diff --git a/guix/build/syscalls.scm b/guix/build/syscalls.scm
index 00d8ceb4803c031ebfafcb70c9acdcc1d464439a..4ee2b97e76d98a914a498214aa9046c8b7b4325b 100644
--- a/guix/build/syscalls.scm
+++ b/guix/build/syscalls.scm
@@ -5,6 +5,7 @@
;;; Copyright © 2017 Mathieu Othacehe <m.othacehe@gmail.com>
;;; Copyright © 2019 Guillaume Le Vaillant <glv@posteo.net>
;;; Copyright © 2020 Julien Lepiller <julien@lepiller.eu>
+;;; Copyright © 2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
;;;
;;; This file is part of GNU Guix.
;;;
@@ -1205,6 +1206,8 @@ (define (thread-name)
;;;
(define SIOCGIFCONF ;from <bits/ioctls.h>
+ ; <net/if.h>
+ ; <hurd/ioctl.h>
(if (string-contains %host-type "linux")
#x8912 ;GNU/Linux
#xf00801a4)) ;GNU/Hurd
@@ -1215,23 +1218,23 @@ (define SIOCGIFFLAGS
(define SIOCSIFFLAGS
(if (string-contains %host-type "linux")
#x8914 ;GNU/Linux
- -1)) ;FIXME: GNU/Hurd?
+ #x84804190)) ;GNU/Hurd
(define SIOCGIFADDR
(if (string-contains %host-type "linux")
#x8915 ;GNU/Linux
- -1)) ;FIXME: GNU/Hurd?
+ #xc08401a1)) ;GNU/Hurd
(define SIOCSIFADDR
(if (string-contains %host-type "linux")
#x8916 ;GNU/Linux
- -1)) ;FIXME: GNU/Hurd?
+ #x8084018c)) ;GNU/Hurd
(define SIOCGIFNETMASK
(if (string-contains %host-type "linux")
#x891b ;GNU/Linux
- -1)) ;FIXME: GNU/Hurd?
+ #xc08401a5)) ;GNU/Hurd
(define SIOCSIFNETMASK
(if (string-contains %host-type "linux")
#x891c ;GNU/Linux
- -1)) ;FIXME: GNU/Hurd?
+ #x80840196)) ;GNU/Hurd
(define SIOCADDRT
(if (string-contains %host-type "linux")
#x890B ;GNU/Linux