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From:   Yafang Shao <laoar.shao@gmail.com>
Date:   Wed, 13 Feb 2019 10:46:59 +0800
Message-ID: <CALOAHbCLR-Eyr=7fFmU=_gRN-7HPiOdbFYbNNK_xNqmPFYFfOw@mail.gmail.com>
Subject: Re: [bpf-next 1/2] tcp: replace SOCK_DEBUG() with tcp_stats()
To:     Eric Dumazet <edumazet@google.com>
Cc:     Eric Dumazet <eric.dumazet@gmail.com>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Alexei Starovoitov <ast@kernel.org>,
        Yonghong Song <yhs@fb.com>, Lawrence Brakmo <brakmo@fb.com>,
        David Miller <davem@davemloft.net>,
        netdev <netdev@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>, shaoyafang@didiglobal.com
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On Wed, Feb 13, 2019 at 10:15 AM Eric Dumazet <edumazet@google.com> wrote:
>
> On Tue, Feb 12, 2019 at 6:07 PM Yafang Shao <laoar.shao@gmail.com> wrote:
> >
>
> > Let me explain the background for you.
> > I want to track some TCP abnormal  behavior in TCP/IP stack. But I
> > find there's no good way to do it.
> > The current MIBs are per net, other than per socket, that makes it not
> > very powerful.
> > And the ancient SOCK_DEBUG is not good as well.
> > So we think why not cleanup this ancient SOCK_DEBUG() and introduce a
> > more powerful method.
>
>
> I am all for it, but this more powerful method does nothing at all in
> the current patches.
>
> I can not accept patches just because they seem to be harmless,
> knowing that  the next patches
> will be pushed later changing more stuff, just because the new
> infrastructure is there "and can be used"
>
> Just remove all SOCK_DEBUG() calls, there are leftovers of very ancient times.
>

OK. I will send a patch for it.

> Do not add more debugging stuff unless you can demonstrate
> they actually allowed you to find a real bug and that you sent a
> public fix for it.
>

Sure.

> Just adding "cool stuff" in TCP stack does not please me, it is only
> more complexity for unproven gain.
>
> Otherwise, I am tempted to think that these BPF hooks are there only
> so that a company can more
> easily build a private variant of TCP, yet letting the community
> maintaining the hard part of TCP stack.

:-)

>
> Thank you.


Thanks
Yafang