[BRIDGE]: set features based on enslaved devices

Make features of the bridge pseudo-device be a subset of the underlying
devices.  Motivated by Xen and others who use bridging to do failover.

Signed-off-by: Catalin BOIE <catab at umrella.ro>
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 40 insertions, 8 deletions

diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
index d9b72fde433c..f564ee99782d 100644
--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c
@@ -21,10 +21,7 @@
 
 static struct net_device_stats *br_dev_get_stats(struct net_device *dev)
 {
-        struct net_bridge *br;
-
-        br = dev->priv;
-
+        struct net_bridge *br = netdev_priv(dev);
         return &br->statistics;
 }
 
@@ -54,9 +51,11 @@ int br_dev_xmit(struct sk_buff *skb, struct net_device *dev)
 
 static int br_dev_open(struct net_device *dev)
 {
-        netif_start_queue(dev);
+        struct net_bridge *br = netdev_priv(dev);
 
-        br_stp_enable_bridge(dev->priv);
+        br_features_recompute(br);
+        netif_start_queue(dev);
+        br_stp_enable_bridge(br);
 
         return 0;
 }
@@ -67,7 +66,7 @@ static void br_dev_set_multicast_list(struct net_device *dev)
 
 static int br_dev_stop(struct net_device *dev)
 {
-        br_stp_disable_bridge(dev->priv);
+        br_stp_disable_bridge(netdev_priv(dev));
 
         netif_stop_queue(dev);
 
@@ -76,7 +75,7 @@ static int br_dev_stop(struct net_device *dev)
 
 static int br_change_mtu(struct net_device *dev, int new_mtu)
 {
-        if ((new_mtu < 68) || new_mtu > br_min_mtu(dev->priv))
+        if (new_mtu < 68 || new_mtu > br_min_mtu(netdev_priv(dev)))
                 return -EINVAL;
 
         dev->mtu = new_mtu;
diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c
index 69872bf3b87e..91bb895375f4 100644
--- a/net/bridge/br_if.c
+++ b/net/bridge/br_if.c
@@ -314,6 +314,28 @@ int br_min_mtu(const struct net_bridge *br)
         return mtu;
 }
 
+/*
+ * Recomputes features using slave's features
+ */
+void br_features_recompute(struct net_bridge *br)
+{
+        struct net_bridge_port *p;
+        unsigned long features, checksum;
+
+        features = NETIF_F_SG | NETIF_F_FRAGLIST 
+                | NETIF_F_HIGHDMA | NETIF_F_TSO;
+        checksum = NETIF_F_IP_CSUM;     /* least commmon subset */
+
+        list_for_each_entry(p, &br->port_list, list) {
+                if (!(p->dev->features 
+                      & (NETIF_F_IP_CSUM|NETIF_F_NO_CSUM|NETIF_F_HW_CSUM)))
+                        checksum = 0;
+                features &= p->dev->features;
+        }
+
+        br->dev->features = features | checksum | NETIF_F_LLTX;
+}
+
 /* called with RTNL */
 int br_add_if(struct net_bridge *br, struct net_device *dev)
 {
@@ -368,6 +390,7 @@ int br_del_if(struct net_bridge *br, struct net_device *dev)
 
         spin_lock_bh(&br->lock);
         br_stp_recalculate_bridge_id(br);
+        br_features_recompute(br);
         spin_unlock_bh(&br->lock);
 
         return 0;
diff --git a/net/bridge/br_notify.c b/net/bridge/br_notify.c
index f8fb49e34764..917311c6828b 100644
--- a/net/bridge/br_notify.c
+++ b/net/bridge/br_notify.c
@@ -65,6 +65,15 @@ static int br_device_event(struct notifier_block *unused, unsigned long event, v
                 }
                 break;
 
+        case NETDEV_FEAT_CHANGE:
+                if (br->dev->flags & IFF_UP) 
+                        br_features_recompute(br);
+
+                /* could do recursive feature change notification
+                 * but who would care?? 
+                 */
+                break;
+
         case NETDEV_DOWN:
                 if (br->dev->flags & IFF_UP)
                         br_stp_disable_port(p);
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 54d63f1372a0..bdf95a74d8cd 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -174,6 +174,7 @@ extern int br_add_if(struct net_bridge *br,
 extern int br_del_if(struct net_bridge *br,
               struct net_device *dev);
 extern int br_min_mtu(const struct net_bridge *br);
+extern void br_features_recompute(struct net_bridge *br);
 
 /* br_input.c */
 extern int br_handle_frame_finish(struct sk_buff *skb);