From mboxrd@z Thu Jan 1 00:00:00 1970 From: Flavio Leitner Subject: [PATCH v3] TCP: avoid to send keepalive probes if receiving data Date: Sun, 25 Apr 2010 23:40:59 -0300 Message-ID: <1272249659-2292-1-git-send-email-fleitner@redhat.com> References: <20100425235549.GB2550@sysclose.org> Cc: David Miller , Ilpo , Eric Dumazet , Flavio Leitner To: netdev@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:21099 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752076Ab0DZClg (ORCPT ); Sun, 25 Apr 2010 22:41:36 -0400 In-Reply-To: <20100425235549.GB2550@sysclose.org> Sender: netdev-owner@vger.kernel.org List-ID: 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 --- net/ipv4/tcp.c | 5 ++++- net/ipv4/tcp_timer.c | 8 ++++++++ 2 files changed, 12 insertions(+), 1 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 0f8caf6..94f605c 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2298,7 +2298,10 @@ 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 = min_t(u32, + tcp_time_stamp - icsk->icsk_ack.lrcvtime, + tcp_time_stamp - tp->rcv_tstamp); + 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 8a0ab29..9d1bb6f 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -554,6 +554,14 @@ static void tcp_keepalive_timer (unsigned long data) if (tp->packets_out || tcp_send_head(sk)) goto resched; + elapsed = tcp_time_stamp - icsk->icsk_ack.lrcvtime; + + /* receiving data means alive */ + if (elapsed < keepalive_time_when(tp)) { + elapsed = keepalive_time_when(tp) - elapsed; + goto resched; + } + elapsed = tcp_time_stamp - tp->rcv_tstamp; if (elapsed >= keepalive_time_when(tp)) { -- 1.5.5.6