4 files changed, 137 insertions, 0 deletions

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index c6cb85a85c89..6dc76c1e807b 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -210,12 +210,22 @@ enum state_bit_shift {
 	VIF_STATUS_CONNECTED,
 };
 
+struct xenvif_mcast_addr {
+	struct list_head entry;
+	struct rcu_head rcu;
+	u8 addr[6];
+};
+
+#define XEN_NETBK_MCAST_MAX 64
+
 struct xenvif {
 	/* Unique identifier for this interface. */
 	domid_t          domid;
 	unsigned int     handle;
 
 	u8               fe_dev_addr[6];
+	struct list_head fe_mcast_addr;
+	unsigned int     fe_mcast_count;
 
 	/* Frontend feature information. */
 	int gso_mask;
@@ -224,6 +234,7 @@ struct xenvif {
 	u8 can_sg:1;
 	u8 ip_csum:1;
 	u8 ipv6_csum:1;
+	u8 multicast_control:1;
 
 	/* Is this interface disabled? True when backend discovers
 	 * frontend is rogue.
@@ -341,4 +352,8 @@ void xenvif_skb_zerocopy_prepare(struct xenvif_queue *queue,
 				 struct sk_buff *skb);
 void xenvif_skb_zerocopy_complete(struct xenvif_queue *queue);
 
+/* Multicast control */
+bool xenvif_mcast_match(struct xenvif *vif, const u8 *addr);
+void xenvif_mcast_addr_list_free(struct xenvif *vif);
+
 #endif /* __XEN_NETBACK__COMMON_H__ */
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index 28577a31549d..e7bd63eb2876 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -171,6 +171,13 @@ static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	    !xenvif_schedulable(vif))
 		goto drop;
 
+	if (vif->multicast_control && skb->pkt_type == PACKET_MULTICAST) {
+		struct ethhdr *eth = (struct ethhdr *)skb->data;
+
+		if (!xenvif_mcast_match(vif, eth->h_dest))
+			goto drop;
+	}
+
 	cb = XENVIF_RX_CB(skb);
 	cb->expires = jiffies + vif->drain_timeout;
 
@@ -427,6 +434,7 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
 	vif->num_queues = 0;
 
 	spin_lock_init(&vif->lock);
+	INIT_LIST_HEAD(&vif->fe_mcast_addr);
 
 	dev->netdev_ops	= &xenvif_netdev_ops;
 	dev->hw_features = NETIF_F_SG |
@@ -661,6 +669,8 @@ void xenvif_disconnect(struct xenvif *vif)
 
 		xenvif_unmap_frontend_rings(queue);
 	}
+
+	xenvif_mcast_addr_list_free(vif);
 }
 
 /* Reverse the relevant parts of xenvif_init_queue().
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 3f44b522b831..42569b994ea8 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1157,6 +1157,80 @@ static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size)
 	return false;
 }
 
+/* No locking is required in xenvif_mcast_add/del() as they are
+ * only ever invoked from NAPI poll. An RCU list is used because
+ * xenvif_mcast_match() is called asynchronously, during start_xmit.
+ */
+
+static int xenvif_mcast_add(struct xenvif *vif, const u8 *addr)
+{
+	struct xenvif_mcast_addr *mcast;
+
+	if (vif->fe_mcast_count == XEN_NETBK_MCAST_MAX) {
+		if (net_ratelimit())
+			netdev_err(vif->dev,
+				   "Too many multicast addresses\n");
+		return -ENOSPC;
+	}
+
+	mcast = kzalloc(sizeof(*mcast), GFP_ATOMIC);
+	if (!mcast)
+		return -ENOMEM;
+
+	ether_addr_copy(mcast->addr, addr);
+	list_add_tail_rcu(&mcast->entry, &vif->fe_mcast_addr);
+	vif->fe_mcast_count++;
+
+	return 0;
+}
+
+static void xenvif_mcast_del(struct xenvif *vif, const u8 *addr)
+{
+	struct xenvif_mcast_addr *mcast;
+
+	list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
+		if (ether_addr_equal(addr, mcast->addr)) {
+			--vif->fe_mcast_count;
+			list_del_rcu(&mcast->entry);
+			kfree_rcu(mcast, rcu);
+			break;
+		}
+	}
+}
+
+bool xenvif_mcast_match(struct xenvif *vif, const u8 *addr)
+{
+	struct xenvif_mcast_addr *mcast;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
+		if (ether_addr_equal(addr, mcast->addr)) {
+			rcu_read_unlock();
+			return true;
+		}
+	}
+	rcu_read_unlock();
+
+	return false;
+}
+
+void xenvif_mcast_addr_list_free(struct xenvif *vif)
+{
+	/* No need for locking or RCU here. NAPI poll and TX queue
+	 * are stopped.
+	 */
+	while (!list_empty(&vif->fe_mcast_addr)) {
+		struct xenvif_mcast_addr *mcast;
+
+		mcast = list_first_entry(&vif->fe_mcast_addr,
+					 struct xenvif_mcast_addr,
+					 entry);
+		--vif->fe_mcast_count;
+		list_del(&mcast->entry);
+		kfree(mcast);
+	}
+}
+
 static void xenvif_tx_build_gops(struct xenvif_queue *queue,
 				     int budget,
 				     unsigned *copy_ops,
@@ -1215,6 +1289,31 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
 				break;
 		}
 
+		if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1].type) {
+			struct xen_netif_extra_info *extra;
+
+			extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1];
+			ret = xenvif_mcast_add(queue->vif, extra->u.mcast.addr);
+
+			make_tx_response(queue, &txreq,
+					 (ret == 0) ?
+					 XEN_NETIF_RSP_OKAY :
+					 XEN_NETIF_RSP_ERROR);
+			push_tx_responses(queue);
+			continue;
+		}
+
+		if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1].type) {
+			struct xen_netif_extra_info *extra;
+
+			extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1];
+			xenvif_mcast_del(queue->vif, extra->u.mcast.addr);
+
+			make_tx_response(queue, &txreq, XEN_NETIF_RSP_OKAY);
+			push_tx_responses(queue);
+			continue;
+		}
+
 		ret = xenvif_count_requests(queue, &txreq, txfrags, work_to_do);
 		if (unlikely(ret < 0))
 			break;
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index ec383b0f5443..929a6e7e5ecf 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -327,6 +327,14 @@ static int netback_probe(struct xenbus_device *dev,
 			goto abort_transaction;
 		}
 
+		/* We support multicast-control. */
+		err = xenbus_printf(xbt, dev->nodename,
+				    "feature-multicast-control", "%d", 1);
+		if (err) {
+			message = "writing feature-multicast-control";
+			goto abort_transaction;
+		}
+
 		err = xenbus_transaction_end(xbt, 0);
 	} while (err == -EAGAIN);
 
@@ -1016,6 +1024,11 @@ static int read_xenbus_vif_flags(struct backend_info *be)
 		val = 0;
 	vif->ipv6_csum = !!val;
 
+	if (xenbus_scanf(XBT_NIL, dev->otherend, "request-multicast-control",
+			 "%d", &val) < 0)
+		val = 0;
+	vif->multicast_control = !!val;
+
 	return 0;
 }