From: David Miller <davem@davemloft•net>
To: eric.dumazet@gmail•com
Cc: soheil.kdev@gmail•com, netdev@vger•kernel.org, soheil@google•com,
edumazet@google•com, ncardwell@google•com, ycheng@google•com,
lvml@5t9•de, fw@strlen•de
Subject: Re: [PATCH net-next 1/2] tcp: remove per-destination timestamp cache
Date: Wed, 15 Mar 2017 16:45:08 -0700 (PDT) [thread overview]
Message-ID: <20170315.164508.1392215340407263261.davem@davemloft.net> (raw)
In-Reply-To: <1489618741.28631.172.camel@edumazet-glaptop3.roam.corp.google.com>
From: Eric Dumazet <eric.dumazet@gmail•com>
Date: Wed, 15 Mar 2017 15:59:01 -0700
> On Wed, 2017-03-15 at 15:40 -0700, David Miller wrote:
>> From: Soheil Hassas Yeganeh <soheil.kdev@gmail•com>
>> Date: Wed, 15 Mar 2017 16:30:45 -0400
>>
>> > Note that this cache was already broken for caching timestamps of
>> > multiple machines behind a NAT sharing the same address.
>>
>> That's the documented, well established, limitation of time-wait
>> recycling.
>>
>> People who enable it, need to consider this issue.
>>
>> This limitation of the feature does not give us a reason to break the
>> feature even further as a matter of convenience, or to remove it
>> altogether for the same reason.
>>
>> Please, instead, fix the bug that was introduced.
>>
>> Thank you.
>
> You mean revert Florian nice patches ?
>
> This would kill timestamps randomization, and thus prevent some
> organizations to turn TCP timestamps on.
>
> TCP timestamps are more useful than this obscure tw_recycle thing that
> is hurting innocent users.
Ok, I guess we can remove it in that case. I'm still a bit disappointed
as I was always hoping someone would find a way to make this work even
in the presence of NAT.
I must be too optimistic.
next prev parent reply other threads:[~2017-03-15 23:46 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-15 20:30 [PATCH net-next 1/2] tcp: remove per-destination timestamp cache Soheil Hassas Yeganeh
2017-03-15 20:30 ` [PATCH net-next 2/2] tcp: remove tcp_tw_recycle Soheil Hassas Yeganeh
2017-03-15 22:40 ` [PATCH net-next 1/2] tcp: remove per-destination timestamp cache David Miller
2017-03-15 22:55 ` Willy Tarreau
2017-03-16 11:31 ` Lutz Vieweg
2017-03-16 15:40 ` Neal Cardwell
2017-03-16 16:05 ` Willy Tarreau
2017-03-16 17:30 ` Lutz Vieweg
2017-03-15 22:57 ` Florian Westphal
2017-03-15 23:45 ` David Miller
2017-03-15 22:59 ` Eric Dumazet
2017-03-15 23:45 ` David Miller [this message]
2017-03-16 0:06 ` Eric Dumazet
2017-03-19 7:53 ` Alexander Alemayhu
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