--- a/programs/pluto/send.c
+++ b/programs/pluto/send.c
@@ -26,7 +26,7 @@
  *
  */
 
-#include <unistd.h>	/* for usleep() */
+#include <time.h>	/* for nanosleep() */
 #include <errno.h>
 
 #include "defs.h"
@@ -173,7 +173,8 @@ bool send_chunks(const char *where, bool just_a_keepalive,
 	/* Send a duplicate packet when this impair is enabled - used for testing */
 	if (IMPAIR(JACOB_TWO_TWO)) {
 		/* sleep for half a second, and second another packet */
-		usleep(500000);
+		const struct timespec req = {0, 500 * 1000 * 1000};
+		nanosleep(&req, NULL);
 		ip_endpoint_buf b;
 
 		DBG_log("JACOB 2-2: resending %zu bytes for %s through %s:%d to %s:",