feff:1/64 scope link 
       valid_lft forever preferred_lft forever

ping works at this point.

Furthermore, after removing the interface, NO-CARRIER is back but the
address is still no longer tentative and is still pingable:

$ ip addr show br0
26: br0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN 
    link/ether 00:16:3e:ff:00:01 brd ff:ff:ff:ff:ff:ff
    inet6 2605:2700:0:18::1/64 scope global 
       valid_lft forever preferred_lft forever
    inet6 fe80::216:3eff:feff:1/64 scope link 
       valid_lft forever preferred_lft forever
$ ping6 -c1 2605:2700:0:18::1
PING 2605:2700:0:18::1(2605:2700:0:18::1) 56 data bytes
64 bytes from 2605:2700:0:18::1: icmp_seq=1 ttl=64 time=0.047 ms

With 3.5.0-43-generic, I set net.ipv6.conf.all.dad_transmits and
net.ipv6.conf.all.accept_dad to 0 and that doesn't cause the addresses
to no longer be tentative. It seems like redhat may have had a similar
bug https://bugzilla.redhat.com/show_bug.cgi?id=709271 but it is not
clear what they did to fix it.  I have not yet tried more recent kernels
to see if the problem is fixed there.

** Bug watch added: Red Hat Bugzilla #709271
   https://bugzilla.redhat.com/show_bug.cgi?id=709271

-- 
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux in Ubuntu.
https://bugs.launchpad.net/bugs/894272

Title:
  ipv6 broken for bridge

Status in “linux” package in Ubuntu:
  Triaged

Bug description:
  ipv6 seems to be broken on bridges in oneiric:

  root@office:/home/markus# uname -a
  Linux office 3.0.0-12-virtual #20-Ubuntu SMP Fri Oct 7 18:25:20 UTC 2011 i686 i686 i386 GNU/Linux
  root@office:/home/markus# brctl addbr test
  root@office:/home/markus# ip -6 addr add 2001:DB8:4309:2388::2/64 dev test
  root@office:/home/markus# ifconfig test up
  root@office:/home/markus# ifconfig test
  test      Link encap:Ethernet  HWaddr fa:12:c8:34:79:69  
            inet6 addr: 2001:db8:4309:2388::2/64 Scope:Global
            UP BROADCAST MULTICAST  MTU:1500  Metric:1
            RX packets:0 errors:0 dropped:0 overruns:0 frame:0
            TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
            collisions:0 txqueuelen:0 
            RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
  root@office:/home/markus# ping6 2001:DB8:4309:2388::2
  PING 2001:DB8:4309:2388::2(2001:db8:4309:2388::2) 56 data bytes
  ^C
  --- 2001:DB8:4309:2388::2 ping statistics ---
  7 packets transmitted, 0 received, 100% packet loss, time 5999ms

  root@office:/home/markus#

  The address is correctly assigned to the interface, but it can't be
  pinged.

  This used to work in natty:

  root@yavin:/home/markus# uname -a
  Linux yavin 2.6.38-12-virtual #51-Ubuntu SMP Wed Sep 28 17:57:49 UTC 2011 i686 i686 i386 GNU/Linux
  root@yavin:/home/markus# brctl addbr test
  root@yavin:/home/markus# ip -6 addr add 2001:DB8:4309:2388::2/64 dev test
  root@yavin:/home/markus# ifconfig test up
  root@yavin:/home/markus# ifconfig test
  test      Link encap:Ethernet  HWaddr 0a:38:75:60:be:f1  
            inet6 addr: fe80::838:75ff:fe60:bef1/64 Scope:Link
            inet6 addr: 2001:db8:4309:2388::2/64 Scope:Global
            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
            RX packets:0 errors:0 dropped:0 overruns:0 frame:0
            TX packets:17 errors:0 dropped:0 overruns:0 carrier:0
            collisions:0 txqueuelen:0 
            RX bytes:0 (0.0 B)  TX bytes:1446 (1.4 KB)
  root@yavin:/home/markus# ping6 2001:DB8:4309:2388::2
  PING 2001:DB8:4309:2388::2(2001:db8:4309:2388::2) 56 data bytes
  64 bytes from 2001:db8:4309:2388::2: icmp_seq=1 ttl=64 time=0.035 ms
  64 bytes from 2001:db8:4309:2388::2: icmp_seq=2 ttl=64 time=0.034 ms
  64 bytes from 2001:db8:4309:2388::2: icmp_seq=3 ttl=64 time=0.034 ms
  ^C
  --- 2001:DB8:4309:2388::2 ping statistics ---
  3 packets transmitted, 3 received, 0% packet loss, time 1999ms
  rtt min/avg/max/mdev = 0.034/0.034/0.035/0.004 ms

  root@yavin:/home/markus#

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/894272/+subscriptions