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Date: Sun, 15 Jul 2012 08:47:34 -0700
From: Reese Faucette <reese@myri.com>
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Cc: freebsd-net@freebsd.org
Subject: Re: question in tcp_do_segment()
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On 7/15/2012 3:26 AM, Sepherosa Ziehau wrote:

> !tcp_timer_active() means that the connection's retransmit timer is
> not _set_ yet (please note, it is _not_ "has fired").  As far as I
> understand this code, it in turn means that this connection doesn't
> have any segments that were sent but not yet ACKed.

You'd think that was the case from the name, but tcp_timer_active() 
calls callout_active() which checks for fired.  If you want to check for 
"timer set" you need to use callout_pending().
-reese