+
+/* We limit the number of times that we pass into execute_actions()
+ * to avoid blowing out the stack in the event that we have a loop. */
+#define MAX_LOOPS 5
+
+struct loop_counter {
+ u8 count; /* Count. */
+ bool looping; /* Loop detected? */
+};
+
+static DEFINE_PER_CPU(struct loop_counter, loop_counters);
+
+static int loop_suppress(struct datapath *dp, struct sw_flow_actions *actions)
+{
+ if (net_ratelimit())
+ pr_warn("%s: flow looped %d times, dropping\n",
+ dp_name(dp), MAX_LOOPS);
+ actions->actions_len = 0;
+ return -ELOOP;
+}
+
+/* Execute a list of actions against 'skb'. */
+int execute_actions(struct datapath *dp, struct sk_buff *skb)
+{
+ struct sw_flow_actions *acts = rcu_dereference(OVS_CB(skb)->flow->sf_acts);
+ struct loop_counter *loop;
+ int error;
+
+ /* Check whether we've looped too much. */
+ loop = &__get_cpu_var(loop_counters);
+ if (unlikely(++loop->count > MAX_LOOPS))
+ loop->looping = true;
+ if (unlikely(loop->looping)) {
+ error = loop_suppress(dp, acts);
+ kfree_skb(skb);
+ goto out_loop;
+ }
+
+ OVS_CB(skb)->tun_id = 0;
+ error = do_execute_actions(dp, skb, acts->actions,
+ acts->actions_len, false);
+
+ /* Check whether sub-actions looped too much. */
+ if (unlikely(loop->looping))
+ error = loop_suppress(dp, acts);
+
+out_loop:
+ /* Decrement loop counter. */
+ if (!--loop->count)
+ loop->looping = false;
+
+ return error;
+}