diff --git a/ip/iproute.c b/ip/iproute.c
index 5dc4437..2c2a331 100644
--- a/ip/iproute.c
+++ b/ip/iproute.c
@@ -92,7 +92,7 @@
 
 static struct
 {
-	int tb;
+	unsigned int tb;
 	int cloned;
 	int flushed;
 	char *flushb;