diff --git a/inany.h b/inany.h
index 52d43f2..7ff32f0 100644
--- a/inany.h
+++ b/inany.h
@@ -6,8 +6,6 @@
  *           IPv6 or IPv4 (encoded as IPv4-mapped IPv6 addresses)
  */
 
-#include <assert.h>
-
 /** union inany_addr - Represents either an IPv4 or IPv6 address
  * @a6:			Address as an IPv6 address, may be IPv4-mapped
  * @v4mapped.zero:	All zero-bits for an IPv4 address
@@ -63,7 +61,7 @@ static inline void inany_from_af(union inany_addr *aa, int af, const void *addr)
 		aa->v4mapped.a4 = *((struct in_addr *)addr);
 	} else {
 		/* Not valid to call with other address families */
-		assert(0);
+		ASSERT(0);
 	}
 }
 
@@ -89,6 +87,6 @@ static inline void inany_from_sockaddr(union inany_addr *aa, in_port_t *port,
 		*port = ntohs(sa4->sin_port);
 	} else {
 		/* Not valid to call with other address families */
-		assert(0);
+		ASSERT(0);
 	}
 }
diff --git a/lineread.c b/lineread.c
index 59021e6..6ffb14e 100644
--- a/lineread.c
+++ b/lineread.c
@@ -16,10 +16,10 @@
 #include <fcntl.h>
 #include <string.h>
 #include <stdbool.h>
-#include <assert.h>
 #include <unistd.h>
 
 #include "lineread.h"
+#include "util.h"
 
 /**
  * lineread_init() - Prepare for line by line file reading without allocation
@@ -44,10 +44,10 @@ static int peek_line(struct lineread *lr, bool eof)
 	char *nl;
 
 	/* Sanity checks (which also document invariants) */
-	assert(lr->count >= 0);
-	assert(lr->next_line >= 0);
-	assert(lr->next_line + lr->count >= lr->next_line);
-	assert(lr->next_line + lr->count <= LINEREAD_BUFFER_SIZE);
+	ASSERT(lr->count >= 0);
+	ASSERT(lr->next_line >= 0);
+	ASSERT(lr->next_line + lr->count >= lr->next_line);
+	ASSERT(lr->next_line + lr->count <= LINEREAD_BUFFER_SIZE);
 
 	nl = memchr(lr->buf + lr->next_line, '\n', lr->count);
 
diff --git a/tcp.c b/tcp.c
index dfa8b6d..8424d8e 100644
--- a/tcp.c
+++ b/tcp.c
@@ -288,7 +288,6 @@
 #include <sys/uio.h>
 #include <unistd.h>
 #include <time.h>
-#include <assert.h>
 
 #include <linux/tcp.h> /* For struct tcp_info */
 
@@ -588,7 +587,7 @@ static inline struct tcp_tap_conn *conn_at_idx(int index)
 {
 	if ((index < 0) || (index >= TCP_MAX_CONNS))
 		return NULL;
-	assert(!(CONN(index)->c.spliced));
+	ASSERT(!(CONN(index)->c.spliced));
 	return CONN(index);
 }
 
@@ -2695,7 +2694,7 @@ static void tcp_conn_from_sock(struct ctx *c, union epoll_ref ref,
 	socklen_t sl;
 	int s;
 
-	assert(ref.r.p.tcp.tcp.listen);
+	ASSERT(ref.r.p.tcp.tcp.listen);
 
 	if (c->tcp.conn_count >= TCP_MAX_CONNS)
 		return;
@@ -2937,7 +2936,7 @@ static void tcp_ns_sock_init4(const struct ctx *c, in_port_t port)
 	struct in_addr loopback = { htonl(INADDR_LOOPBACK) };
 	int s;
 
-	assert(c->mode == MODE_PASTA);
+	ASSERT(c->mode == MODE_PASTA);
 
 	s = sock_l4(c, AF_INET, IPPROTO_TCP, &loopback, NULL, port, tref.u32);
 	if (s >= 0)
@@ -2961,7 +2960,7 @@ static void tcp_ns_sock_init6(const struct ctx *c, in_port_t port)
 				     .tcp.index = idx };
 	int s;
 
-	assert(c->mode == MODE_PASTA);
+	ASSERT(c->mode == MODE_PASTA);
 
 	s = sock_l4(c, AF_INET6, IPPROTO_TCP, &in6addr_loopback, NULL, port,
 		    tref.u32);
diff --git a/tcp_splice.c b/tcp_splice.c
index 72b1672..1d624f1 100644
--- a/tcp_splice.c
+++ b/tcp_splice.c
@@ -46,7 +46,6 @@
 #include <sys/epoll.h>
 #include <sys/types.h>
 #include <sys/socket.h>
-#include <assert.h>
 
 #include "util.h"
 #include "passt.h"
@@ -519,7 +518,7 @@ bool tcp_splice_conn_from_sock(struct ctx *c, union epoll_ref ref,
 	union inany_addr aany;
 	in_port_t port;
 
-	assert(c->mode == MODE_PASTA);
+	ASSERT(c->mode == MODE_PASTA);
 
 	inany_from_sockaddr(&aany, &port, sa);
 	a4 = inany_v4(&aany);
diff --git a/udp.c b/udp.c
index adb47e8..2e9b7e6 100644
--- a/udp.c
+++ b/udp.c
@@ -108,7 +108,6 @@
 #include <sys/uio.h>
 #include <unistd.h>
 #include <time.h>
-#include <assert.h>
 
 #include "checksum.h"
 #include "util.h"
@@ -248,7 +247,7 @@ static void udp_invert_portmap(struct udp_port_fwd *fwd)
 {
 	int i;
 
-	assert(ARRAY_SIZE(fwd->f.delta) == ARRAY_SIZE(fwd->rdelta));
+	ASSERT(ARRAY_SIZE(fwd->f.delta) == ARRAY_SIZE(fwd->rdelta));
 	for (i = 0; i < ARRAY_SIZE(fwd->f.delta); i++) {
 		in_port_t delta = fwd->f.delta[i];
 
diff --git a/util.c b/util.c
index d9858f2..c5ee1c0 100644
--- a/util.c
+++ b/util.c
@@ -23,7 +23,6 @@
 #include <time.h>
 #include <errno.h>
 #include <stdbool.h>
-#include <assert.h>
 
 #include "util.h"
 #include "passt.h"
diff --git a/util.h b/util.h
index 4a1c03e..6303c17 100644
--- a/util.h
+++ b/util.h
@@ -6,6 +6,11 @@
 #ifndef UTIL_H
 #define UTIL_H
 
+#include <stdlib.h>
+#include <stdarg.h>
+
+#include "log.h"
+
 #define VERSION_BLOB							       \
 	VERSION "\n"							       \
 	"Copyright Red Hat\n"						       \
@@ -47,6 +52,18 @@
 #define STRINGIFY(x)	#x
 #define STR(x)		STRINGIFY(x)
 
+#define ASSERT(expr)							\
+	do {								\
+		if (!(expr)) {						\
+			err("ASSERTION FAILED in %s (%s:%d): %s",	\
+			    __func__, __FILE__, __LINE__, STRINGIFY(expr)); \
+			/* This may actually SIGSYS, due to seccomp,	\
+			 * but that will still get the job done		\
+			 */						\
+			abort();					\
+		}							\
+	} while (0)
+
 #ifdef P_tmpdir
 #define TMPDIR		P_tmpdir
 #else
@@ -134,7 +151,8 @@ int do_clone(int (*fn)(void *), char *stack_area, size_t stack_size, int flags,
 
 #include <net/if.h>
 #include <limits.h>
-#include <stdarg.h>
+#include <stdint.h>
+#include <netinet/ip6.h>
 
 #include "packet.h"