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Message-ID: <alpine.DEB.2.00.1004270906320.13989@melkinpaasi.cs.helsinki.fi>
Date: Tue, 27 Apr 2010 09:08:08 +0300 (EEST)
From: "Ilpo Järvinen" <ilpo.jarvinen@...sinki.fi>
To: Flavio Leitner <fleitner@...hat.com>
cc: Netdev <netdev@...r.kernel.org>,
David Miller <davem@...emloft.net>,
Eric Dumazet <eric.dumazet@...il.com>
Subject: Re: [PATCH v4] TCP: avoid to send keepalive probes if receiving
data
On Tue, 27 Apr 2010, Flavio Leitner wrote:
> 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 <fleitner@...hat.com>
> ---
> 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 75be5a2..305810e 100644
> --- a/include/net/tcp.h
> +++ b/include/net/tcp.h
> @@ -1032,6 +1032,14 @@ 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 0f8caf6..48a6f33 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 8a0ab29..a9155f9 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)) {
Thanks. Looks very nice now.
Acked-by: Ilpo Järvinen <ilpo.jarvinen@...sinki.fi>
--
i.
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