netlink: extended ACK reporting

Add the base infrastructure and UAPI for netlink extended ACK
reporting. All "manual" calls to netlink_ack() pass NULL for now and
thus don't get extended ACK reporting.

Big thanks goes to Pablo Neira Ayuso for not only bringing up the
whole topic at netconf (again) but also coming up with the nlattr
passing trick and various other ideas.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 1 deletions

diff --git a/include/net/netlink.h b/include/net/netlink.h
index b239fcd33d80..a064ec3e2ee1 100644
--- a/include/net/netlink.h
+++ b/include/net/netlink.h
@@ -233,7 +233,8 @@ struct nl_info {
 };
 
 int netlink_rcv_skb(struct sk_buff *skb,
-                    int (*cb)(struct sk_buff *, struct nlmsghdr *));
+                    int (*cb)(struct sk_buff *, struct nlmsghdr *,
+                              struct netlink_ext_ack *));
 int nlmsg_notify(struct sock *sk, struct sk_buff *skb, u32 portid,
                  unsigned int group, int report, gfp_t flags);