diff --git a/bgpd/bgp_aspath.h b/bgpd/bgp_aspath.h
index aa13daa..c8f929f 100644
--- a/bgpd/bgp_aspath.h
+++ b/bgpd/bgp_aspath.h
@@ -103,7 +103,7 @@
 extern int aspath_confed_check (struct aspath *);
 extern int aspath_left_confed_check (struct aspath *);
 extern unsigned long aspath_count (void);
-extern unsigned int aspath_count_hops (struct aspath *);
+extern unsigned int aspath_count_hops (const struct aspath *);
 extern unsigned int aspath_count_confeds (struct aspath *);
 extern unsigned int aspath_size (struct aspath *);
 extern as_t aspath_highest (struct aspath *);