diff --git a/lib/if_rmap.c b/lib/if_rmap.c
index e6f753c..ddc62fd 100644
--- a/lib/if_rmap.c
+++ b/lib/if_rmap.c
@@ -120,13 +120,12 @@
 }
 
 static int
-if_rmap_hash_cmp (void *arg1, void* arg2)
+if_rmap_hash_cmp (const void *arg1, const void* arg2)
 {
-  struct if_rmap *if_rmap1 = arg1;
-  struct if_rmap *if_rmap2 = arg2;
-  if (strcmp (if_rmap1->ifname, if_rmap2->ifname) == 0)
-    return 1;
-  return 0;
+  const struct if_rmap *if_rmap1 = arg1;
+  const struct if_rmap *if_rmap2 = arg2;
+
+  return strcmp (if_rmap1->ifname, if_rmap2->ifname) == 0;
 }
 
 static struct if_rmap *