1 files changed, 8 insertions, 0 deletions

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 3f87fd87bc9c..fb5c66b2ab81 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1033,6 +1033,14 @@ static inline int keepalive_probes(const struct tcp_sock *tp)
         return tp->keepalive_probes ? : sysctl_tcp_keepalive_probes;
 }
 
+static inline u32 keepalive_time_elapsed(const struct tcp_sock *tp)
+{
+        const struct inet_connection_sock *icsk = &tp->inet_conn;
+
+        return min_t(u32, tcp_time_stamp - icsk->icsk_ack.lrcvtime,
+                          tcp_time_stamp - tp->rcv_tstamp);
+}
+
 static inline int tcp_fin_time(const struct sock *sk)
 {
         int fin_timeout = tcp_sk(sk)->linger2 ? : sysctl_tcp_fin_timeout;