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=202508 header.b=bBK57ZLc; dkim-atps=neutral Received: from mail.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by passt.top (Postfix) with ESMTPS id 724315A0271 for ; Thu, 18 Sep 2025 04:43:44 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gibson.dropbear.id.au; s=202508; t=1758163421; bh=kUIJ+px5gXtMMpLRNdo/W0w4nTSYFUnViJZcNntJJfk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=bBK57ZLcZZEFWknnlLvDeHOicdSijOo/55BrPKh7He9lnGWOsoN8hC05C1AjEv8Hi LEmZHmHlFw0qaFbzFLfZiD1LTRDDI90oagEhpc/YKqTmcZTUiBVZmeF3Xpq6h08nKe fCll8DHmJZZ7IdkvzZMWKoZBgUeOJpCyWBRWESNTt8QTEXfDUQN33URDuGSakTagXf vEqwLIovfaMfN9AfSWES+Wu7k0qSIjlOKteyGuh+leJ3Gv7GYJbRyuAuugnAa4j3XT pVqKNFmcXmF7r2jENYL+Pq9nltg6wp9LLWxa9YrTPtEOml+AeuOnNHoyYDYmKXbL/8 65uBfoPjlffug== Received: by gandalf.ozlabs.org (Postfix, from userid 1007) id 4cS0M156Crz4wCB; Thu, 18 Sep 2025 12:43:41 +1000 (AEST) Date: Thu, 18 Sep 2025 12:43:30 +1000 From: David Gibson To: Volker Diels-Grabsch Subject: Re: [PATCH 5/5] Improve clarity of comment Message-ID: References: <20250916192209.3986375-1-v@njh.eu> <20250916192209.3986375-6-v@njh.eu> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="txMw4frNTsH4X4Gk" Content-Disposition: inline In-Reply-To: <20250916192209.3986375-6-v@njh.eu> Message-ID-Hash: EHPRX63IXBCKL2SS3QFMAQRNB7GYDDP2 X-Message-ID-Hash: EHPRX63IXBCKL2SS3QFMAQRNB7GYDDP2 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: 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: --txMw4frNTsH4X4Gk Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Sep 16, 2025 at 09:21:16PM +0200, Volker Diels-Grabsch wrote: > The new wording clarifies that we (1) use the broadcast MAC address > only until we know the actual MAC address of the guest, and (2) our > first packets will not necessarily "reach" the guest, in the sense of > being processed rather than dropped. (Which is why we actively send an > initial ARP and/or NDP message, to get the guest MAC address as soon > as possible.) >=20 > Signed-off-by: Volker Diels-Grabsch Reviewed-by: David Gibson > --- > tap.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) >=20 > diff --git a/tap.c b/tap.c > index 0f8ee25..399eeaa 100644 > --- a/tap.c > +++ b/tap.c > @@ -1512,9 +1512,9 @@ void tap_backend_init(struct ctx *c) > case MODE_PASST: > tap_sock_unix_init(c); > =20 > - /* In passt mode, we don't know the guest's MAC address until it > - * sends us packets. Use the broadcast address so that our > - * first packets will reach it. > + /* In passt mode, we don't know the guest's MAC address until > + * it sends us packets. Until then, use the broadcast address > + * so that our first packets will have a chance to reach it. > */ > memcpy(&c->guest_mac, MAC_BROADCAST, sizeof(c->guest_mac)); > break; > --=20 > 2.47.3 >=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 --txMw4frNTsH4X4Gk Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEEO+dNsU4E3yXUXRK2zQJF27ox2GcFAmjLccEACgkQzQJF27ox 2GdWNw/9G5m61/GA0OCWw+hyk376Y0nHHr4aMQTk8DzdHl+/SE7DZ3ovI4OvOhjB X5Af+qGUrPSM0xf+I13DgJcAmnfivqmeWn0ZZGTiY86JiR0KJE0X9Hlnj4i9tHkF B4+UKk7jmI/oVrsRfHoEaVCZfbfKtUFTljL4nXlWRJ1/M0pIYjg5k/EKhCYqBvDD +SzRF7Jt1kiPJVezm71aF4LEltHwYK52kSxLx3cvoFEeBEFICy/0pFYvZP+GpZZ2 t9evnqia5QEPxgBMvn0wNWRNELsok0VPczlB7Ltbvrgy79YgPxNjyIDcx1b/7NI3 GCQUF9o4FFzSRrApdb5cH6A0KbOZTptGzHvoA6D2wAhG3I98rZ+aE5cp3fUvWYXC 8PEiwwPNw6q7m5685C9BSCJBg5hJ1rp8zp5iQ8lZaSt6p5jmi2Iq9CNchny6ua8g lp+hHl2Km/9cK+z3FAdUf/e6lIbm+hlxGnyI/gADO5Xv5udTa3nDs4Gj6pkbkp47 m4pMKfAAA2WVYsQuCE2UxqH6B8qIZWqpEF9z6dZP3A/iewQ8+uLDSeMK8BpLX+qi zWHL/HWubCegaoy7vDBlFe99CP+/kAWta5AcrtAVGmMB1uuYQmF5z5L7GmHQR7J5 LvVU7RiOlbTCyKPdBrRtB8wy2LZxD4nEP4QlVwD8Nb629rTeHUs= =BIzB -----END PGP SIGNATURE----- --txMw4frNTsH4X4Gk--