[PATCH bpf-next v2 2/3] tcp: add keepalive_time_set helper

[Dmitry Yakunin <zeil@xxxxxxxxxxxxxx>]

This is preparation for usage in bpf_setsockopt.

v2:
  - change first parameter type to struct sock (Eric Dumazet)

Signed-off-by: Dmitry Yakunin <zeil@xxxxxxxxxxxxxx>
Acked-by: Martin KaFai Lau <kafai@xxxxxx>
---
 include/net/tcp.h | 18 ++++++++++++++++++
 net/ipv4/tcp.c    | 15 ++-------------
 2 files changed, 20 insertions(+), 13 deletions(-)

diff --git a/include/net/tcp.h b/include/net/tcp.h
index b681338..e0a815f 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1465,6 +1465,24 @@ static inline u32 keepalive_time_elapsed(const struct tcp_sock *tp)
 			  tcp_jiffies32 - tp->rcv_tstamp);
 }
 
+/* val must be validated at the top level function */
+static inline void keepalive_time_set(struct sock *sk, int val)
+{
+	struct tcp_sock *tp = tcp_sk(sk);
+
+	tp->keepalive_time = val * HZ;
+	if (sock_flag(sk, SOCK_KEEPOPEN) &&
+	    !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) {
+		u32 elapsed = keepalive_time_elapsed(tp);
+
+		if (tp->keepalive_time > elapsed)
+			elapsed = tp->keepalive_time - elapsed;
+		else
+			elapsed = 0;
+		inet_csk_reset_keepalive_timer(sk, elapsed);
+	}
+}
+
 static inline int tcp_fin_time(const struct sock *sk)
 {
 	int fin_timeout = tcp_sk(sk)->linger2 ? : sock_net(sk)->ipv4.sysctl_tcp_fin_timeout;
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 9700649..a366ab7 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3003,19 +3003,8 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
 	case TCP_KEEPIDLE:
 		if (val < 1 || val > MAX_TCP_KEEPIDLE)
 			err = -EINVAL;
-		else {
-			tp->keepalive_time = val * HZ;
-			if (sock_flag(sk, SOCK_KEEPOPEN) &&
-			    !((1 << sk->sk_state) &
-			      (TCPF_CLOSE | TCPF_LISTEN))) {
-				u32 elapsed = keepalive_time_elapsed(tp);
-				if (tp->keepalive_time > elapsed)
-					elapsed = tp->keepalive_time - elapsed;
-				else
-					elapsed = 0;
-				inet_csk_reset_keepalive_timer(sk, elapsed);
-			}
-		}
+		else
+			keepalive_time_set(sk, val);
 		break;
 	case TCP_KEEPINTVL:
 		if (val < 1 || val > MAX_TCP_KEEPINTVL)
-- 
2.7.4