From mboxrd@z Thu Jan  1 00:00:00 1970
From: martin zhang <martinbj2008@gmail.com>
Subject: A question about inet_csk_bind_conflict
Date: Fri, 30 Mar 2018 19:39:46 +0800
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To: davem@davemloft.net, Eric Dumazet <edumazet@google.com>
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HI all,

I have a question about tcp bind check function:inet_csk_bind_conflict.

My case:

192.168.56.101:37818    =3D=3D> 192.168.56.193:22
On host A (tcp client: 192.168.56.101), there is  a tcp connection to
server B(192.168.56.193, tcp server).

I want run a tcp server on A, and listen/bind tcp port 37818, but it failed=
.
I check the kernel source and found it is stopped by inet_csk_bind_conflict=
.

I think in this case, it should success.
Because,
1. when a tcp packet arrives network stack, we firstly look the
established/timewait socket,
and then search for listen socket.
2. peer side(192.168.56.193:22), is a tcp server. It will never
connect to192.168.56.101:37818, with 192.168.56.193:22.

I don=E2=80=99t  understand why the kernel fail at inet_csk_bind_conflict,
I wonder if I ignore some case or  it is a bug?

Thanks!

Martin