target/linux/generic/patches-3.18/051-01-bridge-fix-parsing-of-MLDv2-reports.patch

   1 From 1430a5975e1a5f249875faab7fd35b915a8d2397 Mon Sep 17 00:00:00 2001
   2 From: Thadeu Lima de Souza Cascardo <cascardo@redhat.com>
   3 Date: Fri, 22 May 2015 12:18:59 -0300
   4 Subject: [PATCH] bridge: fix parsing of MLDv2 reports
   5
   6 When more than a multicast address is present in a MLDv2 report, all but
   7 the first address is ignored, because the code breaks out of the loop if
   8 there has not been an error adding that address.
   9
  10 This has caused failures when two guests connected through the bridge
  11 tried to communicate using IPv6. Neighbor discoveries would not be
  12 transmitted to the other guest when both used a link-local address and a
  13 static address.
  14
  15 This only happens when there is a MLDv2 querier in the network.
  16
  17 The fix will only break out of the loop when there is a failure adding a
  18 multicast address.
  19
  20 The mdb before the patch:
  21
  22 dev ovirtmgmt port vnet0 grp ff02::1:ff7d:6603 temp
  23 dev ovirtmgmt port vnet1 grp ff02::1:ff7d:6604 temp
  24 dev ovirtmgmt port bond0.86 grp ff02::2 temp
  25
  26 After the patch:
  27
  28 dev ovirtmgmt port vnet0 grp ff02::1:ff7d:6603 temp
  29 dev ovirtmgmt port vnet1 grp ff02::1:ff7d:6604 temp
  30 dev ovirtmgmt port bond0.86 grp ff02::fb temp
  31 dev ovirtmgmt port bond0.86 grp ff02::2 temp
  32 dev ovirtmgmt port bond0.86 grp ff02::d temp
  33 dev ovirtmgmt port vnet0 grp ff02::1:ff00:76 temp
  34 dev ovirtmgmt port bond0.86 grp ff02::16 temp
  35 dev ovirtmgmt port vnet1 grp ff02::1:ff00:77 temp
  36 dev ovirtmgmt port bond0.86 grp ff02::1:ff00:def temp
  37 dev ovirtmgmt port bond0.86 grp ff02::1:ffa1:40bf temp
  38
  39 Fixes: 08b202b67264 ("bridge br_multicast: IPv6 MLD support.")
  40 Reported-by: Rik Theys <Rik.Theys@esat.kuleuven.be>
  41 Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@redhat.com>
  42 Tested-by: Rik Theys <Rik.Theys@esat.kuleuven.be>
  43 Signed-off-by: David S. Miller <davem@davemloft.net>
  44 ---
  45  net/bridge/br_multicast.c |    2 +-
  46  1 file changed, 1 insertion(+), 1 deletion(-)
  47
  48 --- a/net/bridge/br_multicast.c
  49 +++ b/net/bridge/br_multicast.c
  50 @@ -1071,7 +1071,7 @@ static int br_ip6_multicast_mld2_report(
  51
  52                 err = br_ip6_multicast_add_group(br, port, &grec->grec_mca,
  53                                                  vid);
  54 -               if (!err)
  55 +               if (err)
  56                         break;
  57         }
  58