macvlan: Avoid unnecessary multicast cloning

[cascardo/linux.git] / drivers / net / macvlan.c

diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index a71fa59..0c65bd9 100644 (file)
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -49,6 +49,7 @@ struct macvlan_port {
        bool                    passthru;
        int                     count;
        struct hlist_head       vlan_source_hash[MACVLAN_HASH_SIZE];
+       DECLARE_BITMAP(mc_filter, MACVLAN_MC_FILTER_SZ);
 };
 
 struct macvlan_source_entry {
@@ -419,6 +420,8 @@ static rx_handler_result_t macvlan_handle_frame(struct sk_buff **pskb)
 
        port = macvlan_port_get_rcu(skb->dev);
        if (is_multicast_ether_addr(eth->h_dest)) {
+               unsigned int hash;
+
                skb = ip_check_defrag(dev_net(skb->dev), skb, IP_DEFRAG_MACVLAN);
                if (!skb)
                        return RX_HANDLER_CONSUMED;
@@ -436,7 +439,9 @@ static rx_handler_result_t macvlan_handle_frame(struct sk_buff **pskb)
                        goto out;
                }
 
-               macvlan_broadcast_enqueue(port, src, skb);
+               hash = mc_hash(NULL, eth->h_dest);
+               if (test_bit(hash, port->mc_filter))
+                       macvlan_broadcast_enqueue(port, src, skb);
 
                return RX_HANDLER_PASS;
        }
@@ -722,12 +727,12 @@ static void macvlan_change_rx_flags(struct net_device *dev, int change)
        }
 }
 
-static void macvlan_set_mac_lists(struct net_device *dev)
+static void macvlan_compute_filter(unsigned long *mc_filter,
+                                  struct net_device *dev,
+                                  struct macvlan_dev *vlan)
 {
-       struct macvlan_dev *vlan = netdev_priv(dev);
-
        if (dev->flags & (IFF_PROMISC | IFF_ALLMULTI)) {
-               bitmap_fill(vlan->mc_filter, MACVLAN_MC_FILTER_SZ);
+               bitmap_fill(mc_filter, MACVLAN_MC_FILTER_SZ);
        } else {
                struct netdev_hw_addr *ha;
                DECLARE_BITMAP(filter, MACVLAN_MC_FILTER_SZ);
@@ -739,10 +744,33 @@ static void macvlan_set_mac_lists(struct net_device *dev)
 
                __set_bit(mc_hash(vlan, dev->broadcast), filter);
 
-               bitmap_copy(vlan->mc_filter, filter, MACVLAN_MC_FILTER_SZ);
+               bitmap_copy(mc_filter, filter, MACVLAN_MC_FILTER_SZ);
        }
+}
+
+static void macvlan_set_mac_lists(struct net_device *dev)
+{
+       struct macvlan_dev *vlan = netdev_priv(dev);
+
+       macvlan_compute_filter(vlan->mc_filter, dev, vlan);
+
        dev_uc_sync(vlan->lowerdev, dev);
        dev_mc_sync(vlan->lowerdev, dev);
+
+       /* This is slightly inaccurate as we're including the subscription
+        * list of vlan->lowerdev too.
+        *
+        * Bug alert: This only works if everyone has the same broadcast
+        * address as lowerdev.  As soon as someone changes theirs this
+        * will break.
+        *
+        * However, this is already broken as when you change your broadcast
+        * address we don't get called.
+        *
+        * The solution is to maintain a list of broadcast addresses like
+        * we do for uc/mc, if you care.
+        */
+       macvlan_compute_filter(vlan->port->mc_filter, vlan->lowerdev, NULL);
 }
 
 static int macvlan_change_mtu(struct net_device *dev, int new_mtu)