diff --git a/include/osmocom/core/Makefile.am b/include/osmocom/core/Makefile.am
index 3c30362..1ef3769 100644
--- a/include/osmocom/core/Makefile.am
+++ b/include/osmocom/core/Makefile.am
@@ -1,6 +1,6 @@
 osmocore_HEADERS = signal.h linuxlist.h timer.h select.h msgb.h bits.h \
 		   bitvec.h statistics.h utils.h socket.h \
-		   gsmtap.h write_queue.h \
+		   gsmtap.h write_queue.h prim.h \
 		   logging.h rate_ctr.h gsmtap_util.h \
 		   plugin.h crc16.h panic.h process.h msgfile.h \
 		   backtrace.h conv.h application.h
diff --git a/include/osmocom/core/prim.h b/include/osmocom/core/prim.h
new file mode 100644
index 0000000..5494f3c
--- /dev/null
+++ b/include/osmocom/core/prim.h
@@ -0,0 +1,20 @@
+#ifndef OSMO_PRIMITIVE_H
+#define OSMO_PRIMITIVE_H
+
+#include <stdint.h>
+
+enum osmo_prim_operation {
+	PRIM_OP_REQUEST,
+	PRIM_OP_RESPONSE,
+	PRIM_OP_INDICATION,
+	PRIM_OP_CONFIRM,
+};
+
+struct osmo_prim_hdr {
+	unsigned int sap;
+	unsigned int primitive;
+	enum osmo_prim_operation operation;
+	struct msgb *msg;	/* message containing associated data */
+};
+
+#endif