From owner-freebsd-net@freebsd.org Thu Jan 14 01:59:41 2021 Return-Path: Delivered-To: freebsd-net@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 0C66F4D0568 for ; Thu, 14 Jan 2021 01:59:41 +0000 (UTC) (envelope-from jmg@gold.funkthat.com) Received: from gold.funkthat.com (gate2.funkthat.com [208.87.223.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "gate2.funkthat.com", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4DGSDX1NMPz4b0q for ; Thu, 14 Jan 2021 01:59:39 +0000 (UTC) (envelope-from jmg@gold.funkthat.com) Received: from gold.funkthat.com (localhost [127.0.0.1]) by gold.funkthat.com (8.15.2/8.15.2) with ESMTPS id 10E1xLfF013673 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Wed, 13 Jan 2021 17:59:21 -0800 (PST) (envelope-from jmg@gold.funkthat.com) Received: (from jmg@localhost) by gold.funkthat.com (8.15.2/8.15.2/Submit) id 10E1xH9H013671; Wed, 13 Jan 2021 17:59:17 -0800 (PST) (envelope-from jmg) Date: Wed, 13 Jan 2021 17:59:17 -0800 From: John-Mark Gurney To: "Andrey V. Elsukov" Cc: Lutz Donnerhacke , freebsd-net@freebsd.org, Hans Petter Selasky Subject: Re: FreeBSD does not reply to IPv6 Neighbor Solicitations Message-ID: <20210114015917.GR31099@funkthat.com> Mail-Followup-To: "Andrey V. 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Elsukov wrote this message on Wed, Jan 13, 2021 at 11:42 +0300: > On 13.01.2021 00:37, John-Mark Gurney wrote: > >> when this will happen again, it would be nice to make sure that NS > >> packets hit the IP stack. E.g. with attached dtrace script. > > > > Ok, I ran the dtrace script when I reproduced the problem, and it did > > not produce any output. > > > > These are effectively what the script does: > > 9) configure inet6 addresses on ure and bge (duplicating the addresses > > already configured) > > Does it mean that you just reconfigure address without removing it? It > looks like the problem, that was discussed here > https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=233535 Yeah, I guess it is the same... > > bge0: > > inet6 fe80::12e7:c6ff:fexx:xxxx%bge0 scopeid 0x2 > > mldv2 flags=2 rv 2 qi 125 qri 10 uri 3 > > group ff01::1%bge0 scopeid 0x2 mode exclude > > mcast-macaddr 33:33:00:00:00:01 > > group ff02::1%bge0 scopeid 0x2 mode exclude > > mcast-macaddr 33:33:00:00:00:01 > > group ff02::1:ffxx:xxxx%bge0 scopeid 0x2 mode exclude > > mcast-macaddr 33:33:ff:xx:xx:xx > > > > so, I made things works, and ran ifmcstat again, and this time it has > > an additional group in the output: > > [...] > > bge0: > > inet6 fe80::12e7:c6ff:fexx:xxxx%bge0 scopeid 0x2 > > mldv2 flags=2 rv 2 qi 125 qri 10 uri 3 > > group ff02::1:ff00:c43c%bge0 scopeid 0x2 mode exclude > > mcast-macaddr 33:33:ff:00:c4:3c > > group ff01::1%bge0 scopeid 0x2 mode exclude > > mcast-macaddr 33:33:00:00:00:01 > > group ff02::1%bge0 scopeid 0x2 mode exclude > > mcast-macaddr 33:33:00:00:00:01 > > group ff02::1:ffxx:xxxx%bge0 scopeid 0x2 mode exclude > > mcast-macaddr 33:33:ff:xx:xx:xx > > > > and the tcpdump output: > > 21:10:53.938655 IP6 fc00:b5d:41c:7e37::7e37 > ff02::1:ff00:c43c: ICMP6, neighbor solicitation, who has fc00:b5d:41c:7e37::c43c, length 32 > > 21:10:55.001428 IP6 fc00:b5d:41c:7e37::7e37 > ff02::1:ff00:c43c: ICMP6, neighbor solicitation, who has fc00:b5d:41c:7e37::c43c, length 32 > > Since ff02::1:ff00:c43c%bge0 is not configured in first case, IP stack > just ignores NS messages and they don't hit ND6 code. > > In the PR 233535 the problem was reproducible with MLDv1, so if you > disable MLDv2 will it work (to reduce possible scope of problematic code)? > > net.inet6.mld.v2enable=0 I just tested this, and it does not fix the problem for me. Do I need to reboot or something? If I set it to 0, the bug still appears, and also the ifmcstat has the line: mldv2 flags=2 rv 2 qi 125 qri 10 uri 3 is there something else that needs to be done to disable mldv2? -- John-Mark Gurney Voice: +1 415 225 5579 "All that I will do, has been done, All that I have, has not."