From owner-freebsd-net@FreeBSD.ORG  Tue Jun 27 22:13:44 2006
Return-Path: <owner-freebsd-net@FreeBSD.ORG>
X-Original-To: net@freebsd.org
Delivered-To: freebsd-net@FreeBSD.ORG
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id 9604B16A40F
	for <net@freebsd.org>; Tue, 27 Jun 2006 22:13:44 +0000 (UTC)
	(envelope-from mi+mx@aldan.algebra.com)
Received: from aldan.algebra.com (aldan.algebra.com [216.254.65.224])
	by mx1.FreeBSD.org (Postfix) with ESMTP id 1652B45CEA
	for <net@freebsd.org>; Tue, 27 Jun 2006 22:13:43 +0000 (GMT)
	(envelope-from mi+mx@aldan.algebra.com)
Received: from corbulon.video-collage.com
	(static-151-204-231-237.bos.east.verizon.net [151.204.231.237])
	by aldan.algebra.com (8.13.6/8.13.6) with ESMTP id k5RMDf7W095473
	(version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK);
	Tue, 27 Jun 2006 18:13:42 -0400 (EDT)
	(envelope-from mi+mx@aldan.algebra.com)
Received: from [172.21.130.86] (mx-broadway [38.98.68.18])
	by corbulon.video-collage.com (8.13.6/8.13.6) with ESMTP id
	k5RMDZpc089916
	(version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO);
	Tue, 27 Jun 2006 18:13:36 -0400 (EDT)
	(envelope-from mi+mx@aldan.algebra.com)
From: Mikhail Teterin <mi+mx@aldan.algebra.com>
Organization: Virtual Estates, Inc.
To: net@freebsd.org
Date: Tue, 27 Jun 2006 18:13:29 -0400
User-Agent: KMail/1.9.1
MIME-Version: 1.0
Content-Type: text/plain;
  charset="us-ascii"
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
Message-Id: <200606271813.29980.mi+mx@aldan.algebra.com>
X-Virus-Scanned: ClamAV 0.88/1568/Tue Jun 27 14:39:17 2006 on
	corbulon.video-collage.com
X-Virus-Status: Clean
X-Scanned-By: MIMEDefang 2.43
Cc: rizzo@icir.org
Subject: using ipfw seems to interfere with socket communication
X-BeenThere: freebsd-net@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Networking and TCP/IP with FreeBSD <freebsd-net.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-net>,
	<mailto:freebsd-net-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-net>
List-Post: <mailto:freebsd-net@freebsd.org>
List-Help: <mailto:freebsd-net-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-net>,
	<mailto:freebsd-net-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 27 Jun 2006 22:13:44 -0000

After I added the following rules to my ipfw configuration:

	ipfw pipe 1 config bw 2000000000Mbit/s
	ipfw add 200 pipe 1 tcp from any to any

The following test from Tcl's regression-test suite started to fail:

    set s [socket -server accept 0]
    set sock ""
    set s2 [socket 127.0.0.1 [lindex [fconfigure $s -sockname] 2]]
    vwait sock
    puts $s2 "one"
    flush $s2
    after 500
    fconfigure $sock -blocking 0
    set result a:[gets $sock]
    lappend result b:[gets $sock]  
    fconfigure $sock -blocking 1
    puts $s2 "two"
    flush $s2
    fconfigure $sock -blocking 0
    lappend result c:[gets $sock]
    fconfigure $sock -blocking 1
    close $s2
    close $s
    close $sock
    set result

Instead of the expected ``a:one b: c:two'', the result was consistently 
``a:one b: c:''. This means, the gets in the line:

	lappend result c:[gets $sock]

was always returning empty string, instead of the string "two", that was 
written into the socket and flushed.

Is the test wrong, and such result is possible, or is dummynet triggering a 
bug? Unloading the dummynet module allows the test to succeed...

Thanks!

	-mi