+static int rtnl_fill_link_af(struct sk_buff *skb,
+ const struct net_device *dev,
+ u32 ext_filter_mask)
+{
+ const struct rtnl_af_ops *af_ops;
+ struct nlattr *af_spec;
+
+ af_spec = nla_nest_start(skb, IFLA_AF_SPEC);
+ if (!af_spec)
+ return -EMSGSIZE;
+
+ list_for_each_entry(af_ops, &rtnl_af_ops, list) {
+ struct nlattr *af;
+ int err;
+
+ if (!af_ops->fill_link_af)
+ continue;
+
+ af = nla_nest_start(skb, af_ops->family);
+ if (!af)
+ return -EMSGSIZE;
+
+ err = af_ops->fill_link_af(skb, dev, ext_filter_mask);
+ /*
+ * Caller may return ENODATA to indicate that there
+ * was no data to be dumped. This is not an error, it
+ * means we should trim the attribute header and
+ * continue.
+ */
+ if (err == -ENODATA)
+ nla_nest_cancel(skb, af);
+ else if (err < 0)
+ return -EMSGSIZE;
+
+ nla_nest_end(skb, af);
+ }
+
+ nla_nest_end(skb, af_spec);
+ return 0;
+}
+