M3UA: Respond with "Unexpected Message" if ASPTM is received too soon

This was discovered (and fix validated) using m3ua-sgp-aspsm-i-003
of Michale Tuexen's m3ua-testtool.

Change-Id: I8b63e7b5e39a7ef8dd66bf014110a04f5f3dc2a2

1 files changed, 2 insertions, 1 deletions

diff --git a/src/m3ua.c b/src/m3ua.c
index 7ae6dcf..7291d0d 100644
--- a/src/m3ua.c
+++ b/src/m3ua.c
@@ -623,7 +623,8 @@ static int m3ua_rx_asp(struct osmo_ss7_asp *asp, struct xua_msg *xua)
 		return M3UA_ERR_UNSUPP_MSG_TYPE;
 
 	/* deliver that event to the ASP FSM */
-	osmo_fsm_inst_dispatch(asp->fi, event, xua);
+	if (osmo_fsm_inst_dispatch(asp->fi, event, xua) < 0)
+		return M3UA_ERR_UNEXPECTED_MSG;
 
 	return 0;
 }