Skip site navigation (1)Skip section navigation (2)
Date:      Mon, 19 Jan 2004 01:21:01 -0600 (CST)
From:      Mike Silbersack <silby@silby.com>
To:        rw@codeburst.co.uk
Cc:        freebsd-net@freebsd.org
Subject:   Re: forged tsecr giving -ve numbers in rtt calculation causing retran
Message-ID:  <20040119011745.D85911@odysseus.silby.com>
In-Reply-To: <200401162336.XAA04091@starburst.demon.co.uk>
References:  <200401162336.XAA04091@starburst.demon.co.uk>

next in thread | previous in thread | raw e-mail | index | archive | help

On Fri, 16 Jan 2004, Richard Wendland wrote:

> I'd hazard a guess that you are seeing zero, not forged, TSECRs.
> Windows sets TSECR zero on SYN-ACK when it does a passive open.  This is
> established Windows behaviour for several years, and there is a reading
> of RFC1323 that might justify this.

Hm, wasn't this accounted for in rev 1.174 / 1.107.2.31?  From Matt's
commit log:

---
...
FreeBSD sends a
timestamp with the SYN, W2K returns a timestamp of 0 in the SYN+ACK
causing FreeBSD to calculate an insane SRTT and RTT, resulting in
a maximal retransmit timeout (60 seconds).
...
This commit works around the W2K bug.
---

Of course, that doesn't account for other non-zero strange values.  I
guess the timestamp code needs a lot of work. :(

Mike "Silby" Silbersack



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20040119011745.D85911>