macvlan: add multicast filter
Setting up IPv6 addresses on configurations with many macvlans
is not really working, as many multicast messages are dropped.
Add a multicast filter to macvlan to reduce the amount of cloned
skbs and overhead.
Successfully tested with 1024 macvlans on one ethernet device.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Ben Greear <greearb@candelatech.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index 7b44ebd7..f494da8 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -29,6 +29,7 @@
#include <linux/if_vlan.h>
#include <linux/if_link.h>
#include <linux/if_macvlan.h>
+#include <linux/hash.h>
#include <net/rtnetlink.h>
#include <net/xfrm.h>
@@ -126,6 +127,13 @@
return vlan->receive(skb);
}
+static unsigned int mc_hash(const unsigned char *addr)
+{
+ u32 val = __get_unaligned_cpu32(addr + 2);
+
+ return hash_32(val, MACVLAN_MC_FILTER_BITS);
+}
+
static void macvlan_broadcast(struct sk_buff *skb,
const struct macvlan_port *port,
struct net_device *src,
@@ -137,6 +145,7 @@
struct sk_buff *nskb;
unsigned int i;
int err;
+ unsigned int hash = mc_hash(eth->h_dest);
if (skb->protocol == htons(ETH_P_PAUSE))
return;
@@ -146,6 +155,8 @@
if (vlan->dev == src || !(vlan->mode & mode))
continue;
+ if (!test_bit(hash, vlan->mc_filter))
+ continue;
nskb = skb_clone(skb, GFP_ATOMIC);
err = macvlan_broadcast_one(nskb, vlan, eth,
mode == MACVLAN_MODE_BRIDGE);
@@ -405,6 +416,18 @@
{
struct macvlan_dev *vlan = netdev_priv(dev);
+ if (dev->flags & (IFF_PROMISC | IFF_ALLMULTI)) {
+ bitmap_fill(vlan->mc_filter, MACVLAN_MC_FILTER_SZ);
+ } else {
+ struct netdev_hw_addr *ha;
+ DECLARE_BITMAP(filter, MACVLAN_MC_FILTER_SZ);
+
+ bitmap_zero(filter, MACVLAN_MC_FILTER_SZ);
+ netdev_for_each_mc_addr(ha, dev) {
+ __set_bit(mc_hash(ha->addr), filter);
+ }
+ bitmap_copy(vlan->mc_filter, filter, MACVLAN_MC_FILTER_SZ);
+ }
dev_uc_sync(vlan->lowerdev, dev);
dev_mc_sync(vlan->lowerdev, dev);
}