NAT64: Run nat64-expire-worker-walk only when NAT64 is configured (VPP-1162)

Change-Id: Ic5e8d74bf5ac84cce5661de44778c89541c67636
Signed-off-by: Matus Fabian <matfabia@cisco.com>
diff --git a/src/plugins/nat/nat64.c b/src/plugins/nat/nat64.c
index 571e071..0b7536f 100644
--- a/src/plugins/nat/nat64.c
+++ b/src/plugins/nat/nat64.c
@@ -232,6 +232,8 @@
   nm->tcp_est_timeout = SNAT_TCP_ESTABLISHED_TIMEOUT;
   nm->tcp_incoming_syn_timeout = SNAT_TCP_INCOMING_SYN;
 
+  nm->total_enabled_count = 0;
+
   /* Set up the interface address add/del callback */
   cb4.function = nat64_ip4_add_del_interface_address_cb;
   cb4.function_opaque = 0;
@@ -430,6 +432,12 @@
 	interface->flags |= NAT_INTERFACE_FLAG_IS_INSIDE;
       else
 	interface->flags |= NAT_INTERFACE_FLAG_IS_OUTSIDE;
+
+      nm->total_enabled_count++;
+      vlib_process_signal_event (nm->sm->vlib_main,
+				 nm->nat64_expire_walk_node_index,
+				 NAT64_CLEANER_RESCHEDULE, 0);
+
     }
   else
     {
@@ -443,6 +451,8 @@
 	  ~NAT_INTERFACE_FLAG_IS_OUTSIDE;
       else
 	pool_put (nm->interfaces, interface);
+
+      nm->total_enabled_count--;
     }
 
   if (!is_inside)
@@ -1164,6 +1174,8 @@
 };
 /* *INDENT-ON* */
 
+static vlib_node_registration_t nat64_expire_walk_node;
+
 /**
  * @brief Centralized process to drive per worker expire walk.
  */
@@ -1171,8 +1183,12 @@
 nat64_expire_walk_fn (vlib_main_t * vm, vlib_node_runtime_t * rt,
 		      vlib_frame_t * f)
 {
+  nat64_main_t *nm = &nat64_main;
   vlib_main_t **worker_vms = 0, *worker_vm;
   int i;
+  uword event_type, *event_data = 0;
+
+  nm->nat64_expire_walk_node_index = nat64_expire_walk_node.index;
 
   if (vec_len (vlib_mains) == 0)
     vec_add1 (worker_vms, vm);
@@ -1188,8 +1204,28 @@
 
   while (1)
     {
-      vlib_process_wait_for_event_or_clock (vm, 10.0);
-      vlib_process_get_events (vm, NULL);
+      if (nm->total_enabled_count)
+	{
+	  vlib_process_wait_for_event_or_clock (vm, 10.0);
+	  event_type = vlib_process_get_events (vm, &event_data);
+	}
+      else
+	{
+	  vlib_process_wait_for_event (vm);
+	  event_type = vlib_process_get_events (vm, &event_data);
+	}
+
+      switch (event_type)
+	{
+	case ~0:
+	  break;
+	case NAT64_CLEANER_RESCHEDULE:
+	  break;
+	default:
+	  clib_warning ("unknown event %u", event_type);
+	  break;
+	}
+
       for (i = 0; i < vec_len (worker_vms); i++)
 	{
 	  worker_vm = worker_vms[i];
@@ -1201,8 +1237,6 @@
   return 0;
 }
 
-static vlib_node_registration_t nat64_expire_walk_node;
-
 /* *INDENT-OFF* */
 VLIB_REGISTER_NODE (nat64_expire_walk_node, static) = {
     .function = nat64_expire_walk_fn,
diff --git a/src/plugins/nat/nat64.h b/src/plugins/nat/nat64.h
index d9d3d76..e2334a5 100644
--- a/src/plugins/nat/nat64.h
+++ b/src/plugins/nat/nat64.h
@@ -39,6 +39,11 @@
 #undef _
 } nat64_tcp_ses_state_t;
 
+enum
+{
+  NAT64_CLEANER_RESCHEDULE = 1,
+} nat64_cleaner_process_event_e;
+
 typedef struct
 {
   ip6_address_t prefix;
@@ -99,6 +104,11 @@
   u32 tcp_est_timeout;
   u32 tcp_incoming_syn_timeout;
 
+  /* Total count of interfaces enabled */
+  u32 total_enabled_count;
+  /* The process node which orcherstrates the cleanup */
+  u32 nat64_expire_walk_node_index;
+
   ip4_main_t *ip4_main;
   snat_main_t *sm;
 } nat64_main_t;