Add VLIB_NODE_FN() macro to simplify multiversioning of node functions

Change-Id: Ibab5e27277f618ceb2d543b9d6a1a5f191e7d1db
Signed-off-by: Damjan Marion <damarion@cisco.com>

2 files changed, 48 insertions, 0 deletions

diff --git a/src/vlib/node.c b/src/vlib/node.c
index 17dd2ea87d4..cc1732bb90d 100644
--- a/src/vlib/node.c
+++ b/src/vlib/node.c
@@ -324,6 +324,26 @@ register_node (vlib_main_t * vm, vlib_node_registration_t * r)
       ASSERT (VLIB_NODE_TYPE_INTERNAL == zero.type);
     }
 
+  if (r->node_fn_registrations)
+    {
+      vlib_node_fn_registration_t *fnr = r->node_fn_registrations;
+      int priority = -1;
+
+      /* to avoid confusion, please remove ".function " statiement from
+         CLIB_NODE_REGISTRATION() if using function function candidates */
+      ASSERT (r->function == 0);
+
+      while (fnr)
+	{
+	  if (fnr->priority > priority)
+	    {
+	      priority = fnr->priority;
+	      r->function = fnr->function;
+	    }
+	  fnr = fnr->next_registration;
+	}
+    }
+
   ASSERT (r->function != 0);
 
   n = clib_mem_alloc_no_fail (sizeof (n[0]));
diff --git a/src/vlib/node.h b/src/vlib/node.h
index 7177bebeffb..67eaea3f0e8 100644
--- a/src/vlib/node.h
+++ b/src/vlib/node.h
@@ -75,11 +75,21 @@ typedef enum
   VLIB_N_NODE_TYPE,
 } vlib_node_type_t;
 
+typedef struct _vlib_node_fn_registration
+{
+  vlib_node_function_t *function;
+  int priority;
+  struct _vlib_node_fn_registration *next_registration;
+} vlib_node_fn_registration_t;
+
 typedef struct _vlib_node_registration
 {
   /* Vector processing function for this node. */
   vlib_node_function_t *function;
 
+  /* Node function candidate registration with priority */
+  vlib_node_fn_registration_t *node_fn_registrations;
+
   /* Node name. */
   char *name;
 
@@ -160,6 +170,24 @@ static void __vlib_rm_node_registration_##x (void)                      \
 }                                                                       \
 __VA_ARGS__ vlib_node_registration_t x
 
+#define VLIB_NODE_FN(node)						\
+uword CLIB_MARCH_SFX (node##_fn)();					\
+static vlib_node_fn_registration_t					\
+  CLIB_MARCH_SFX(node##_fn_registration) =				\
+  { .function = &CLIB_MARCH_SFX (node##_fn), };				\
+									\
+static void __clib_constructor						\
+CLIB_MARCH_SFX (node##_multiarch_register) (void)			\
+{									\
+  extern vlib_node_registration_t node;					\
+  vlib_node_fn_registration_t *r;					\
+  r = & CLIB_MARCH_SFX (node##_fn_registration);			\
+  r->priority = CLIB_MARCH_FN_PRIORITY();				\
+  r->next_registration = node.node_fn_registrations;			\
+  node.node_fn_registrations = r;					\
+}									\
+uword CLIB_CPU_OPTIMIZED CLIB_MARCH_SFX (node##_fn)
+
 #if CLIB_DEBUG > 0
 #define VLIB_NODE_FUNCTION_CLONE_TEMPLATE(arch, fn)
 #define VLIB_NODE_FUNCTION_MULTIARCH_CLONE(fn)