[RTNETLINK]: Add rtnetlink notification interface

Adds rtnl_notify() to send rtnetlink notification messages and
rtnl_set_sk_err() to report notification errors as socket
errors in order to indicate the need of a resync due to loss
of events.

nlmsg_report() is added to properly document the meaning of
NLM_F_ECHO.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 18 insertions, 0 deletions

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index e02fa6a33f42..2b1af17e6389 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -171,6 +171,22 @@ int rtnl_unicast(struct sk_buff *skb, u32 pid)
         return nlmsg_unicast(rtnl, skb, pid);
 }
 
+int rtnl_notify(struct sk_buff *skb, u32 pid, u32 group,
+                struct nlmsghdr *nlh, gfp_t flags)
+{
+        int report = 0;
+
+        if (nlh)
+                report = nlmsg_report(nlh);
+
+        return nlmsg_notify(rtnl, skb, pid, group, report, flags);
+}
+
+void rtnl_set_sk_err(u32 group, int error)
+{
+        netlink_set_err(rtnl, 0, group, error);
+}
+
 int rtnetlink_put_metrics(struct sk_buff *skb, u32 *metrics)
 {
         struct rtattr *mx = (struct rtattr*)skb->tail;
@@ -829,3 +845,5 @@ EXPORT_SYMBOL(rtnl_lock);
 EXPORT_SYMBOL(rtnl_trylock);
 EXPORT_SYMBOL(rtnl_unlock);
 EXPORT_SYMBOL(rtnl_unicast);
+EXPORT_SYMBOL(rtnl_notify);
+EXPORT_SYMBOL(rtnl_set_sk_err);