[062/146] igmp: call ip_mc_clear_src() only when we have no users of ip_mc_list

Greg KH
2011-06-01T09:20:51Z

From: Veaceslav Falico <vfalico@redhat.com>

[ Upstream commit 24cf3af3fed5edcf90bc2a0ed181e6ce1513d2dc ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
net/ipv4/igmp.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -1172,20 +1172,18 @@ static void igmp_group_dropped(struct ip

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)
@@ -1322,6 +1320,7 @@ void ip_mc_dec_group(struct in_device *i
*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);
@@ -1431,7 +1430,8 @@ void ip_mc_destroy_dev(struct in_device
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);
}
}