From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: passt.top; dmarc=none (p=none dis=none) header.from=gibson.dropbear.id.au Authentication-Results: passt.top; dkim=pass (2048-bit key; secure) header.d=gibson.dropbear.id.au header.i=@gibson.dropbear.id.au header.a=rsa-sha256 header.s=202510 header.b=oSwMQJWs; dkim-atps=neutral Received: from mail.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by passt.top (Postfix) with ESMTPS id 84AC65A061A for ; Fri, 24 Oct 2025 07:54:12 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gibson.dropbear.id.au; s=202510; t=1761285250; bh=C4L31/D9usvp0M8BsbvFq7hgnlbi+/bt2/v29QPonMI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=oSwMQJWsK4sIdwzdKdoimmNBH+C4QEuGd7mZwv9+43NG9t4hdM/8KEmhSKd1DWz20 BsFF7BN75IymH7foA+5o38tYt1CfVsLZe23bKq27hsmJy+KuxSKjSXjad9TorIibIZ 9NVSRAlVvnJ9rLjyVq8a74W7jdAB1hevFBIrFt0XPk1dUPLRmxMsPOGeCt6hKmzLeR xfS1yz8YZGKx+Dss18iK0BWMCnBnSdrVkMlMYSCPKl7QnFkuzMtNCe85Km7sRm/33E yysfRK1/7PAAWFT3PCaCPpwqPAp4PYrJumBl9UMpXKk1uy4jeoJei9fMTEti3gKVsT uk6mhNxo44Z9w== Received: by gandalf.ozlabs.org (Postfix, from userid 1007) id 4ctBtB2q3Tz4wML; Fri, 24 Oct 2025 16:54:10 +1100 (AEDT) Date: Fri, 24 Oct 2025 16:54:05 +1100 From: David Gibson To: Jon Maloy Subject: Re: [PATCH v15 4/9] arp/ndp: send ARP announcement / unsolicited NA when neigbour entry added Message-ID: References: <20251024012933.1933642-1-jmaloy@redhat.com> <20251024012933.1933642-5-jmaloy@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="Ouvp2jIwBVkexIV7" Content-Disposition: inline In-Reply-To: <20251024012933.1933642-5-jmaloy@redhat.com> Message-ID-Hash: 7LVL3CP6G7C6TM3BDSIGMWOA7G4C4Z3R X-Message-ID-Hash: 7LVL3CP6G7C6TM3BDSIGMWOA7G4C4Z3R X-MailFrom: dgibson@gandalf.ozlabs.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: sbrivio@redhat.com, dgibson@redhat.com, passt-dev@passt.top X-Mailman-Version: 3.3.8 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: --Ouvp2jIwBVkexIV7 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Oct 23, 2025 at 09:29:28PM -0400, Jon Maloy wrote: > ARP announcements and unsolicited NAs should be handled with caution > because of the risk of malignant users emitting them to disturb > network communication. >=20 > There is however one case we where we know it is legitimate > and safe for us to send out such messages: The one time we switch > from using ctx->own_tap_mac to a MAC address received via the > recently added neigbour subscription function. Later changes to > the MAC address of a host in an existing entry cannot be fully > trusted, so we abstain from doing it in such cases. >=20 > When sending this type of messages, we notice that the guest accepts > the update, but shortly later asks for a confirmation in the form of > a regular ARP/NS request. This is responded to with the new value, > and we have exactly the effect we wanted. >=20 > This commit adds this functionality. >=20 > Signed-off-by: Jon Maloy Reviewed-by: David Gibson --=20 David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson --Ouvp2jIwBVkexIV7 Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEEO+dNsU4E3yXUXRK2zQJF27ox2GcFAmj7FHwACgkQzQJF27ox 2GfE5g//UBAzD+1UuxTLDiRhhuoQRB3ntp6gXY05/mSnfO1NQa8KbRHyRDikmg/o l4KLeMWQ7Q/i6QEuyqu0/+39TAHqMkhQvvAHOOq4KZNm0anm6GcInTLBS7GNUMGQ xMxLrMePoR6RGNGLRlOs4p6uYSYXNHF7UayADLW/1xrwVRspntZOJMvn93b/h7H9 UBpkF5oV/bnCADbLaHUx9SAdqUClaDRywvXfslAYvNCj25NasnbNsS9ibW8fCFDr oKEhIJnmnK6w5ayExRHFmyxPBEK0MC3u5Gh7tXqMfo/dLhbkLMTynPx16WUjHZJt i+Q+K32QGOrxSAUdIc/BpgTKPuhLzWZspV2FNBZfzmB9o8qqI9qHsqAF6WyIVLO9 K3ilq1sleyUCMvfur9btLU9sHxA94w/hkEEFhshL7YkEIdGEDsyaS32MqjtUofbw 8fq25AqpUqQEYX4USTK6lyoji9yb74RaGh/QvKtq+oWfqv9Bz8vLAvr3TEIfd1a5 kTsZZAdVu9VZMMjr7ccP0KB6261f8jsEnZ883e8DkPWP0MOXw/wuGCFSzq78yKhB zSLXGg8qAjb6wJcdXxRm8lfKKNa3oZD2Z3Eu6cRBZHBnQxKJidRx2bOK6bbkOT3/ Os2noM6RNX2If1Bif7yPEy8Mb/6dU0RKPAZOJXvTOQDUqmOeiSs= =msWy -----END PGP SIGNATURE----- --Ouvp2jIwBVkexIV7--