a

iputil.rkt

@@ -44,9 +44,10 @@
   (string-join parts "."))
 
 (define (ip-netmask ip)
+  (- 32
      (for/sum ([i (in-range 32)])
        #:break (positive? (bitwise-and ip (arithmetic-shift 1 i)))
-    1))
+       1)))
 
 (define (string->subnet str)
   (match-define (list ipstr maskstr) (string-split str "/"))