diff --git a/c_gen/templates/of_object.c b/c_gen/templates/of_object.c
index ae22f64..a328b3e 100644
--- a/c_gen/templates/of_object.c
+++ b/c_gen/templates/of_object.c
@@ -641,6 +641,47 @@
     obj->wire_object.wbuf = NULL;
 }
 
+#define _MAX_PARENT_ITERATIONS 4
+/**
+ * Iteratively update parent lengths thru hierarchy
+ * @param obj The object whose length is being updated
+ * @param delta The difference between the current and new lengths
+ *
+ * Note that this includes updating the object itself.  It will
+ * iterate thru parents.
+ *
+ * Assumes delta > 0.
+ */
+void
+of_object_parent_length_update(of_object_t *obj, int delta)
+{
+#ifndef NDEBUG
+    int count = 0;
+    of_wire_buffer_t *wbuf;  /* For debug asserts only */
+#endif
+
+    while (obj != NULL) {
+        ASSERT(count++ < _MAX_PARENT_ITERATIONS);
+        obj->length += delta;
+        if (obj->wire_length_set != NULL) {
+            obj->wire_length_set(obj, obj->length);
+        }
+#ifndef NDEBUG
+        wbuf = obj->wire_object.wbuf;
+#endif
+
+        /* Asserts for wire length checking */
+        ASSERT(obj->length + obj->wire_object.obj_offset <=
+               WBUF_CURRENT_BYTES(wbuf));
+        if (obj->parent == NULL) {
+            ASSERT(obj->length + obj->wire_object.obj_offset ==
+                   WBUF_CURRENT_BYTES(wbuf));
+        }
+
+        obj = obj->parent;
+    }
+}
+
 /*
  * Set member:
  *    get_wbuf_extent
diff --git a/c_gen/templates/of_object.h b/c_gen/templates/of_object.h
index fee95e1..a85e33e 100644
--- a/c_gen/templates/of_object.h
+++ b/c_gen/templates/of_object.h
@@ -192,6 +192,8 @@
 
 int of_object_can_grow(of_object_t *obj, int new_len);
 
+void of_object_parent_length_update(of_object_t *obj, int delta);
+
 struct of_object_s {
     /* The control block for the underlying data buffer */
     of_wire_object_t wire_object;