From: "Pengcheng Yang" <yangpc@wangsu.com>
To: "'Eric Dumazet'" <edumazet@google.com>,
"'Jakub Kicinski'" <kuba@kernel.org>
Cc: "'David Miller'" <davem@davemloft.net>,
"'netdev'" <netdev@vger.kernel.org>
Subject: Re: [PATCH net] tcp: fix TCP_SKB_CB(skb)->tcp_tw_isn not being used
Date: Fri, 15 Jan 2021 11:03:27 +0800 [thread overview]
Message-ID: <000501d6eaea$ff921960$feb64c20$@wangsu.com> (raw)
In-Reply-To: <CANn89iK5N-u-DKLmAF4+RSiG1g4Y1YkcizTX5h12hsTdpMt0DA@mail.gmail.com>
On Fri, Jan 15, 2021 at 1:12 AM Eric Dumazet <edumazet@google.com> wrote:
>
> On Thu, Jan 14, 2021 at 5:53 PM Jakub Kicinski <kuba@kernel.org> wrote:
> >
> > On Tue, 29 Dec 2020 05:59:20 +0800 Pengcheng Yang wrote:
> > > TCP_SKB_CB(skb)->tcp_tw_isn contains an ISN, chosen by
> > > tcp_timewait_state_process() , when SYN is received in TIMEWAIT state.
> > > But tcp_tw_isn is not used because it is overwritten by
> > > tcp_v4_restore_cb() after commit eeea10b83a13 ("tcp: add
> > > tcp_v4_fill_cb()/tcp_v4_restore_cb()").
> > >
> > > To fix this case, we record tcp_tw_isn before tcp_v4_restore_cb() and
> > > then set it in tcp_v4_fill_cb(). V6 does the same.
> > >
> > > Fixes: eeea10b83a13 ("tcp: add tcp_v4_fill_cb()/tcp_v4_restore_cb()")
> > > Reported-by: chenc <chenc9@wangsu.com>
> > > Signed-off-by: Pengcheng Yang <yangpc@wangsu.com>
> >
> > Please fix the date and resend. This patch came in last night,
> > but it has a date of December 28th.
>
> Not this whole madness about tcp_v4_fill_cb()/tcp_v4_restore_cb()
> could be reverted
This makes isn always been 0 in tcp_conn_request(), because tcp_tw_isn
is always initialized to 0 in tcp_v4_fill_cb() and tcp_tw_isn becomes meaningless.
Do we need to make tcp_tw_isn work again?
> now we have an RB tree for out-of-order packets.
I don't quite understand how setting tcp_tw_isn for SYN would affect
out_of_order_queue?
prev parent reply other threads:[~2021-01-15 3:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-28 21:59 [PATCH net] tcp: fix TCP_SKB_CB(skb)->tcp_tw_isn not being used Pengcheng Yang
2021-01-14 16:53 ` Jakub Kicinski
2021-01-14 17:11 ` Eric Dumazet
2021-01-15 3:03 ` Pengcheng Yang [this message]
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