diff --git a/modules/dtls_gw/rtpp_dtls_conn.c b/modules/dtls_gw/rtpp_dtls_conn.c
index 423881273..c03e9673c 100644
--- a/modules/dtls_gw/rtpp_dtls_conn.c
+++ b/modules/dtls_gw/rtpp_dtls_conn.c
@@ -482,7 +482,12 @@ rtpp_dtls_conn_rtp_send(struct rtpp_dtls_conn *self, struct pkt_proc_ctx *pktxp)
 static int
 rtpp_dtls_conn_srtp_recv(struct rtpp_dtls_conn *self, struct pkt_proc_ctx *pktxp)
 {
-    int status, len;
+    int status;
+#if defined(SRTP_PROTECT_LASTARG)
+    SRTP_PROTECT_LASTARG len;
+#else
+    size_t len;
+#endif
     struct rtpp_dtls_conn_priv *pvt;
 
     PUB2PVT(self, pvt);