diff --git a/src/libnm-core-impl/nm-utils.c b/src/libnm-core-impl/nm-utils.c
index d1590a7a5..3c4cbc651 100644
--- a/src/libnm-core-impl/nm-utils.c
+++ b/src/libnm-core-impl/nm-utils.c
@@ -1571,12 +1571,7 @@ nm_utils_ip4_routes_from_variant(GVariant *value)
 guint32
 nm_utils_ip4_netmask_to_prefix(guint32 netmask)
 {
-    G_STATIC_ASSERT_EXPR(__SIZEOF_INT__ == 4);
-    G_STATIC_ASSERT_EXPR(sizeof(int) == 4);
-    G_STATIC_ASSERT_EXPR(sizeof(guint) == 4);
-    G_STATIC_ASSERT_EXPR(sizeof(netmask) == 4);
-
-    return ((netmask != 0u) ? (guint32) (32 - __builtin_ctz(ntohl(netmask))) : 0u);
+    return _nm_utils_ip4_netmask_to_prefix(netmask);
 }
 
 /**
diff --git a/src/libnm-glib-aux/nm-shared-utils.h b/src/libnm-glib-aux/nm-shared-utils.h
index fddcc8fe2..6cdc8875e 100644
--- a/src/libnm-glib-aux/nm-shared-utils.h
+++ b/src/libnm-glib-aux/nm-shared-utils.h
@@ -389,6 +389,17 @@ gboolean nm_utils_get_ipv6_interface_identifier(NMLinkType          link_type,
 
 /*****************************************************************************/
 
+static inline guint32
+_nm_utils_ip4_netmask_to_prefix(in_addr_t subnetmask)
+{
+    G_STATIC_ASSERT_EXPR(__SIZEOF_INT__ == 4);
+    G_STATIC_ASSERT_EXPR(sizeof(int) == 4);
+    G_STATIC_ASSERT_EXPR(sizeof(guint) == 4);
+    G_STATIC_ASSERT_EXPR(sizeof(subnetmask) == 4);
+
+    return ((subnetmask != 0u) ? (guint32) (32 - __builtin_ctz(ntohl(subnetmask))) : 0u);
+}
+
 /**
  * _nm_utils_ip4_prefix_to_netmask:
  * @prefix: a CIDR prefix