diff --git a/include/re_shim.h b/include/re_shim.h
new file mode 100644
index 0000000..f5966a6
--- /dev/null
+++ b/include/re_shim.h
@@ -0,0 +1,15 @@
+
+
+/* RFC 4571 */
+
+
+enum { SHIM_HDR_SIZE = 2 };
+
+struct shim;
+
+typedef bool (shim_frame_h)(struct mbuf *mb, void *arg);
+
+
+int shim_insert(struct shim **shimp, struct tcp_conn *tc, int layer,
+		shim_frame_h *frameh, void *arg);
+int shim_debug(struct re_printf *pf, const struct shim *shim);