--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mncc/struct.h	Sun Jun 26 16:31:47 2022 -0800
@@ -0,0 +1,29 @@
+/*
+ * This header file defines internal data structures
+ * for ThemWi MNCC daemon, talking to OsmoMSC.
+ */
+
+#ifndef	__STRUCT_H
+#define	__STRUCT_H
+
+struct socket_conn {
+	int	fd;
+	unsigned ncalls;
+	struct socket_conn *next;
+};
+
+/* GSM call leg on MNCC-MSC side, either MO or MT */
+struct gsm_call {
+	/* always present */
+	uint32_t callref;
+	/* only for internal switching */
+	struct gsm_call *other_leg;
+	/* only for external calls */
+	struct socket_conn *socket;
+	uint32_t socket_ref;
+	/* linked list management */
+	int gc_flag;
+	struct gsm_call *next;
+};
+
+#endif	/* include guard */