ipsec: Record the number of packets lost from an SA

Type: feature

Gaps in the sequence numbers received on an SA indicate packets that were lost.
Gaps are identified using the anti-replay window that records the sequences seen.

Publish the number of lost packets in the stats segment at /net/ipsec/sa/lost

Signed-off-by: Neale Ranns <neale@graphiant.com>
Change-Id: I8af1c09b7b25a705e18bf82e1623b3ce19e5a74d
diff --git a/src/vlib/counter.h b/src/vlib/counter.h
index 9f56542..56701e8 100644
--- a/src/vlib/counter.h
+++ b/src/vlib/counter.h
@@ -64,6 +64,20 @@
 /** The number of counters (not the number of per-thread counters) */
 u32 vlib_simple_counter_n_counters (const vlib_simple_counter_main_t * cm);
 
+/** Pre-fetch a per-thread simple counter for the given object index */
+always_inline void
+vlib_prefetch_simple_counter (const vlib_simple_counter_main_t *cm,
+			      u32 thread_index, u32 index)
+{
+  counter_t *my_counters;
+
+  /*
+   * This CPU's index is assumed to already be in cache
+   */
+  my_counters = cm->counters[thread_index];
+  clib_prefetch_store (my_counters + index);
+}
+
 /** Increment a simple counter
     @param cm - (vlib_simple_counter_main_t *) simple counter main pointer
     @param thread_index - (u32) the current cpu index