From owner-freebsd-stable@FreeBSD.ORG Mon Jul 12 17:03:06 2010 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id A4E721065672 for ; Mon, 12 Jul 2010 17:03:06 +0000 (UTC) (envelope-from antinix@gmail.com) Received: from mail-ww0-f50.google.com (mail-ww0-f50.google.com [74.125.82.50]) by mx1.freebsd.org (Postfix) with ESMTP id 3A7CA8FC0A for ; Mon, 12 Jul 2010 17:03:05 +0000 (UTC) Received: by wwb31 with SMTP id 31so237853wwb.31 for ; Mon, 12 Jul 2010 10:03:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:mime-version:sender:received :in-reply-to:references:from:date:x-google-sender-auth:message-id :subject:to:content-type; bh=zuikBW05b+iTX+1lMWQj9/L88sDMk21xdgw1TCV+PkY=; b=g+ZTPN5py2pIcmXjlAM/y9vFb3jp5oGWr4PttY2yK7LrgfspCAiSE1FjxsAOp5d8cz VPMnrn04pAIo/nqD+ODfZ9iCXsyVrYibaWnrthAVDzU0rRkKNfcWwAsgcID2FXPD8uUD 17JUUNmxdnFsDYqzWAL7t237hCyN4fdXeI4Pg= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:from:date :x-google-sender-auth:message-id:subject:to:content-type; b=JL85uoaas38sOVZmC3ave/ERcNpuTUKiGToehUe6NjiY+rtEu9JSdyFpRQTlM/EHRu fdkPIrJirDfacE9I4EeliYewe0oacFKZk1By9HdsiZiZWbK/urvHncvS/va0L/jm1M0K 8GXqeGmoLvf6z18sji4IHhEGwj9sNFk7x15gQ= Received: by 10.216.159.202 with SMTP id s52mr8883154wek.33.1278954184211; Mon, 12 Jul 2010 10:03:04 -0700 (PDT) MIME-Version: 1.0 Sender: antinix@gmail.com Received: by 10.216.45.194 with HTTP; Mon, 12 Jul 2010 10:02:44 -0700 (PDT) In-Reply-To: <20100712150147.542BE1CC0D@ptavv.es.net> References: <20100712150147.542BE1CC0D@ptavv.es.net> From: Andrei Kolu Date: Mon, 12 Jul 2010 20:02:44 +0300 X-Google-Sender-Auth: HxKXOz0QypAFQ256L89Qdyv8f5k Message-ID: To: freebsd-stable@freebsd.org Content-Type: text/plain; charset=ISO-8859-1 Subject: Re: bogus DSCP value for ssh X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 12 Jul 2010 17:03:06 -0000 2010/7/12 Kevin Oberman : >> From: Andrei Kolu >> Date: Mon, 12 Jul 2010 15:31:58 +0300 >> Sender: owner-freebsd-stable@freebsd.org >> >> Hi! >> >> I am testing FreeBSD 8.1-RC2 amd64 networking stuff and notice one >> strange DSCP message with wireshark: >> ------------------------------------ >> Internet Protocol, Src: 192.168.1.111 (192.168.1.111), Dst: >> 192.168.1.101 (192.168.1.101) >> Differentiated Services Field: 0x10 (DSCP 0x04: Unknown DSCP; ECN: 0x00) >> 0001 00.. = Differentiated Services Codepoint: Unknown (0x04) >> .... ..0. = ECN-Capable Transport (ECT): 0 >> .... ...0 = ECN-CE: 0 >> >> Transmission Control Protocol, Src Port: ssh (22), Dst Port: >> attachmate-s2s (2419), Seq: 2902917, Ack: 29842, Len: 132 >> ------------------------------------ >> >> There is no firewall enabled. Only thing I changed (should have no >> effect) was: "net.inet.tcp.ecn.enable: 1" >> _______________________________________________ > > I don't know why Wireshark does not understand this, but it is defined > in RFC2474 as Class Selector 2 or simply IP precedence of 2 (of 7). > > If you add the ECN bit, you have Assured Forwarding at IP priority 2. > > Whether you pass or respond to the DSCP bits is, of course, a personal > choice, but there is nothing unusual with this and ssh has bee setting > the bit for a long time. > -- My calculations (X is not used and always zero): 000|100|00 421|21X|00 ---------------- 000|200|00 11= high drop probability 10= medium drop probability 01= low drop probability So "Per-hop behavior" is 000binary= 0decimal and "Drop probability" is 10 binary=2 decimal="Medium drop probability". There is no such a DSCP drop probability value as 4 in existence. I think Wireshark is incorrect but how it is possible to define 000100 at all is beyound me- 000000 is "best effort" already. It is AF02? Yet another bogus priority value? Correct me if I'm wrong. Andrei