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From:   Kuniyuki Iwashima <kuniyu@amazon.co.jp>
To:     <kafai@fb.com>
CC:     <andrii.nakryiko@gmail.com>, <andrii@kernel.org>, <ast@kernel.org>,
        <benh@amazon.com>, <bpf@vger.kernel.org>, <daniel@iogearbox.net>,
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        <kuni1840@gmail.com>, <kuniyu@amazon.co.jp>,
        <linux-kernel@vger.kernel.org>, <netdev@vger.kernel.org>
Subject: Re: [PATCH v5 bpf-next 00/11] Socket migration for SO_REUSEPORT.
Date:   Sat, 15 May 2021 12:48:21 +0900
Message-ID: <20210515034821.79264-1-kuniyu@amazon.co.jp>
In-Reply-To: <20210514062625.5zg626xquffvmrr7@kafai-mbp>
References: <20210514062625.5zg626xquffvmrr7@kafai-mbp>
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From:   Martin KaFai Lau <kafai@fb.com>
Date:   Thu, 13 May 2021 23:26:25 -0700
> On Fri, May 14, 2021 at 08:23:00AM +0900, Kuniyuki Iwashima wrote:
> > From:   Andrii Nakryiko <andrii.nakryiko@gmail.com>
> > Date:   Thu, 13 May 2021 14:27:13 -0700
> > > On Sun, May 9, 2021 at 8:45 PM Kuniyuki Iwashima <kuniyu@amazon.co.jp> wrote:
> > > >
> > > > The SO_REUSEPORT option allows sockets to listen on the same port and to
> > > > accept connections evenly. However, there is a defect in the current
> > > > implementation [1]. When a SYN packet is received, the connection is tied
> > > > to a listening socket. Accordingly, when the listener is closed, in-flight
> > > > requests during the three-way handshake and child sockets in the accept
> > > > queue are dropped even if other listeners on the same port could accept
> > > > such connections.
> > [...]
> > > 
> > > One test is failing in CI ([0]), please take a look.
> > > 
> > >   [0] https://travis-ci.com/github/kernel-patches/bpf/builds/225784969 
> > 
> > Thank you for checking.
> > 
> > The test needs to drop SYN+ACK and currently it is done by iptables or
                           ^^^^^^^
                           the final ACK of 3WHS
Sorry, this was typo.


> > ip6tables. But it seems that I should not use them. Should this be done
> > by XDP?
> or drop it at a bpf_prog@tc-egress.
> 
> I also don't have iptables in my kconfig and I had to add them
> to run this test.  None of the test_progs depends on iptables also.

I'll rewrite the dropping part with XDP or TC.
Thank you.


> 
> > 
> > ---8<---
> > iptables v1.8.5 (legacy): can't initialize iptables table `filter': Table does not exist (do you need to insmod?)
> > Perhaps iptables or your kernel needs to be upgraded.
> > ip6tables v1.8.5 (legacy): can't initialize ip6tables table `filter': Table does not exist (do you need to insmod?)
> > Perhaps ip6tables or your kernel needs to be upgraded.
> > ---8<---