+/* Prefixes 'size' zeroed bytes to the head end of 'b'. 'b' must have at least
+ * 'size' bytes of headroom. Returns a pointer to the first byte of the data's
+ * location in the ofpbuf. */
+void *
+ofpbuf_push_zeros(struct ofpbuf *b, size_t size)
+{
+ void *dst = ofpbuf_push_uninit(b, size);
+ memset(dst, 0, size);
+ return dst;
+}
+