From owner-freebsd-net@FreeBSD.ORG Mon Nov 7 10:04:37 2011 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 9B41C106566B for ; Mon, 7 Nov 2011 10:04:37 +0000 (UTC) (envelope-from przemyslaw@frasunek.com) Received: from lagoon.freebsd.lublin.pl (lagoon.freebsd.lublin.pl [IPv6:2a02:2928:a::3]) by mx1.freebsd.org (Postfix) with ESMTP id 22BC68FC0A for ; Mon, 7 Nov 2011 10:04:37 +0000 (UTC) Received: from [IPv6:2a02:2928:a:ffff:d179:25c5:30fe:e6e2] (unknown [IPv6:2a02:2928:a:ffff:d179:25c5:30fe:e6e2]) by lagoon.freebsd.lublin.pl (Postfix) with ESMTPSA id C66DE239453 for ; Mon, 7 Nov 2011 11:04:32 +0100 (CET) Message-ID: <4EB7AD2A.5050002@frasunek.com> Date: Mon, 07 Nov 2011 11:04:26 +0100 From: Przemyslaw Frasunek Organization: frasunek.com User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:7.0.1) Gecko/20110929 Thunderbird/7.0.1 MIME-Version: 1.0 To: freebsd-net@freebsd.org X-Enigmail-Version: 1.3.2 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: dummynet damages ICMPv6 packets X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 07 Nov 2011 10:04:37 -0000 Hello, we are experiencing interesing behaviour of dummynet enabled on IPv6 interfaces. When the following rules are added: add pipe 24 ip from any to any in recv vlan1 add pipe 25 ip from any to any out xmit vlan1 all ICMPv6 packets passing on vlan1 are being damaged: 10:55:53.180801 IP6 fe80::215:17ff:feae:4d99 > ff02::1: ip-proto-64 16 0x0000: 6000 0000 0010 403a fe80 0000 0000 0000 `.....@:........ 0x0010: 0215 17ff feae 4d99 ff02 0000 0000 0000 ......M......... 0x0020: 0000 0000 0000 0001 8000 2dc9 31f2 002e ..........-.1... 0x0030: 4eb7 ab29 0002 c207 N..).... Please note invalid protocol shown by tcpdump and shifted bytes at offset 7 and 8 (it reads 0x403a but should be 0x3a40). After changing dummynet rule to: add pipe 24 ip4 from any to any in recv vlan1 add pipe 25 ip4 from any to any out xmit vlan1 packets are no longer malformed: 11:01:49.934348 IP6 fe80::215:17ff:feae:4d99 > ff02::1: ICMP6, echo request, seq 0, length 16 0x0000: 6000 0000 0010 3a40 fe80 0000 0000 0000 `.....:@........ 0x0010: 0215 17ff feae 4d99 ff02 0000 0000 0000 ......M......... 0x0020: 0000 0000 0000 0001 8000 ab9a 3341 0000 ............3A.. 0x0030: 4eb7 ac8d 000e 41a5 N.....A. The above problem affects 8.2-STABLE compiled on 3rd May 2011.