[PATCH 2/2] tcp: fix FIN_WAIT2 timer expression in /proc/net/tcp

[Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>]

When tcp_fin_timeout is greater than 60, /proc/net/tcp shows
FIN_WAIT2 keepalive timer as expires in (tcp_fin_timeout - 60)
sec. This is confusing because the timer is not for keepalive
and the socket needs another timewait timer to disappear.

Signed-off-by: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
---
 net/ipv4/tcp_ipv4.c |   23 +++++++++++++++--------
 net/ipv6/tcp_ipv6.c |   23 +++++++++++++++--------
 2 files changed, 30 insertions(+), 16 deletions(-)

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 629937d..32bde0e 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2656,17 +2656,24 @@ static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
 	int rx_queue;
 
 	if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
-		timer_active	= 1;
-		timer_expires	= icsk->icsk_timeout;
+		timer_active		= 1;
+		timer_expires		= icsk->icsk_timeout;
 	} else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
-		timer_active	= 4;
-		timer_expires	= icsk->icsk_timeout;
+		timer_active		= 4;
+		timer_expires		= icsk->icsk_timeout;
 	} else if (timer_pending(&sk->sk_timer)) {
-		timer_active	= 2;
-		timer_expires	= sk->sk_timer.expires;
+		if (sk->sk_state == TCP_FIN_WAIT2 && sock_flag(sk, SOCK_DEAD)) {
+			timer_active	= 3;
+			timer_expires	= sk->sk_timer.expires +
+					  (tp->linger2 >= 0 ?
+					   TCP_TIMEWAIT_LEN : 0);
+		} else {
+			timer_active	= 2;
+			timer_expires	= sk->sk_timer.expires;
+		}
 	} else {
-		timer_active	= 0;
-		timer_expires = jiffies;
+		timer_active		= 0;
+		timer_expires		= jiffies;
 	}
 
 	if (sk->sk_state == TCP_LISTEN)
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 93825dd..3af4f9d 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1795,17 +1795,24 @@ static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
 	srcp  = ntohs(inet->inet_sport);
 
 	if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
-		timer_active	= 1;
-		timer_expires	= icsk->icsk_timeout;
+		timer_active		= 1;
+		timer_expires		= icsk->icsk_timeout;
 	} else if (icsk->icsk_pending == ICSK_TIME_PROBE0) {
-		timer_active	= 4;
-		timer_expires	= icsk->icsk_timeout;
+		timer_active		= 4;
+		timer_expires		= icsk->icsk_timeout;
 	} else if (timer_pending(&sp->sk_timer)) {
-		timer_active	= 2;
-		timer_expires	= sp->sk_timer.expires;
+		if (sp->sk_state == TCP_FIN_WAIT2 && sock_flag(sp, SOCK_DEAD)) {
+			timer_active	= 3;
+			timer_expires	= sp->sk_timer.expires +
+					  (tp->linger2 >= 0 ?
+					   TCP_TIMEWAIT_LEN : 0);
+		} else {
+			timer_active	= 2;
+			timer_expires	= sp->sk_timer.expires;
+		}
 	} else {
-		timer_active	= 0;
-		timer_expires = jiffies;
+		timer_active		= 0;
+		timer_expires		= jiffies;
 	}
 
 	seq_printf(seq,
-- 
1.7.1