From nobody Wed Apr 08 15:39:27 2026 X-Original-To: net@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4frS106KCsz6YKCc for ; Wed, 08 Apr 2026 15:39:32 +0000 (UTC) (envelope-from ivy@freebsd.org) Received: from smtp.freebsd.org (smtp.freebsd.org [96.47.72.83]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "smtp.freebsd.org", Issuer "R13" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 4frS105CFpz45Lk for ; Wed, 08 Apr 2026 15:39:32 +0000 (UTC) (envelope-from ivy@freebsd.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1775662772; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=RRBChFTiBCjQTQhkb5vuFC5Tu4t2b1MY1M2NHD0ASb8=; b=X5RXH+BeKiu9mO66pdvbTFXswMCoYIF6Sdy8kiYKSpTh/LoM7JEtFAiENZ8GPHs/mC//HW TszCgkvdjj7IaKdmrjuBUX9bQuBAwgOiXREkPX9ghlJg1lUTOypM7wmz1q92v+l2CxbOIG PnVbu5HDaOnePyRTDaNACWRh1TXXET73fzF+1OKVx6jcd/tt2H7vOZpsFQ483aWQK65mg4 amYULRhUp8WbYKtBNo2GExzp1n/9ksRnvbyyFrsxGR+YMBS+CxRyjvSLwJ6Fz49n8R76DR N2koSVQLAOd8nxxSoqqybvXMqxCG8N9jrZBWmjTwJTUNFChrjihfXQK4Rs4+uA== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1775662772; a=rsa-sha256; cv=none; b=FLbT6MYJ3Mor3HTRbwbEquJFH/8b+cnOl66YkrK7vVY4nUX1qBDlmo82gepD7dp3L2Q+S3 UdalZJjWyPj61sKkj2Yny9xOkPbfIb8Jd3C5nCbUdlzrPFGFMpai3djGGx/k7bc+jJ3ZbC uXiFdTSNhTDv8vJeC1uVV5c06pHmr5rElJQIPeBq+SSvTNeZ6SjzZUXahKpsBQC9aR4eHw 4cS1qp5XB1VoBr/Fd7dfYQ7nXPalO4b8n8ZQib2mcQh/khsmeueTlCZmbcRyX66Yl2L+31 Z0yll7GVKK0ySKVazMiSYL/g/3/lv5keNbSwIcmOsoDS+hghDSJFGPJS/mfc9Q== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1775662772; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=RRBChFTiBCjQTQhkb5vuFC5Tu4t2b1MY1M2NHD0ASb8=; b=lWzx/NXP5ltI4Bip51YZyImPSar3KHZsEdpXsYBtjNsvCbkbgeUXgIGh1vU4Z/wxqB9Lw5 PtDvE7tJTyKqxcNjkbcTy6ATx/EXqVYG14C3QZCxOgBpNQl+OpYlx3RNakTJ+Be5wrHpGY nsnD4ZGJJqYJMO56Jfe+PMJi5a4f9ye7UQU7v5UyH225YEc+Afod0tTWggl8oI0kWjW5YX YyEOBea2XNKx/jdB2XLJkisJBcrXl7ipNBzu57Hs8OzcAUahnPItr1N5XTX7NkmeVWDSOb 51R3RWChDMQIzLLEEHOp5dOsaMmOlBwaS5XCeRLN610Tq5O9lONUtzz3726u9g== Received: from amaryllis.le-fay.org (amaryllis.le-fay.org [IPv6:2a00:1098:6b:400::9]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) (Authenticated sender: ivy/mail) by smtp.freebsd.org (Postfix) with ESMTPSA id 4frS1022tkz30G for ; Wed, 08 Apr 2026 15:39:32 +0000 (UTC) (envelope-from ivy@freebsd.org) Date: Wed, 8 Apr 2026 16:39:27 +0100 From: Lexi Winter To: net@freebsd.org Subject: Re: FreeBSD guest on Linux KVM, some vtnet(4) packets don't arrive Message-ID: Mail-Followup-To: net@freebsd.org References: <28495B68-0BD1-4372-806C-C766DBCB8410@FreeBSD.org> List-Id: Networking and TCP/IP with FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-net List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-net@FreeBSD.org MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="yFpjVRScZsmC9w5k" Content-Disposition: inline In-Reply-To: <28495B68-0BD1-4372-806C-C766DBCB8410@FreeBSD.org> --yFpjVRScZsmC9w5k Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Zhenlei Huang wrote in <28495B68-0BD1-4372-806C-C766DBCB8410@FreeBSD.org>: > > a route exists for this on the host: > >=20 > > fd00:0:0:1::b via fe80::2 dev vm-ppc64-main proto bird metric 32 pref m= edium >=20 > Just to confirm, do you have a reverse route on the guest ? no, in fact, this was the problem. after adding a default route on the guest side: # route add -inet6 default fe80::1%vtnet0 =2E.. now everything is working fine. thanks! but i failed to notice that problem because of the tcpdump issue, which is still present... > That puzzled me a bit. If the net stack sees the arriving packets, then t= cpdump shall > intercept them correctly. even with the network working, tcpdump is still not showing any packets. i have no idea what's going on here or even where to start looking. i'm currently installing a ppc64le guest on the same host to see if that behaves any differently. > Does `netstat -sp ip6` and `netstat -sp icmp6` show anything unusual ? root@ppc64-main:~ # netstat -sp ip6 ip6: 18 total packets received 0 with size smaller than minimum 0 with data size < data length 0 with bad options 0 with incorrect version number 0 fragments received 0 fragments dropped (dup or out of space) 0 fragments dropped after timeout 0 fragments that exceeded limit 0 atomic fragments 0 packets reassembled ok 15 packets for this host 0 packets forwarded 0 packets not forwardable 0 redirects sent 20 packets sent from this host 0 packets sent with fabricated ip header 0 output packets dropped due to no bufs, etc. 0 output packets discarded due to no route 0 output datagrams fragmented 0 fragments created 0 datagrams that can't be fragmented 0 packets that violated scope rules 0 multicast packets which we don't join Input histogram: hop by hop: 18 Mbuf statistics: 0 one mbuf 18 one ext mbuf 0 two or more ext mbuf 0 packets whose headers are not contiguous 0 tunneling packets that can't find gif 0 packets discarded because of too many headers 0 failures of source address selection source addresses on an outgoing I/F 4 addresses scope=3D0 source addresses on a non-outgoing I/F 3 addresses scope=3D0 source addresses of same scope 3 addresses scope=3D0 source addresses of a different scope 4 addresses scope=3D0 Source addresses selection rule applied: 10 first candidate t@ppc64-main:~ # netstat -sp icmp6 icmp6: 0 calls to icmp6_error 0 errors not generated in response to an icmp6 message 0 errors not generated because of rate limitation Output histogram: echo: 8 neighbor solicitation: 2 neighbor advertisement: 2 MLDv2 listener report: 2 0 messages with bad code fields 0 messages < minimum length 0 bad checksums 0 messages with bad length 0 total packets dropped due to failed NDP resolution Input histogram: unreach: 3 time exceed: 3 echo reply: 8 neighbor solicitation: 2 neighbor advertisement: 2 Histogram of error messages to be generated: 0 no route 0 administratively prohibited 0 beyond scope 0 address unreachable 0 port unreachable 0 packet too big 0 time exceed transit 0 time exceed reassembly 0 erroneous header field 0 unrecognized next header 0 unrecognized option 0 redirect 0 unknown 0 message responses generated 0 messages with too many ND options 0 messages with bad ND options 0 bad neighbor solicitation messages 0 bad neighbor advertisement messages 0 bad router solicitation messages 0 bad router advertisement messages 0 bad redirect messages 0 default routers overflows 0 prefix overflows 0 neighbour entries overflows 0 redirect overflows 0 messages with invalid hop limit 0 path MTU changes --yFpjVRScZsmC9w5k Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQSyjTg96lp3RifySyn1nT63mIK/YAUCadZ2rAAKCRD1nT63mIK/ YAK8AP9le+Mm1iNhZrcCM/YJqzQlRFlY+d/o5urBfgw13W1ruQEAh3t38b0EDChE KuFslCJpfcq1bwpXJD80AOvPsCse6AA= =hEG6 -----END PGP SIGNATURE----- --yFpjVRScZsmC9w5k--