- if (nlmsg_parse(cb->nlh, sizeof(struct ifinfomsg), tb, IFLA_MAX,
- ifla_policy) >= 0) {
+ /* A hack to preserve kernel<->userspace interface.
+ * The correct header is ifinfomsg. It is consistent with rtnl_getlink.
+ * However, before Linux v3.9 the code here assumed rtgenmsg and that's
+ * what iproute2 < v3.9.0 used.
+ * We can detect the old iproute2. Even including the IFLA_EXT_MASK
+ * attribute, its netlink message is shorter than struct ifinfomsg.
+ */
+ hdrlen = nlmsg_len(cb->nlh) < sizeof(struct ifinfomsg) ?
+ sizeof(struct rtgenmsg) : sizeof(struct ifinfomsg);
+
+ if (nlmsg_parse(cb->nlh, hdrlen, tb, IFLA_MAX, ifla_policy) >= 0) {