diff --git a/lib/sockunion.h b/lib/sockunion.h
index 1a0a3c9..b9f3514 100644
--- a/lib/sockunion.h
+++ b/lib/sockunion.h
@@ -88,6 +88,7 @@
 extern int sockunion_cmp (union sockunion *, union sockunion *);
 extern int sockunion_same (union sockunion *, union sockunion *);
 
+extern union sockunion *sockunion_str2su (const char *str);
 extern int sockunion_accept (int sock, union sockunion *);
 extern int sockunion_stream_socket (union sockunion *);
 extern int sockopt_reuseaddr (int);