macvlan: receive multicast with local address

When implementing VRRP v2 using macvlan several problems were
discovered.  VRRP is weird in that all routers participating
in a redundant group use the same virtual MAC address.
Macvlan is a natural driver to use for this but it doesn't
work.  The problem is that packets with a macvlan device's
source address are not received.

The problem is actually a regression that date back almost 2 years now.
The original problems started with:

commit 618e1b7482f7a8a4c6c6e8ccbe140e4c331df4e9
Author: Arnd Bergmann <arnd@arndb.de>
Date:   Thu Nov 26 06:07:10 2009 +0000

    macvlan: implement bridge, VEPA and private mode

This patches restores the original 2.6.32 behavior. Allowing multicast
packets received with the VRRP source address to be received.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index a3ce3d4561ed..74134970b709 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -192,6 +192,13 @@ static rx_handler_result_t macvlan_handle_frame(struct sk_buff **pskb)
                          */
                         macvlan_broadcast(skb, port, src->dev,
                                           MACVLAN_MODE_VEPA);
+                else {
+                        /* forward to original port. */
+                        vlan = src;
+                        ret = macvlan_broadcast_one(skb, vlan, eth, 0);
+                        goto out;
+                }
+
                 return RX_HANDLER_PASS;
         }