From: Eric Dumazet <eric.dumazet@gmail.com>
To: Alex Bergmann <alex@linlab.net>
Cc: davem@davemloft.net, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, Jerry Chu <hkchu@google.com>,
Neal Cardwell <ncardwell@google.com>,
Nandita Dukkipati <nanditad@google.com>
Subject: Re: [PATCH 1/1] tcp: Wrong timeout for SYN segments
Date: Wed, 22 Aug 2012 11:59:57 +0200 [thread overview]
Message-ID: <1345629597.5158.924.camel@edumazet-glaptop> (raw)
In-Reply-To: <5034A678.3040207@linlab.net>
On Wed, 2012-08-22 at 11:29 +0200, Alex Bergmann wrote:
> Actual 6 SYN frames are sent. The initial one and 5 retries.
>
first one had a t0 + 0 delay. How can it count ???
> The kernel is waiting another 32 seconds for a SYN+ACK and then gives
> the ETIMEDOUT back to userspace.
>
> Do you mean that we have to send another SYN packet after the 3 minutes?
>
First SYN is not a retransmit
R2 = time_of_last_SYN - time_of_initial_SYN (t0) = 31
If you read RFC it states :
"In particular, R2 for a SYN segment MUST
be set large enough to provide retransmission of the segment
for at least 3 minutes."
That means that the last _retransmit_ MUST happen after 180 seconds.
And not :
Send all the restransmits at t0 + 1, then wait 180 seconds before giving
connect() a timeout indication.
next prev parent reply other threads:[~2012-08-22 10:00 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-21 23:29 [PATCH 1/1] tcp: Wrong timeout for SYN segments Alex Bergmann
2012-08-22 8:06 ` Eric Dumazet
2012-08-22 8:48 ` Alex Bergmann
2012-08-22 8:58 ` Eric Dumazet
2012-08-22 9:29 ` Alex Bergmann
2012-08-22 9:59 ` Eric Dumazet [this message]
2012-08-22 10:03 ` Eric Dumazet
2012-08-22 17:29 ` H.K. Jerry Chu
2012-08-22 16:44 ` H.K. Jerry Chu
[not found] ` <CAFbMe2M7ekc94bQk7vTS1LhScPd49VZ-zKOCUXhqwxXtL-nkuA@mail.gmail.com>
2012-08-23 11:58 ` Alex Bergmann
2012-08-23 12:15 ` Eric Dumazet
2012-08-23 12:35 ` David Laight
2012-08-23 12:51 ` Eric Dumazet
2012-08-23 12:37 ` Alex Bergmann
2012-08-23 12:49 ` Eric Dumazet
2012-08-24 12:17 ` Alex Bergmann
2012-08-24 17:42 ` David Miller
2012-08-25 8:48 ` Alexander Bergmann
2012-08-25 9:01 ` Eric Dumazet
2012-08-28 8:44 ` Carsten Wolff
[not found] ` <1346414260.2591.8.camel@edumazet-glaptop>
2012-08-31 12:48 ` Alexander Bergmann
2012-08-31 13:25 ` Eric Dumazet
2012-08-31 19:42 ` David Miller
2012-08-31 19:47 ` David Miller
2012-08-29 4:34 ` H.K. Jerry Chu
2012-08-29 8:51 ` Eric Dumazet
2012-08-29 17:25 ` H.K. Jerry Chu
2012-08-30 13:12 ` Eric Dumazet
2012-08-30 16:45 ` David Miller
2012-08-30 18:04 ` H.K. Jerry Chu
2012-08-30 17:59 ` H.K. Jerry Chu
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