From 6c37e5de456987f5bc80879afde05aa120784095 Mon Sep 17 00:00:00 2001 From: Flavio Leitner Date: Mon, 26 Apr 2010 18:33:27 +0000 Subject: [PATCH] TCP: avoid to send keepalive probes if receiving data MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit RFC 1122 says the following: ... Keep-alive packets MUST only be sent when no data or acknowledgement packets have been received for the connection within an interval. ... The acknowledgement packet is reseting the keepalive timer but the data packet isn't. This patch fixes it by checking the timestamp of the last received data packet too when the keepalive timer expires. Signed-off-by: Flavio Leitner Signed-off-by: Eric Dumazet Acked-by: Ilpo Järvinen Signed-off-by: David S. Miller --- include/net/tcp.h | 8 ++++++++ net/ipv4/tcp.c | 2 +- net/ipv4/tcp_timer.c | 4 ++-- 3 files changed, 11 insertions(+), 3 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; diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 6689c61cab47..8ce29747ad9b 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2298,7 +2298,7 @@ static int do_tcp_setsockopt(struct sock *sk, int level, if (sock_flag(sk, SOCK_KEEPOPEN) && !((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))) { - __u32 elapsed = tcp_time_stamp - tp->rcv_tstamp; + u32 elapsed = keepalive_time_elapsed(tp); if (tp->keepalive_time > elapsed) elapsed = tp->keepalive_time - elapsed; else diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index c732be00606b..440a5c6004f6 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -517,7 +517,7 @@ static void tcp_keepalive_timer (unsigned long data) struct sock *sk = (struct sock *) data; struct inet_connection_sock *icsk = inet_csk(sk); struct tcp_sock *tp = tcp_sk(sk); - __u32 elapsed; + u32 elapsed; /* Only process if socket is not in use. */ bh_lock_sock(sk); @@ -554,7 +554,7 @@ static void tcp_keepalive_timer (unsigned long data) if (tp->packets_out || tcp_send_head(sk)) goto resched; - elapsed = tcp_time_stamp - tp->rcv_tstamp; + elapsed = keepalive_time_elapsed(tp); if (elapsed >= keepalive_time_when(tp)) { if (icsk->icsk_probes_out >= keepalive_probes(tp)) { -- 2.20.1