igmp: call ip_mc_clear_src() only when we have no users of ip_mc_list
In igmp_group_dropped() we call ip_mc_clear_src(), which resets the number
of source filters per mulitcast. However, igmp_group_dropped() is also
called on NETDEV_DOWN, NETDEV_PRE_TYPE_CHANGE and NETDEV_UNREGISTER, which
means that the group might get added back on NETDEV_UP, NETDEV_REGISTER and
NETDEV_POST_TYPE_CHANGE respectively, leaving us with broken source
filters.
To fix that, we must clear the source filters only when there are no users
in the ip_mc_list, i.e. in ip_mc_dec_group() and on device destroy.
Acked-by: David L Stevens <dlstevens@us.ibm.com>
Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index 672e476..f1d27f6 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -1155,20 +1155,18 @@
if (!in_dev->dead) {
if (IGMP_V1_SEEN(in_dev))
- goto done;
+ return;
if (IGMP_V2_SEEN(in_dev)) {
if (reporter)
igmp_send_report(in_dev, im, IGMP_HOST_LEAVE_MESSAGE);
- goto done;
+ return;
}
/* IGMPv3 */
igmpv3_add_delrec(in_dev, im);
igmp_ifc_event(in_dev);
}
-done:
#endif
- ip_mc_clear_src(im);
}
static void igmp_group_added(struct ip_mc_list *im)
@@ -1305,6 +1303,7 @@
*ip = i->next_rcu;
in_dev->mc_count--;
igmp_group_dropped(i);
+ ip_mc_clear_src(i);
if (!in_dev->dead)
ip_rt_multicast_event(in_dev);
@@ -1414,7 +1413,8 @@
in_dev->mc_list = i->next_rcu;
in_dev->mc_count--;
- igmp_group_dropped(i);
+ /* We've dropped the groups in ip_mc_down already */
+ ip_mc_clear_src(i);
ip_ma_put(i);
}
}