+static LIST_HEAD(rtnl_af_ops);
+
+static const struct rtnl_af_ops *rtnl_af_lookup(const int family)
+{
+ const struct rtnl_af_ops *ops;
+
+ list_for_each_entry(ops, &rtnl_af_ops, list) {
+ if (ops->family == family)
+ return ops;
+ }
+
+ return NULL;
+}
+
+/**
+ * __rtnl_af_register - Register rtnl_af_ops with rtnetlink.
+ * @ops: struct rtnl_af_ops * to register
+ *
+ * The caller must hold the rtnl_mutex.
+ *
+ * Returns 0 on success or a negative error code.
+ */
+int __rtnl_af_register(struct rtnl_af_ops *ops)
+{
+ list_add_tail(&ops->list, &rtnl_af_ops);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(__rtnl_af_register);
+
+/**
+ * rtnl_af_register - Register rtnl_af_ops with rtnetlink.
+ * @ops: struct rtnl_af_ops * to register
+ *
+ * Returns 0 on success or a negative error code.
+ */
+int rtnl_af_register(struct rtnl_af_ops *ops)
+{
+ int err;
+
+ rtnl_lock();
+ err = __rtnl_af_register(ops);
+ rtnl_unlock();
+ return err;
+}
+EXPORT_SYMBOL_GPL(rtnl_af_register);
+
+/**
+ * __rtnl_af_unregister - Unregister rtnl_af_ops from rtnetlink.
+ * @ops: struct rtnl_af_ops * to unregister
+ *
+ * The caller must hold the rtnl_mutex.
+ */
+void __rtnl_af_unregister(struct rtnl_af_ops *ops)
+{
+ list_del(&ops->list);
+}
+EXPORT_SYMBOL_GPL(__rtnl_af_unregister);
+
+/**
+ * rtnl_af_unregister - Unregister rtnl_af_ops from rtnetlink.
+ * @ops: struct rtnl_af_ops * to unregister
+ */
+void rtnl_af_unregister(struct rtnl_af_ops *ops)
+{
+ rtnl_lock();
+ __rtnl_af_unregister(ops);
+ rtnl_unlock();
+}
+EXPORT_SYMBOL_GPL(rtnl_af_unregister);
+
+static size_t rtnl_link_get_af_size(const struct net_device *dev)
+{
+ struct rtnl_af_ops *af_ops;
+ size_t size;
+
+ /* IFLA_AF_SPEC */
+ size = nla_total_size(sizeof(struct nlattr));
+
+ list_for_each_entry(af_ops, &rtnl_af_ops, list) {
+ if (af_ops->get_link_af_size) {
+ /* AF_* + nested data */
+ size += nla_total_size(sizeof(struct nlattr)) +
+ af_ops->get_link_af_size(dev);
+ }
+ }
+
+ return size;
+}
+