netdev - Re: [PATCH v2 net-next] tcp: avoid reusing FIN_WAIT2 when trying to find port in connect() process

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Message-ID: <CAL+tcoDnaVVGVgTxwqYnYZvc8ErD62hGB=HNOU6_3Mwo7M6cSQ@mail.gmail.com>
Date: Tue, 20 Aug 2024 20:50:19 +0800
From: Jason Xing <kerneljasonxing@...il.com>
To: Paolo Abeni <pabeni@...hat.com>
Cc: davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org, 
	dsahern@...nel.org, ncardwell@...gle.com, kuniyu@...zon.com, 
	netdev@...r.kernel.org, Jason Xing <kernelxing@...cent.com>, 
	Jade Dong <jadedong@...cent.com>
Subject: Re: [PATCH v2 net-next] tcp: avoid reusing FIN_WAIT2 when trying to
 find port in connect() process

Hello Paolo,

On Tue, Aug 20, 2024 at 7:04 PM Paolo Abeni <pabeni@...hat.com> wrote:
>
> On 8/15/24 13:37, Jason Xing wrote:
> > From: Jason Xing <kernelxing@...cent.com>
> >
> > We found that one close-wait socket was reset by the other side
> > which is beyond our expectation,
>
> I'm unsure if you should instead reconsider your expectation: what if
> the client application does:
>
> shutdown(fd, SHUT_WR)
> close(fd); // with unread data

Thanks for the review.

Perhaps, I didn't clearly describe the details here. I'm not surprised
that the close-wait socket could be reset like you said. It's normal
behaviour. I'm surprised that the close-wait socket is reset by
another flow just because of the tw-reuse feature.

Can we reuse the port and then reset the previous connection which
stays in the close-wait state, I wonder?

Thanks,
Jason