netdev - Re: [PATCH net-next v2 5/6] tcp: rstreason: introduce SK_RST_REASON_TCP

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Message-ID: <CAL+tcoAopVMG8ddjjASA6s1=6zJ6Wps3Lv5xDq+7LeCRMzGFVA@mail.gmail.com>
Date: Thu, 1 Aug 2024 17:30:14 +0800
From: Jason Xing <kerneljasonxing@...il.com>
To: Eric Dumazet <edumazet@...gle.com>
Cc: davem@...emloft.net, kuba@...nel.org, pabeni@...hat.com, 
	dsahern@...nel.org, kuniyu@...zon.com, netdev@...r.kernel.org, 
	Jason Xing <kernelxing@...cent.com>
Subject: Re: [PATCH net-next v2 5/6] tcp: rstreason: introduce
 SK_RST_REASON_TCP_TIMEOUT for active reset

Hello Eric,

On Thu, Aug 1, 2024 at 2:58 PM Eric Dumazet <edumazet@...gle.com> wrote:
>
> On Wed, Jul 31, 2024 at 2:10 PM Jason Xing <kerneljasonxing@...il.com> wrote:
> >
> > From: Jason Xing <kernelxing@...cent.com>
> >
> > Whether user sets TCP_USER_TIMEOUT option or not, when we find there
> > is no left chance to proceed, we will send an RST to the other side.
> >
>
> Not sure why you mention TCP_USER_TIMEOUT here.
>
> > Signed-off-by: Jason Xing <kernelxing@...cent.com>
> > ---
> > v2
> > Link: https://lore.kernel.org/all/CAL+tcoB-12pUS0adK8M_=C97aXewYYmDA6rJKLXvAXEHvEsWjA@mail.gmail.com/
> > 1. correct the comment and changelog
> > ---
> >  include/net/rstreason.h | 8 ++++++++
> >  net/ipv4/tcp_timer.c    | 2 +-
> >  2 files changed, 9 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/net/rstreason.h b/include/net/rstreason.h
> > index bbf20d0bbde7..739ad1db4212 100644
> > --- a/include/net/rstreason.h
> > +++ b/include/net/rstreason.h
> > @@ -21,6 +21,7 @@
> >         FN(TCP_ABORT_ON_LINGER)         \
> >         FN(TCP_ABORT_ON_MEMORY)         \
> >         FN(TCP_STATE)                   \
> > +       FN(TCP_TIMEOUT)                 \
> >         FN(MPTCP_RST_EUNSPEC)           \
> >         FN(MPTCP_RST_EMPTCP)            \
> >         FN(MPTCP_RST_ERESOURCE)         \
> > @@ -108,6 +109,13 @@ enum sk_rst_reason {
> >          * Please see RFC 9293 for all possible reset conditions
> >          */
> >         SK_RST_REASON_TCP_STATE,
> > +       /**
> > +        * @SK_RST_REASON_TCP_TIMEOUT: time to timeout
> > +        * Whether user sets TCP_USER_TIMEOUT options or not, when we
> > +        * have already run out of all the chances, we have to reset the
> > +        * connection
> > +        */
> > +       SK_RST_REASON_TCP_TIMEOUT,
> >
> >         /* Copy from include/uapi/linux/mptcp.h.
> >          * These reset fields will not be changed since they adhere to
> > diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
> > index 3910f6d8614e..bd403300e4c4 100644
> > --- a/net/ipv4/tcp_timer.c
> > +++ b/net/ipv4/tcp_timer.c
> > @@ -807,7 +807,7 @@ static void tcp_keepalive_timer (struct timer_list *t)
> >                     (user_timeout == 0 &&
> >                     icsk->icsk_probes_out >= keepalive_probes(tp))) {
> >                         tcp_send_active_reset(sk, GFP_ATOMIC,
> > -                                             SK_RST_REASON_NOT_SPECIFIED);
> > +                                             SK_RST_REASON_TCP_TIMEOUT);
> >                         tcp_write_err(sk);
> >                         goto out;
> >                 }
> > --
> > 2.37.3
> >
>
> This is more about keepalive really. You should use a better name
> reflecting that it is a keepalive timeout.

I think you're right. Let me use 'TCP_KEEPALIVE_TIMEOUT' then.

Thanks,
Jason