From: Eric Dumazet <eric.dumazet@gmail.com>
To: Rick Jones <rick.jones2@hp.com>
Cc: "David Miller" <davem@davemloft.net>,
netdev <netdev@vger.kernel.org>,
"Perry Lorier" <perryl@google.com>,
"Matt Mathis" <mattmathis@google.com>,
"Yuchung Cheng" <ycheng@google.com>,
"Neal Cardwell" <ncardwell@google.com>,
"Tom Herbert" <therbert@google.com>,
"Wilmer van der Gaast" <wilmer@google.com>,
"Dave Täht" <dave.taht@bufferbloat.net>,
"Ankur Jain" <jankur@google.com>
Subject: Re: [PATCH net-next] tcp: be more strict before accepting ECN negociation
Date: Fri, 04 May 2012 21:05:59 +0200 [thread overview]
Message-ID: <1336158359.3752.382.camel@edumazet-glaptop> (raw)
In-Reply-To: <4FA42491.2020104@hp.com>
On Fri, 2012-05-04 at 11:48 -0700, Rick Jones wrote:
> On 05/04/2012 11:23 AM, Eric Dumazet wrote:
> > On Fri, 2012-05-04 at 11:09 -0700, Rick Jones wrote:
> >> What sort of networks were these? Any chance it was some sort of
> >> attempt to add ECN to FastOpen?
> >
> > Nothing to do with fastopen.
> >
> > Just take a look at a random http server and sample all SYN packets it
> > receives.
> >
> > Some of them have TOS bits 0 or 1 set, or even both bits set.
>
> I'll fire-up tcpdump on netperf.org:
>
> tcpdump -i eth0 -vvv '(tcp[tcpflags] & tcp-syn != 0) && (ip[1] != 0x0)'
>
> and see what appears.
>
> rick
of (ip[1] & 3 != 0)
Note that you could catch SYNACK with this filter (if your machine
initiates some active TCP sessions), since SYNACK might have ECT bits,
if some stacks implemented :
http://tools.ietf.org/html/draft-kuzmanovic-ecn-syn-00 ( Adding
Explicit Congestion Notification (ECN) Capability to TCP's SYN/ACK
Packets )
http://tools.ietf.org/id/draft-ietf-tcpm-ecnsyn-04.txt
next prev parent reply other threads:[~2012-05-04 19:06 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-04 15:14 [PATCH net-next] tcp: be more strict before accepting ECN negociation Eric Dumazet
2012-05-04 15:54 ` Neal Cardwell
2012-05-04 16:06 ` David Miller
2012-05-04 18:09 ` Rick Jones
2012-05-04 18:23 ` Eric Dumazet
2012-05-04 18:48 ` Rick Jones
2012-05-04 19:05 ` Eric Dumazet [this message]
2012-05-04 20:20 ` Rick Jones
2012-05-04 20:36 ` Rick Jones
2012-05-04 20:49 ` Eric Dumazet
2012-05-04 21:01 ` Rick Jones
2012-05-04 21:14 ` Eric Dumazet
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