dpif-netdev: Avoid sending probe packets

When ofproto probe for datapath features, no packets should actually
be sent to the network. This pactch fixes the userspace by dropping
probe packets before action execution.

Signed-off-by: Andy Zhou <azhou@ovn.org>
Acked-by: Jarno Rajahalme <jarno@ovn.org>

lib/dpif-netdev.c

@@ -2660,6 +2660,13 @@ dpif_netdev_execute(struct dpif *dpif, struct dpif_execute *execute)
         }
     }
 
+    if (execute->probe) {
+        /* If this is part of a probe, Drop the packet, since executing
+         * the action may actually cause spurious packets be sent into
+         * the network. */
+        return 0;
+    }
+
     /* If the current thread is non-pmd thread, acquires
      * the 'non_pmd_mutex'. */
     if (pmd->core_id == NON_PMD_CORE_ID) {