8 files changed, 98 insertions, 39 deletions

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 04119b1e7cdb..27c413aa15da 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1480,20 +1480,23 @@ static bool bond_should_deliver_exact_match(struct sk_buff *skb,
         return false;
 }
 
-static struct sk_buff *bond_handle_frame(struct sk_buff *skb)
+static rx_handler_result_t bond_handle_frame(struct sk_buff **pskb)
 {
+        struct sk_buff *skb = *pskb;
         struct slave *slave;
         struct net_device *bond_dev;
         struct bonding *bond;
 
-        skb = skb_share_check(skb, GFP_ATOMIC);
-        if (unlikely(!skb))
-                return NULL;
-
         slave = bond_slave_get_rcu(skb->dev);
         bond_dev = ACCESS_ONCE(slave->dev->master);
         if (unlikely(!bond_dev))
-                return skb;
+                return RX_HANDLER_PASS;
+
+        skb = skb_share_check(skb, GFP_ATOMIC);
+        if (unlikely(!skb))
+                return RX_HANDLER_CONSUMED;
+
+        *pskb = skb;
 
         bond = netdev_priv(bond_dev);
 
@@ -1501,8 +1504,7 @@ static struct sk_buff *bond_handle_frame(struct sk_buff *skb)
                 slave->dev->last_rx = jiffies;
 
         if (bond_should_deliver_exact_match(skb, slave, bond)) {
-                skb->deliver_no_wcard = 1;
-                return skb;
+                return RX_HANDLER_EXACT;
         }
 
         skb->dev = bond_dev;
@@ -1514,12 +1516,12 @@ static struct sk_buff *bond_handle_frame(struct sk_buff *skb)
                 if (unlikely(skb_cow_head(skb,
                                           skb->data - skb_mac_header(skb)))) {
                         kfree_skb(skb);
-                        return NULL;
+                        return RX_HANDLER_CONSUMED;
                 }
                 memcpy(eth_hdr(skb)->h_dest, bond_dev->dev_addr, ETH_ALEN);
         }
 
-        return skb;
+        return RX_HANDLER_ANOTHER;
 }
 
 /* enslave device <slave> to bond device <master> */
diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index 497991bd3b64..5b37d3c191e4 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -152,9 +152,10 @@ static void macvlan_broadcast(struct sk_buff *skb,
 }
 
 /* called under rcu_read_lock() from netif_receive_skb */
-static struct sk_buff *macvlan_handle_frame(struct sk_buff *skb)
+static rx_handler_result_t macvlan_handle_frame(struct sk_buff **pskb)
 {
         struct macvlan_port *port;
+        struct sk_buff *skb = *pskb;
         const struct ethhdr *eth = eth_hdr(skb);
         const struct macvlan_dev *vlan;
         const struct macvlan_dev *src;
@@ -184,7 +185,7 @@ static struct sk_buff *macvlan_handle_frame(struct sk_buff *skb)
                          */
                         macvlan_broadcast(skb, port, src->dev,
                                           MACVLAN_MODE_VEPA);
-                return skb;
+                return RX_HANDLER_PASS;
         }
 
         if (port->passthru)
@@ -192,12 +193,12 @@ static struct sk_buff *macvlan_handle_frame(struct sk_buff *skb)
         else
                 vlan = macvlan_hash_lookup(port, eth->h_dest);
         if (vlan == NULL)
-                return skb;
+                return RX_HANDLER_PASS;
 
         dev = vlan->dev;
         if (unlikely(!(dev->flags & IFF_UP))) {
                 kfree_skb(skb);
-                return NULL;
+                return RX_HANDLER_CONSUMED;
         }
         len = skb->len + ETH_HLEN;
         skb = skb_share_check(skb, GFP_ATOMIC);
@@ -211,7 +212,7 @@ static struct sk_buff *macvlan_handle_frame(struct sk_buff *skb)
 
 out:
         macvlan_count_rx(vlan, len, ret == NET_RX_SUCCESS, 0);
-        return NULL;
+        return RX_HANDLER_CONSUMED;
 }
 
 static int macvlan_queue_xmit(struct sk_buff *skb, struct net_device *dev)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 604dbf5051d3..5eeb2cd3631c 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -390,7 +390,55 @@ enum gro_result {
 };
 typedef enum gro_result gro_result_t;
 
-typedef struct sk_buff *rx_handler_func_t(struct sk_buff *skb);
+/*
+ * enum rx_handler_result - Possible return values for rx_handlers.
+ * @RX_HANDLER_CONSUMED: skb was consumed by rx_handler, do not process it
+ * further.
+ * @RX_HANDLER_ANOTHER: Do another round in receive path. This is indicated in
+ * case skb->dev was changed by rx_handler.
+ * @RX_HANDLER_EXACT: Force exact delivery, no wildcard.
+ * @RX_HANDLER_PASS: Do nothing, passe the skb as if no rx_handler was called.
+ *
+ * rx_handlers are functions called from inside __netif_receive_skb(), to do
+ * special processing of the skb, prior to delivery to protocol handlers.
+ *
+ * Currently, a net_device can only have a single rx_handler registered. Trying
+ * to register a second rx_handler will return -EBUSY.
+ *
+ * To register a rx_handler on a net_device, use netdev_rx_handler_register().
+ * To unregister a rx_handler on a net_device, use
+ * netdev_rx_handler_unregister().
+ *
+ * Upon return, rx_handler is expected to tell __netif_receive_skb() what to
+ * do with the skb.
+ *
+ * If the rx_handler consumed to skb in some way, it should return
+ * RX_HANDLER_CONSUMED. This is appropriate when the rx_handler arranged for
+ * the skb to be delivered in some other ways.
+ *
+ * If the rx_handler changed skb->dev, to divert the skb to another
+ * net_device, it should return RX_HANDLER_ANOTHER. The rx_handler for the
+ * new device will be called if it exists.
+ *
+ * If the rx_handler consider the skb should be ignored, it should return
+ * RX_HANDLER_EXACT. The skb will only be delivered to protocol handlers that
+ * are registred on exact device (ptype->dev == skb->dev).
+ *
+ * If the rx_handler didn't changed skb->dev, but want the skb to be normally
+ * delivered, it should return RX_HANDLER_PASS.
+ *
+ * A device without a registered rx_handler will behave as if rx_handler
+ * returned RX_HANDLER_PASS.
+ */
+
+enum rx_handler_result {
+        RX_HANDLER_CONSUMED,
+        RX_HANDLER_ANOTHER,
+        RX_HANDLER_EXACT,
+        RX_HANDLER_PASS,
+};
+typedef enum rx_handler_result rx_handler_result_t;
+typedef rx_handler_result_t rx_handler_func_t(struct sk_buff **pskb);
 
 extern void __napi_schedule(struct napi_struct *n);
 
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 31f02d0b46a7..24cfa626931e 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -388,10 +388,7 @@ struct sk_buff {
         kmemcheck_bitfield_begin(flags2);
         __u16                   queue_mapping:16;
 #ifdef CONFIG_IPV6_NDISC_NODETYPE
-        __u8                    ndisc_nodetype:2,
-                                deliver_no_wcard:1;
-#else
-        __u8                    deliver_no_wcard:1;
+        __u8                    ndisc_nodetype:2;
 #endif
         __u8                    ooo_okay:1;
         kmemcheck_bitfield_end(flags2);
diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index 88e4aa9cb1f9..e2160792e1bc 100644
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -139,21 +139,22 @@ static inline int is_link_local(const unsigned char *dest)
  * Return NULL if skb is handled
  * note: already called with rcu_read_lock
  */
-struct sk_buff *br_handle_frame(struct sk_buff *skb)
+rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
 {
         struct net_bridge_port *p;
+        struct sk_buff *skb = *pskb;
         const unsigned char *dest = eth_hdr(skb)->h_dest;
         br_should_route_hook_t *rhook;
 
         if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
-                return skb;
+                return RX_HANDLER_PASS;
 
         if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
                 goto drop;
 
         skb = skb_share_check(skb, GFP_ATOMIC);
         if (!skb)
-                return NULL;
+                return RX_HANDLER_CONSUMED;
 
         p = br_port_get_rcu(skb->dev);
 
@@ -167,10 +168,12 @@ struct sk_buff *br_handle_frame(struct sk_buff *skb)
                         goto forward;
 
                 if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,
-                            NULL, br_handle_local_finish))
-                        return NULL;    /* frame consumed by filter */
-                else
-                        return skb;     /* continue processing */
+                            NULL, br_handle_local_finish)) {
+                        return RX_HANDLER_CONSUMED; /* consumed by filter */
+                } else {
+                        *pskb = skb;
+                        return RX_HANDLER_PASS; /* continue processing */
+                }
         }
 
 forward:
@@ -178,8 +181,10 @@ forward:
         case BR_STATE_FORWARDING:
                 rhook = rcu_dereference(br_should_route_hook);
                 if (rhook) {
-                        if ((*rhook)(skb))
-                                return skb;
+                        if ((*rhook)(skb)) {
+                                *pskb = skb;
+                                return RX_HANDLER_PASS;
+                        }
                         dest = eth_hdr(skb)->h_dest;
                 }
                 /* fall through */
@@ -194,5 +199,5 @@ forward:
 drop:
                 kfree_skb(skb);
         }
-        return NULL;
+        return RX_HANDLER_CONSUMED;
 }
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index f7afc364d777..19e2f46ed086 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -379,7 +379,7 @@ extern void br_features_recompute(struct net_bridge *br);
 
 /* br_input.c */
 extern int br_handle_frame_finish(struct sk_buff *skb);
-extern struct sk_buff *br_handle_frame(struct sk_buff *skb);
+extern rx_handler_result_t br_handle_frame(struct sk_buff **pskb);
 
 /* br_ioctl.c */
 extern int br_dev_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
diff --git a/net/core/dev.c b/net/core/dev.c
index 0d39032e9621..0b88eba97dab 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3070,6 +3070,8 @@ out:
  *      on a failure.
  *
  *      The caller must hold the rtnl_mutex.
+ *
+ *      For a general description of rx_handler, see enum rx_handler_result.
  */
 int netdev_rx_handler_register(struct net_device *dev,
                                rx_handler_func_t *rx_handler,
@@ -3129,6 +3131,7 @@ static int __netif_receive_skb(struct sk_buff *skb)
         rx_handler_func_t *rx_handler;
         struct net_device *orig_dev;
         struct net_device *null_or_dev;
+        bool deliver_exact = false;
         int ret = NET_RX_DROP;
         __be16 type;
 
@@ -3181,18 +3184,22 @@ ncls:
 
         rx_handler = rcu_dereference(skb->dev->rx_handler);
         if (rx_handler) {
-                struct net_device *prev_dev;
-
                 if (pt_prev) {
                         ret = deliver_skb(skb, pt_prev, orig_dev);
                         pt_prev = NULL;
                 }
-                prev_dev = skb->dev;
-                skb = rx_handler(skb);
-                if (!skb)
+                switch (rx_handler(&skb)) {
+                case RX_HANDLER_CONSUMED:
                         goto out;
-                if (skb->dev != prev_dev)
+                case RX_HANDLER_ANOTHER:
                         goto another_round;
+                case RX_HANDLER_EXACT:
+                        deliver_exact = true;
+                case RX_HANDLER_PASS:
+                        break;
+                default:
+                        BUG();
+                }
         }
 
         if (vlan_tx_tag_present(skb)) {
@@ -3210,7 +3217,7 @@ ncls:
         vlan_on_bond_hook(skb);
 
         /* deliver only exact match when indicated */
-        null_or_dev = skb->deliver_no_wcard ? skb->dev : NULL;
+        null_or_dev = deliver_exact ? skb->dev : NULL;
 
         type = skb->protocol;
         list_for_each_entry_rcu(ptype,
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 1eb526a848ff..801dd08908f9 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -523,7 +523,6 @@ static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
         new->ip_summed          = old->ip_summed;
         skb_copy_queue_mapping(new, old);
         new->priority           = old->priority;
-        new->deliver_no_wcard   = old->deliver_no_wcard;
 #if defined(CONFIG_IP_VS) || defined(CONFIG_IP_VS_MODULE)
         new->ipvs_property      = old->ipvs_property;
 #endif