From: Florian Westphal <fw@strlen.de>
To: David Miller <davem@davemloft.net>
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 23:57:26 +0100 [thread overview]
Message-ID: <20170315225726.GA28498@breakpoint.cc> (raw)
In-Reply-To: <20170315.154044.170788541865531834.davem@davemloft.net>
David Miller <davem@davemloft.net> 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.
Sigh.
"don't enable this if you connect your machine to the internet".
We're not in the 1990s anymore. Even I am behind ipv4 CG-NAT nowadays.
So I disagree and would remove this thing.
> 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.
AFAIU we only have two alternatives, removal of the randomization feature
or switch to a offset computed via hash(saddr, daddr, secret).
Unless there are more comments I'll look into doing the latter tomorrow.
next prev parent reply other threads:[~2017-03-15 22:57 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 [this message]
2017-03-15 23:45 ` David Miller
2017-03-15 22:59 ` Eric Dumazet
2017-03-15 23:45 ` David Miller
2017-03-16 0:06 ` Eric Dumazet
2017-03-19 7:53 ` Alexander Alemayhu
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