--- libelwix/src/crc.c	2024/10/28 09:55:57	1.8.2.1
+++ libelwix/src/crc.c	2024/10/29 01:22:08	1.9.4.1
@@ -3,7 +3,7 @@
 *  by Michael Pounov <misho@openbsd-bg.org>
 *
 * $Author: misho $
-* $Id: crc.c,v 1.8.2.1 2024/10/28 09:55:57 misho Exp $
+* $Id: crc.c,v 1.9.4.1 2024/10/29 01:22:08 misho Exp $
 *
 **************************************************************************
 The ELWIX and AITNET software is distributed under the following
@@ -313,6 +313,8 @@ crcIP(u_short* __restrict buf, int len)
 u_short
 crcTCP(struct in_addr src, struct in_addr dst, u_char * __restrict th)
 {
+	assert(th);
+
 	struct psd_tcp {
 		struct in_addr src;
 		struct in_addr dst;
@@ -343,6 +345,8 @@ crcTCP(struct in_addr src, struct in_addr dst, u_char 
 u_short
 crcUDP(struct in_addr src, struct in_addr dst, u_char * __restrict uh)
 {
+	assert(uh);
+
 	struct psd_udp {
 		struct in_addr src;
 		struct in_addr dst;