[PATCH 4.12 11/99] net: igmp: Use ingress interface rather than vrf device

Greg Kroah-Hartman
2017-08-28T08:06:15Z

From: David Ahern <dsahern@gmail.com>

[ Upstream commit c7b725be84985532161bcb4fbecd056326998a77 ]

Anuradha reported that statically added groups for interfaces enslaved
to a VRF device were not persisting. The problem is that igmp queries
and reports need to use the data in the in_dev for the real ingress
device rather than the VRF device. Update igmp_rcv accordingly.

Fixes: e58e41596811 ("net: Enable support for VRF with ipv4 multicast")
Reported-by: Anuradha Karuppiah <anuradhak@cumulusnetworks.com>
Signed-off-by: David Ahern <dsahern@gmail.com>
Reviewed-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv4/igmp.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -1007,10 +1007,18 @@ int igmp_rcv(struct sk_buff *skb)
{
/* This basically follows the spec line by line -- see RFC1112 */
struct igmphdr *ih;
- struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
+ struct net_device *dev = skb->dev;
+ struct in_device *in_dev;
int len = skb->len;
bool dropped = true;

+ if (netif_is_l3_master(dev)) {
+ dev = dev_get_by_index_rcu(dev_net(dev), IPCB(skb)->iif);
+ if (!dev)
+ goto drop;
+ }
+
+ in_dev = __in_dev_get_rcu(dev);
if (!in_dev)
goto drop;