net: introduce rx_handler results and logic around that

This patch allows rx_handlers to better signalize what to do next to
it's caller. That makes skb->deliver_no_wcard no longer needed.

kernel-doc for rx_handler_result is taken from Nicolas' patch.

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Reviewed-by: Nicolas de Pesloüan <nicolas.2p.debian@free.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 14 insertions, 7 deletions

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,