netdev - Re: TCP_DEFER_ACCEPT brokenness?

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Message-ID: <Pine.LNX.4.58.0701310011450.2627@u.domain.uli>
Date:	Wed, 31 Jan 2007 00:28:16 +0200 (EET)
From:	Julian Anastasov <ja@....bg>
To:	dean gaudet <dean@...tic.org>
cc:	netdev@...r.kernel.org, mtk-manpages@....net
Subject: Re: TCP_DEFER_ACCEPT brokenness?


	Hello,

On Tue, 30 Jan 2007, dean gaudet wrote:

> > which is a bit confusing because it talks both about seconds and
> > "attempts".  (and doesn't mention what happens when the timeout finishes
> > -- i could see dropping the socket or passing it to userland anyhow as
> > possibilities... but in fact the socket is dropped).

	My understanding about SYN-ACKs is:

- there is always one SYN+ACK and at least one retransmission (min 
3+6 secs period to accept ACK)

- TCP_SYNCNT (or tcp_synack_retries) define the number of retransmissions,
this is a minimum that TCP_DEFER_ACCEPT can not reduce (due to the
'req->retrans < thresh' check). It can only extend it after the
ACK is received.

- TCP_DEFER_ACCEPT defines seconds (total time) to wait for ACK
plus first data

	Hint: one option is that you can treat TCP_DEFER_ACCEPT as flag, 
set it to 1 and then tune TCP_SYNCNT to cover the max desired period to 
wait for data.

Regards

--
Julian Anastasov <ja@....bg>
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