[059/165] igmp: call ip_mc_clear_src() only when we have no users of ip_mc_list

[Greg KH]

2.6.39-stable review patch.  If anyone has any objections, please let us know.

------------------
Content-Length: 1911
Lines: 67


From: Veaceslav Falico <vfalico@xxxxxxxxxx>

[ 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@xxxxxxxxxx>
Signed-off-by: Veaceslav Falico <vfalico@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
 net/ipv4/igmp.c |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -1169,20 +1169,18 @@ 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)
@@ -1319,6 +1317,7 @@ 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);
@@ -1428,7 +1427,8 @@ 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);
 	}
 }


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/