diff --git a/src/vlib/trace.c b/src/vlib/trace.c
index 49b521e..c6a0ef7 100644
--- a/src/vlib/trace.c
+++ b/src/vlib/trace.c
@@ -612,18 +612,6 @@
 {
 }
 
-int
-vnet_is_packet_traced (vlib_buffer_t * b,
-		       u32 classify_table_index, int func)
-__attribute__ ((weak));
-
-int
-vnet_is_packet_traced (vlib_buffer_t * b, u32 classify_table_index, int func)
-{
-  clib_warning ("BUG: STUB called");
-  return 1;
-}
-
 void *
 vlib_add_trace (vlib_main_t * vm,
 		vlib_node_runtime_t * r, vlib_buffer_t * b, u32 n_data_bytes)
@@ -631,8 +619,148 @@
   return vlib_add_trace_inline (vm, r, b, n_data_bytes);
 }
 
+vlib_is_packet_traced_fn_t *
+vlib_is_packet_traced_function_from_name (const char *name)
+{
+  vlib_trace_filter_function_registration_t *reg =
+    vlib_trace_filter_main.trace_filter_registration;
+  while (reg)
+    {
+      if (clib_strcmp (reg->name, name) == 0)
+	break;
+      reg = reg->next;
+    }
+  if (!reg)
+    return 0;
+  return reg->function;
+}
 
+static vlib_is_packet_traced_fn_t *
+vlib_is_packet_traced_default_function ()
+{
+  vlib_trace_filter_function_registration_t *reg =
+    vlib_trace_filter_main.trace_filter_registration;
+  vlib_trace_filter_function_registration_t *tmp_reg = reg;
+  while (reg)
+    {
+      if (reg->priority > tmp_reg->priority)
+	tmp_reg = reg;
+      reg = reg->next;
+    }
+  return tmp_reg->function;
+}
 
+static clib_error_t *
+vlib_trace_filter_function_init (vlib_main_t *vm)
+{
+  vlib_is_packet_traced_fn_t *default_fn =
+    vlib_is_packet_traced_default_function ();
+  foreach_vlib_main ()
+    {
+      vlib_trace_main_t *tm = &this_vlib_main->trace_main;
+      tm->current_trace_filter_function = default_fn;
+    }
+  return 0;
+}
+
+vlib_trace_filter_main_t vlib_trace_filter_main;
+
+VLIB_INIT_FUNCTION (vlib_trace_filter_function_init);
+
+static clib_error_t *
+show_trace_filter_function (vlib_main_t *vm, unformat_input_t *input,
+			    vlib_cli_command_t *cmd)
+{
+  vlib_trace_filter_main_t *tfm = &vlib_trace_filter_main;
+  vlib_trace_main_t *tm = &vm->trace_main;
+  vlib_is_packet_traced_fn_t *current_trace_filter_fn =
+    tm->current_trace_filter_function;
+  vlib_trace_filter_function_registration_t *reg =
+    tfm->trace_filter_registration;
+
+  while (reg)
+    {
+      vlib_cli_output (vm, "%sname:%s description: %s priority: %u",
+		       reg->function == current_trace_filter_fn ? "(*) " : "",
+		       reg->name, reg->description, reg->priority);
+      reg = reg->next;
+    }
+  return 0;
+}
+
+VLIB_CLI_COMMAND (show_trace_filter_function_cli, static) = {
+  .path = "show trace filter function",
+  .short_help = "show trace filter function",
+  .function = show_trace_filter_function,
+};
+
+uword
+unformat_vlib_trace_filter_function (unformat_input_t *input, va_list *args)
+{
+  vlib_is_packet_traced_fn_t **res =
+    va_arg (*args, vlib_is_packet_traced_fn_t **);
+  vlib_trace_filter_main_t *tfm = &vlib_trace_filter_main;
+
+  vlib_trace_filter_function_registration_t *reg =
+    tfm->trace_filter_registration;
+  while (reg)
+    {
+      if (unformat (input, reg->name))
+	{
+	  *res = reg->function;
+	  return 1;
+	}
+      reg = reg->next;
+    }
+  return 0;
+}
+
+void
+vlib_set_trace_filter_function (vlib_is_packet_traced_fn_t *x)
+{
+  foreach_vlib_main ()
+    {
+      this_vlib_main->trace_main.current_trace_filter_function = x;
+    }
+}
+
+static clib_error_t *
+set_trace_filter_function (vlib_main_t *vm, unformat_input_t *input,
+			   vlib_cli_command_t *cmd)
+{
+  unformat_input_t _line_input, *line_input = &_line_input;
+  vlib_is_packet_traced_fn_t *res = 0;
+  clib_error_t *error = 0;
+
+  if (!unformat_user (input, unformat_line_input, line_input))
+    return 0;
+
+  while (unformat_check_input (line_input) != (uword) UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (line_input, "%U", unformat_vlib_trace_filter_function,
+		    &res))
+	;
+      else
+	{
+	  error = clib_error_create (
+	    "expected valid trace filter function, got `%U'",
+	    format_unformat_error, line_input);
+	  goto done;
+	}
+    }
+  vlib_set_trace_filter_function (res);
+
+done:
+  unformat_free (line_input);
+
+  return error;
+}
+
+VLIB_CLI_COMMAND (set_trace_filter_function_cli, static) = {
+  .path = "set trace filter function",
+  .short_help = "set trace filter function <func_name>",
+  .function = set_trace_filter_function,
+};
 /*
  * fd.io coding-style-patch-verification: ON
  *
diff --git a/src/vlib/trace.h b/src/vlib/trace.h
index d045271..46256ce 100644
--- a/src/vlib/trace.h
+++ b/src/vlib/trace.h
@@ -80,6 +80,17 @@
 					   struct vlib_buffer_t * b,
 					   u32 n_data_bytes);
 
+typedef int (vlib_is_packet_traced_fn_t) (vlib_buffer_t *b,
+					  u32 classify_table_index, int func);
+typedef struct vlib_trace_filter_function_registration
+{
+  const char *name;
+  const char *description;
+  int priority;
+  vlib_is_packet_traced_fn_t *function;
+  struct vlib_trace_filter_function_registration *next;
+} vlib_trace_filter_function_registration_t;
+
 typedef struct
 {
   /* Pool of trace buffers. */
@@ -109,9 +120,32 @@
   /* a callback to enable customized addition of a new trace */
   vlib_add_trace_callback_t *add_trace_callback;
 
+  vlib_is_packet_traced_fn_t *current_trace_filter_function;
+
 } vlib_trace_main_t;
 
 format_function_t format_vlib_trace;
+typedef struct
+{
+  vlib_trace_filter_function_registration_t *trace_filter_registration;
+} vlib_trace_filter_main_t;
+
+extern vlib_trace_filter_main_t vlib_trace_filter_main;
+#define VLIB_REGISTER_TRACE_FILTER_FUNCTION(x, ...)                           \
+  __VA_ARGS__ vlib_trace_filter_function_registration_t                       \
+    __vlib_trace_filter_function_##x;                                         \
+  static void __clib_constructor                                              \
+    __vlib_trace_filter_function_registration_##x (void)                      \
+  {                                                                           \
+    vlib_trace_filter_main_t *tfm = &vlib_trace_filter_main;                  \
+    __vlib_trace_filter_function_##x.next = tfm->trace_filter_registration;   \
+    tfm->trace_filter_registration = &__vlib_trace_filter_function_##x;       \
+  }                                                                           \
+  __VA_ARGS__ vlib_trace_filter_function_registration_t                       \
+    __vlib_trace_filter_function_##x
+
+vlib_is_packet_traced_fn_t *
+vlib_is_packet_traced_function_from_name (const char *name);
 
 void trace_apply_filter (struct vlib_main_t *vm);
 int trace_time_cmp (void *a1, void *a2);
@@ -121,6 +155,9 @@
 				   u32 filter, u8 verbose);
 void trace_filter_set (u32 node_index, u32 flag, u32 count);
 void clear_trace_buffer (void);
+void vlib_set_trace_filter_function (vlib_is_packet_traced_fn_t *x);
+uword unformat_vlib_trace_filter_function (unformat_input_t *input,
+					   va_list *args);
 
 #endif /* included_vlib_trace_h */
 
diff --git a/src/vlib/trace_funcs.h b/src/vlib/trace_funcs.h
index 3ed4768..9b45346 100644
--- a/src/vlib/trace_funcs.h
+++ b/src/vlib/trace_funcs.h
@@ -138,10 +138,7 @@
   nf->flags |= VLIB_FRAME_TRACE;
 }
 
-void trace_apply_filter (vlib_main_t * vm);
-int vnet_is_packet_traced (vlib_buffer_t * b,
-			   u32 classify_table_index, int func);
-
+void trace_apply_filter (vlib_main_t *vm);
 
 /*
  * Mark buffer as traced and allocate trace buffer.
@@ -164,7 +161,7 @@
   if (PREDICT_FALSE (vlib_global_main.trace_filter.trace_filter_enable))
     {
       /* See if we're supposed to trace this packet... */
-      if (vnet_is_packet_traced (
+      if (tm->current_trace_filter_function (
 	    b, vlib_global_main.trace_filter.classify_table_index,
 	    0 /* full classify */) != 1)
 	return 0;