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=202512 header.b=fz23WhO7; dkim-atps=neutral Received: from mail.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by passt.top (Postfix) with ESMTPS id 92DDD5A068E for ; Mon, 05 Jan 2026 05:26:44 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gibson.dropbear.id.au; s=202512; t=1767587201; bh=FySFp2xzh+cibjbTWvcAhbXsrhqZmtZ1pnTCpCV2mVk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=fz23WhO7+vNC5qAOv8pr1+/NBIHOozIcTpuSnhE7isStxCjz4p1A5E/ryPEWj5fx0 XFaRGG/OEELzJ1dzwsdqCP+nedoxYw1mkfRnx3XpxGFJ99UO2OY2brfk9tzDkfERJ+ /1Uj45hVo98GTa1tbx4ZWoLjAQRQfE2wW/BEW55RazUyRnAqlMqsV9OmMFabxl4NuN nyspIouCG2DDRJpi1c9ClUhlFNOotF+RU3X+S7LEzZ6OpHP9ZqMud3Y6+2XrZ+qJto NQPaRX3HjB+DAoGcYgDs6I4AUZdFUP3g18s1ycPXpf3FR8dz9d8qjNxGRNAWYsVmr/ h3nHn13xjEMbw== Received: by gandalf.ozlabs.org (Postfix, from userid 1007) id 4dl1TY3mFWz4wCZ; Mon, 05 Jan 2026 15:26:41 +1100 (AEDT) Date: Mon, 5 Jan 2026 15:26:34 +1100 From: David Gibson To: Stefano Brivio Subject: Re: Thoughts on interface modes / multiple guest addresses Message-ID: References: <20251217012936.5aefec93@elisabeth> <20251218002220.18311a7b@elisabeth> <20251218063249.095e7614@elisabeth> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="3qvASH5zMZNEu2+x" Content-Disposition: inline In-Reply-To: <20251218063249.095e7614@elisabeth> Message-ID-Hash: BR2FCTNFB67H6LOR4OKPPG7DGD36QGYT X-Message-ID-Hash: BR2FCTNFB67H6LOR4OKPPG7DGD36QGYT 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: Jon Maloy , 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: --3qvASH5zMZNEu2+x Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Dec 18, 2025 at 06:32:49AM +0100, Stefano Brivio wrote: > On Thu, 18 Dec 2025 14:47:06 +1100 > David Gibson wrote: >=20 > > For multi-address support there are at least four things to consider: >=20 > For the bits related https://bugs.passt.top/show_bug.cgi?id=3D141, I > thought Jon was working on a proposal. >=20 > > (a) What goes in our internal list of addresses to give the guest? > >=20 > > a.1. Everything listed with -a? >=20 > If anything is passed, yes, those, and just those (separately for IP > version), because the user is clearly overriding addresses (as > currently implemented and documented). So far, so good. But including both explicit addresses and host addresses seems potentially useful to me (especially for an intermittently online host). It's not the first step, but I think we want to think about how we'd allow this. > > a.2. Everything on the host? >=20 > No, because you can't assume you can configure all those addresses on > a single interface. Adding multiple interfaces is something we could > consider later. Hm, depends what you mean by "can". The only case I can see they really can't be configured on the same interface is if they're link-local. But AFAICT, there's nothing to really stop you putting any combination of global-scope addresses on a single interface. It will less resemble the host's configuration, but again, there are degrees of transparency not a single standard. > > a.3. Everything on the host template interface? >=20 > Everything on the host template interface if available (as currently > documented). As a first step, sure. > > a.4. A link local address we pick? >=20 > A link-local address if nothing else is available (as currently > documented). This will need to be permanent for the requirement we > already discussed months ago with Podman developers. Right, but if this is permanent it potentially conflicts with link-local addresses from the host interface > > a.5. Some combination of the above. > >=20 > > Unlike routes (that I can see), I'm pretty sure there are use cases > > where we want both host-copied addresses (for transparency) and > > explicit addresses (for a stable way of communicating with the host). >=20 > Podman needs some anyway if we start with link-local addresses, to > keep DNS resolution working. >=20 > The rest just looks beyond the scope of > https://bugs.passt.top/show_bug.cgi?id=3D141 to me. I won't stand in the > way of this discussion, of course, but I won't participate either, > because I really don't see it as a priority at the moment. >=20 > --=20 > Stefano >=20 --=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 --3qvASH5zMZNEu2+x Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEEO+dNsU4E3yXUXRK2zQJF27ox2GcFAmlbPXkACgkQzQJF27ox 2GcIQQ/+KIHcjJujh6UQe9yUPm+epICUUQ36/5aYPCXE7LOXDzcE8oAOcxtxVFCU wRup6nLORODYuy/wl+cfUurcdxsTsOWafQe2L5Sbz62IGMWuxXfl2IO/vYeDRxr8 O88VIQTJiR8C2hXGRWyhidXTWhbbfxhGzEVcAjKBnYsOZEGJ34y8/Vikpn6iapnq UvqZN39U9snDMfvwKVc3/kA+4TwnHAqpKXFvFBunxGZQCNQ/ou1YeNCXG20jbMgD WLx5bNx/2q99a0bSDCSy5nrZyEYDw19z5ZOFZTZcKbGot5VuvXhD+bR/Nev26ok2 ooPHgGdd80qxpWpdH8V6LMcma9bbbSABQc4HlK08Fe42I/GsYCo8gP0qjzMcReDW 9oV/g+rRQibxsSpwnkccZnwZu6sNqaTc3EPHQ8p8WQanPPKdbZr215u7c0WTLNXt jbiD099pQfoGijiulPYeEKKHBg8OMn8WKcir6MlpgDVE88KYVJ1pqE2dMH6VzHXG Yzj53Qdayb/bb0ksA00YsmcploMkwBVrd0MjolIqHnP7gWUZcif5A2G9pPZcUsGY ilGWIHBU8yp1hwP/tDRgaurS43fiFYEFMpDwuxTjaW5gW/zjHJh38fS4Xx8sNi6G DnYcUUNmQKP8el965qA7F+11cg1tNoji2f92j8ZHZcu3wUaAKt8= =aAw7 -----END PGP SIGNATURE----- --3qvASH5zMZNEu2+x--