1 files changed, 25 insertions, 1 deletions

diff --git a/include/linux/netlink.h b/include/linux/netlink.h
index da14ab61f363..60e7137f840d 100644
--- a/include/linux/netlink.h
+++ b/include/linux/netlink.h
@@ -62,11 +62,35 @@ netlink_kernel_create(struct net *net, int unit, struct netlink_kernel_cfg *cfg)
         return __netlink_kernel_create(net, unit, THIS_MODULE, cfg);
 }
 
+/**
+ * struct netlink_ext_ack - netlink extended ACK report struct
+ * @_msg: message string to report - don't access directly, use
+ *      %NL_SET_ERR_MSG
+ * @bad_attr: attribute with error
+ */
+struct netlink_ext_ack {
+        const char *_msg;
+        const struct nlattr *bad_attr;
+};
+
+/* Always use this macro, this allows later putting the
+ * message into a separate section or such for things
+ * like translation or listing all possible messages.
+ * Currently string formatting is not supported (due
+ * to the lack of an output buffer.)
+ */
+#define NL_SET_ERR_MSG(extack, msg) do {        \
+        static const char _msg[] = (msg);       \
+                                                \
+        (extack)->_msg = _msg;                  \
+} while (0)
+
 extern void netlink_kernel_release(struct sock *sk);
 extern int __netlink_change_ngroups(struct sock *sk, unsigned int groups);
 extern int netlink_change_ngroups(struct sock *sk, unsigned int groups);
 extern void __netlink_clear_multicast_users(struct sock *sk, unsigned int group);
-extern void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err);
+extern void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
+                        const struct netlink_ext_ack *extack);
 extern int netlink_has_listeners(struct sock *sk, unsigned int group);
 
 extern int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 portid, int nonblock);