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Date:      Thu, 13 Dec 2001 16:53:07 -0600 (CST)
From:      mark tinguely <tinguely@web.cs.ndsu.nodak.edu>
To:        freebsd-net@freebsd.org
Subject:   TCP snd_recover
Message-ID:  <200112132253.fBDMr7S42070@web.cs.ndsu.nodak.edu>

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I am playing with RFC 3042 and notice some strange dupacks count sequences.
One place I see a problem is with snd_recover and newreno:

		if (tcp_do_newreno && SEQ_LT(th->th_ack,
		    tp->snd_recover)) {

if th->th_ack > 0x7fffffff and snd_recover has not been initialized,
the problem results in a ACK loop that continues until a rexmt timer
expires, and a side effect of timer, the snd_recover is finally set.

from looking things over, this could happen from wrapping sequences
also since we do not check if snd_una <= snd_recover <= snd_max,
but less likely. I have not caught this in a trace yet.

--mark tinguely.

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