From nobody Wed Nov 5 17:18:45 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1496858352928239.38598708760105; Wed, 7 Jun 2017 10:59:12 -0700 (PDT) Received: from localhost ([::1]:45546 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dIfEc-0000xt-EQ for importer@patchew.org; Wed, 07 Jun 2017 13:59:10 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55152) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dIfAA-0005LJ-EQ for qemu-devel@nongnu.org; Wed, 07 Jun 2017 13:54:35 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dIfA7-0007tG-O2 for qemu-devel@nongnu.org; Wed, 07 Jun 2017 13:54:34 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50944) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dIfA7-0007su-G1 for qemu-devel@nongnu.org; Wed, 07 Jun 2017 13:54:31 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 7BD7C3DBE3; Wed, 7 Jun 2017 17:54:30 +0000 (UTC) Received: from t460.redhat.com (ovpn-117-221.ams2.redhat.com [10.36.117.221]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3EE617E66E; Wed, 7 Jun 2017 17:54:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 7BD7C3DBE3 Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=berrange@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 7BD7C3DBE3 From: "Daniel P. Berrange" To: qemu-devel@nongnu.org Date: Wed, 7 Jun 2017 18:54:15 +0100 Message-Id: <20170607175419.13558-2-berrange@redhat.com> In-Reply-To: <20170607175419.13558-1-berrange@redhat.com> References: <20170607175419.13558-1-berrange@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Wed, 07 Jun 2017 17:54:30 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL v1 1/5] sockets: ensure we can bind to both ipv4 & ipv6 separately X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Type: text/plain; charset="utf-8" When binding to an IPv6 socket we currently force the IPV6_V6ONLY flag to off. This means that the IPv6 socket will accept both IPv4 & IPv6 sockets when QEMU is launched with something like -vnc :::1 While this is good for that case, it is bad for other cases. For example if an empty hostname is given, getaddrinfo resolves it to 2 addresses 0.0.0.0 and ::, in that order. We will thus bind to 0.0.0.0 first, and then fail to bind to :: on the same port. The same problem can happen if any other hostname lookup causes the IPv4 address to be reported before the IPv6 address. When we get an IPv6 bind failure, we should re-try the same port, but with IPV6_V6ONLY turned on again, to avoid clash with any IPv4 listener. This ensures that -vnc :1 will bind successfully to both 0.0.0.0 and ::, and also avoid -vnc :1,to=3D2 from mistakenly using a 2nd port for the :: listener. Acked-by: Gerd Hoffmann Reviewed-by: Eric Blake Reviewed-by: Philippe Mathieu-Daud=C3=A9 Signed-off-by: Daniel P. Berrange --- util/qemu-sockets.c | 31 +++++++++++++++++++++++-------- 1 file changed, 23 insertions(+), 8 deletions(-) diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c index b39ae74..8720097 100644 --- a/util/qemu-sockets.c +++ b/util/qemu-sockets.c @@ -208,22 +208,37 @@ static int inet_listen_saddr(InetSocketAddress *saddr, } =20 socket_set_fast_reuse(slisten); -#ifdef IPV6_V6ONLY - if (e->ai_family =3D=3D PF_INET6) { - /* listen on both ipv4 and ipv6 */ - const int off =3D 0; - qemu_setsockopt(slisten, IPPROTO_IPV6, IPV6_V6ONLY, &off, - sizeof(off)); - } -#endif =20 port_min =3D inet_getport(e); port_max =3D saddr->has_to ? saddr->to + port_offset : port_min; for (p =3D port_min; p <=3D port_max; p++) { +#ifdef IPV6_V6ONLY + /* listen on both ipv4 and ipv6 */ + int v6only =3D 0; +#endif inet_setport(e, p); +#ifdef IPV6_V6ONLY + rebind: + if (e->ai_family =3D=3D PF_INET6) { + qemu_setsockopt(slisten, IPPROTO_IPV6, IPV6_V6ONLY, &v6onl= y, + sizeof(v6only)); + } +#endif if (bind(slisten, e->ai_addr, e->ai_addrlen) =3D=3D 0) { goto listen; } + +#ifdef IPV6_V6ONLY + /* If we got EADDRINUSE from an IPv6 bind & V6ONLY is unset, + * it could be that the IPv4 port is already claimed, so retry + * with V6ONLY set + */ + if (e->ai_family =3D=3D PF_INET6 && errno =3D=3D EADDRINUSE &&= !v6only) { + v6only =3D 1; + goto rebind; + } +#endif + if (p =3D=3D port_max) { if (!e->ai_next) { error_setg_errno(errp, errno, "Failed to bind socket"); --=20 2.9.3