diff --git a/src/client.h b/src/client.h
new file mode 100644
index 0000000..3046f8b
--- /dev/null
+++ b/src/client.h
@@ -0,0 +1,49 @@
+#pragma once
+
+#include <osmocom/core/fsm.h>
+#include <osmocom/abis/ipa.h>
+
+#include "rspro_util.h"
+
+enum {
+	DMAIN,
+};
+
+/* fsm.c */
+
+enum bankd_conn_fsm_event {
+	BDC_E_TCP_UP,
+	BDC_E_TCP_DOWN,
+	BDC_E_CLIENT_CONN_RES,
+};
+
+
+enum server_conn_fsm_event {
+	SRVC_E_TCP_UP,
+	SRVC_E_TCP_DOWN,
+	SRVC_E_CLIENT_CONN_RES,
+};
+
+extern struct osmo_fsm remsim_client_bankd_fsm;
+extern struct osmo_fsm remsim_client_server_fsm;
+
+/* main.c */
+
+struct bankd_client {
+	/* connection to the remsim-server (control) */
+	struct ipa_client_conn *srv_conn;
+	struct osmo_fsm_inst *srv_fi;
+
+	/* our own component ID */
+	struct app_comp_id own_comp_id;
+
+	/* connection to the remsim-bankd */
+	char *bankd_host;
+	uint16_t bankd_port;
+	struct ipa_client_conn *bankd_conn;
+	struct osmo_fsm_inst *bankd_fi;
+};
+
+void bankd_send_rspro(struct bankd_client *bc, RsproPDU_t *rspro);
+int bankd_read_cb(struct ipa_client_conn *conn, struct msgb *msg);
+int bankd_conn_fsm_alloc(struct bankd_client *bc);