From owner-freebsd-net@freebsd.org Wed Sep 5 05:46:51 2018 Return-Path: Delivered-To: freebsd-net@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 97C73FE45E9 for ; Wed, 5 Sep 2018 05:46:51 +0000 (UTC) (envelope-from james.blachly@gmail.com) Received: from mail-it0-x230.google.com (mail-it0-x230.google.com [IPv6:2607:f8b0:4001:c0b::230]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 26DF0726EC for ; Wed, 5 Sep 2018 05:46:51 +0000 (UTC) (envelope-from james.blachly@gmail.com) Received: by mail-it0-x230.google.com with SMTP id p79-v6so8336022itp.3 for ; Tue, 04 Sep 2018 22:46:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:content-transfer-encoding:mime-version:subject:message-id:date :to; bh=DEl22AHM0fCsFuWETROzcYa272nKElcsAHj+68/kVI8=; b=NjCO9F4I+qWh54bRN+bC8MK+o8EFHenaiKJyeTPlG+EP5/ZlNaFBYk+8T23mCl1g3Y 1l7wP7KN3KKVYC3Xu+5g9WITU9qpP5bdpEXFfiGlRlIrgp642CEr0+DyJ4ZYSUfhm4G2 DqIyApDGQo3NKoWJ2cN2dNFjvZ0rB2qnJYXYs4fcSOLRT8OPHVrxq6DwnblDnLYS2yoo xgt2MLNZlheIaXt40csQImwGHFZctXNODCOMcsFx3AGB8Q+lIev2N+zOOK5jYVePPDnF sLCvgmmyr4MJYDd48fEkNF4+19UU9c2Y8n/rrWnNVbPR+0tN4wNK91DARVoucypPuwxr lxcw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:content-transfer-encoding:mime-version :subject:message-id:date:to; bh=DEl22AHM0fCsFuWETROzcYa272nKElcsAHj+68/kVI8=; b=cp03M1xSlLHcuHLTzlskM5XJlISED4N9b+dFYIB8WQJ7GHZtv29vYddBYx0RHC6Nhm 0M+SmUc3o0CLtr7ZlcaVodDC77ysOQ7eE9vS9hvxUmK3lVwjvrX1Td2BeafDq6o0Jtsf 4G/i/brIjcUcSpGsqmChLS5zoVrnwwp0BHFaMWzNIA5GVwbVxAQyVTzjTEVViN1UxNwV pw2QvEvOinCuMIviO/4bd1tvSQDRNH6cFL8KutQ8qJJ8lnb1Fp9aw4l/MIchSPqsO1xP UzLg9JBTfvqjkPfdIQXqddcIwOAaa9foEprQhXzPdN2Kheh/mUOlWvpBuqti+lOucgt4 ee7w== X-Gm-Message-State: APzg51BDSP67iuFrdL5U0dF9rMV67ejL6vdz7ZpyIWncrfgxmgnuGhSi CORDJfqTZA704Jrz5UYcyQiJZNYf X-Google-Smtp-Source: ANB0VdZJQQXJwVdbUxmtxB9MXLJzOWS7Thd4IEcZHGm8krIy73Ez1+PCflhmgKrazz/ZAtNB7NL7iQ== X-Received: by 2002:a24:d9d6:: with SMTP id p205-v6mr2744278itg.89.1536126410305; Tue, 04 Sep 2018 22:46:50 -0700 (PDT) Received: from [192.168.1.40] ([67.149.75.249]) by smtp.gmail.com with ESMTPSA id 84-v6sm547939ita.35.2018.09.04.22.46.49 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 04 Sep 2018 22:46:49 -0700 (PDT) From: James Blachly Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Mime-Version: 1.0 (Mac OS X Mail 11.3 \(3445.6.18\)) Subject: multicast packets not seen on PHY bridge member Message-Id: <5F7908EB-0240-476F-9EED-5EEBFA5547C4@gmail.com> Date: Wed, 5 Sep 2018 01:46:48 -0400 To: freebsd-net@freebsd.org X-Mailer: Apple Mail (2.3445.6.18) X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.27 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 05 Sep 2018 05:46:51 -0000 I am new to FreeBSD so please forgive (and correct) wrong terminology = and concepts. I=E2=80=99ve installed FreeBSD 11.2 as a VM host and run in to a problem = with multicast packets over a bridge not being seen by programs [on the = host] listening on the bridge=E2=80=99s physical interface constituent = (igb1), which I discovered when running avahi-daemon. Briefly, my setup is as follows: FreeBSD 11.2 host, bare metal, eth PHY igb1 bridge0 with members igb1, tap0, tap1 VM linux guest virtio-net to tap0 to bridge on FreeBSD VM freebsd guest virtio-net to tap1 to bridge on FreeBSD=20 Mac, 802.11 to AP to same switch as FreeBSD mDNS query/response operates properly between the mac and any of the = others (both physical and virtual), and all work in the converse = direction with the mac. The guests, all of which are constituents of = the bridge, are able to communicate via mDNS with one another. However, = the guests are _unable_ to communicate with the host via mDNS. tcpdump = shows the query packets appearing on igb1, but truss on avahi-daemon = shows they are not received. This means multicast packets are forwarded out all members of the = bridge, but not IN (at least, to physical interfaces =E2=80=94 they do = seem to go both directions on the taps) If I add an IP address to the bridge, avahi-daemon on the host binds to = the bridge interface directly and then receives incoming packets, = responding with the IP of the bridge. All then operates correctly, = except that the host now has two IPs on the same subnet of course. My question is: given that if_bridge(4) is described as a virtual = switch: A bridge works like a switch, forwarding traffic from one interface = to another. Multicast and broadcast packets are always forwarded to = all interfaces that are part of the bridge. For unicast traffic, the = bridge learns which MAC addresses are associated with which interfaces and = will forward the traffic selectively. and given that unicast packets originating on one of the bridge=E2=80=99s = taps are received by host programs bound to igb1, it seems to me that = anything bound to igb1 should also be receiving the multicast packets.=20= Is this an error specifically related to multicast and bridging, or is = it an accident that unicast connections work? (or, none of the above) Kind regards and thanks in advance. jsb