diff --git a/src/libnm-glib-aux/nm-shared-utils.h b/src/libnm-glib-aux/nm-shared-utils.h
index 20810e4cd5..81c7260612 100644
--- a/src/libnm-glib-aux/nm-shared-utils.h
+++ b/src/libnm-glib-aux/nm-shared-utils.h
@@ -508,8 +508,16 @@ gboolean nm_utils_ip_is_site_local(int addr_family, const void *address);
 
 /*****************************************************************************/
 
-#define NM_IPV4LL_NETWORK ((in_addr_t) (htonl(0xA9FE0000lu)))
-#define NM_IPV4LL_NETMASK ((in_addr_t) (htonl(0xFFFF0000lu)))
+#define NM_IPV4LL_NETWORK ((in_addr_t) htonl(0xA9FE0000lu))
+#define NM_IPV4LL_NETMASK ((in_addr_t) htonl(0xFFFF0000lu))
+
+static inline gboolean
+nm_utils_ip4_address_is_loopback(in_addr_t addr)
+{
+    /* There is also IN_LOOPBACK() in <linux/in.h>, but there the
+     * argument is in host order not `in_addr_t`. */
+    return (addr & htonl(0xFF000000u)) == htonl(0x7F000000u);
+}
 
 static inline gboolean
 nm_utils_ip4_address_is_link_local(in_addr_t addr)