diff --git a/openbsc/src/libmsc/silent_call.c b/openbsc/src/libmsc/silent_call.c
index e9ece18..131a178 100644
--- a/openbsc/src/libmsc/silent_call.c
+++ b/openbsc/src/libmsc/silent_call.c
@@ -95,7 +95,8 @@
 int silent_call_reroute(struct gsm_subscriber_connection *conn, struct msgb *msg)
 {
 	struct gsm48_hdr *gh = msgb_l3(msg);
-	uint8_t pdisc = gh->proto_discr & 0x0f;
+	uint8_t pdisc = gsm48_hdr_pdisc(gh);
+	uint8_t msg_type = gsm48_hdr_msg_type(gh);
 	int i;
 
 	/* if we're not part of a silent call, never reroute */
@@ -105,7 +106,7 @@
 	/* check if we are a special message that is handled in openbsc */
 	for (i = 0; i < ARRAY_SIZE(silent_call_accept); i++) {
 		if (silent_call_accept[i].pdisc == pdisc &&
-		    silent_call_accept[i].msg_type == gh->msg_type)
+		    silent_call_accept[i].msg_type == msg_type)
 			return 0;
 	}