From patchwork Wed Oct 21 11:27:45 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark McLoughlin X-Patchwork-Id: 36536 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [199.232.76.165]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id DC0DBB7B9D for ; Wed, 21 Oct 2009 23:40:30 +1100 (EST) Received: from localhost ([127.0.0.1]:49423 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1N0aUM-0007h0-Vy for incoming@patchwork.ozlabs.org; Wed, 21 Oct 2009 08:40:27 -0400 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1N0ZOD-0006mG-DE for qemu-devel@nongnu.org; Wed, 21 Oct 2009 07:30:02 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1N0ZO5-0006gG-0j for qemu-devel@nongnu.org; Wed, 21 Oct 2009 07:29:58 -0400 Received: from [199.232.76.173] (port=57332 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1N0ZO3-0006eT-0c for qemu-devel@nongnu.org; Wed, 21 Oct 2009 07:29:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40526) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1N0ZO2-0002xW-BM for qemu-devel@nongnu.org; Wed, 21 Oct 2009 07:29:50 -0400 Received: from int-mx03.intmail.prod.int.phx2.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.16]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id n9LBTnHm014737 for ; Wed, 21 Oct 2009 07:29:49 -0400 Received: from blaa.localdomain (ovpn01.gateway.prod.ext.phx2.redhat.com [10.5.9.1]) by int-mx03.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id n9LBTnZF002042; Wed, 21 Oct 2009 07:29:49 -0400 Received: by blaa.localdomain (Postfix, from userid 500) id 074D9462C3; Wed, 21 Oct 2009 12:27:58 +0100 (IST) From: Mark McLoughlin To: qemu-devel@nongnu.org Date: Wed, 21 Oct 2009 12:27:45 +0100 Message-Id: <1256124478-2988-7-git-send-email-markmc@redhat.com> In-Reply-To: <1256124478-2988-1-git-send-email-markmc@redhat.com> References: <1256124478-2988-1-git-send-email-markmc@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.16 X-detected-operating-system: by monty-python.gnu.org: Genre and OS details not recognized. Cc: Mark McLoughlin Subject: [Qemu-devel] [PATCH 06/19] net: add a vnet_hdr=on|off parameter X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org This allows people to disable the IFF_VNET_HDR flag, e.g. for debugging purposes or if they know they may migrate the guest to a machine without IFF_VNET_HDR support. It also allows making the lack of IFF_VNET_HDR support an error condition, e.g. in the case where a guest is being migrated from a host which does support it. Signed-off-by: Mark McLoughlin --- net.c | 42 ++++++++++++++++++++++++++++++++---------- qemu-options.hx | 4 +++- 2 files changed, 35 insertions(+), 11 deletions(-) diff --git a/net.c b/net.c index fccabdb..d62ab7b 100644 --- a/net.c +++ b/net.c @@ -1479,7 +1479,8 @@ static TAPState *net_tap_fd_init(VLANState *vlan, } #if defined (CONFIG_BSD) || defined (__FreeBSD_kernel__) -static int tap_open(char *ifname, int ifname_size, int *vnet_hdr) +static int tap_open(char *ifname, int ifname_size, + int *vnet_hdr, int vnet_hdr_required) { int fd; char *dev; @@ -1621,7 +1622,8 @@ static int tap_alloc(char *dev, size_t dev_size) return tap_fd; } -static int tap_open(char *ifname, int ifname_size, int *vnet_hdr) +static int tap_open(char *ifname, int ifname_size, + int *vnet_hdr, int vnet_hdr_required) { char dev[10]=""; int fd; @@ -1634,13 +1636,15 @@ static int tap_open(char *ifname, int ifname_size, int *vnet_hdr) return fd; } #elif defined (_AIX) -static int tap_open(char *ifname, int ifname_size, int *vnet_hdr) +static int tap_open(char *ifname, int ifname_size, + int *vnet_hdr, int vnet_hdr_required) { fprintf (stderr, "no tap on AIX\n"); return -1; } #else -static int tap_open(char *ifname, int ifname_size, int *vnet_hdr) +static int tap_open(char *ifname, int ifname_size, + int *vnet_hdr, int vnet_hdr_required) { struct ifreq ifr; int fd, ret; @@ -1653,7 +1657,7 @@ static int tap_open(char *ifname, int ifname_size, int *vnet_hdr) memset(&ifr, 0, sizeof(ifr)); ifr.ifr_flags = IFF_TAP | IFF_NO_PI; - { + if (*vnet_hdr) { unsigned int features; if (ioctl(fd, TUNGETFEATURES, &features) == 0 && @@ -1661,6 +1665,13 @@ static int tap_open(char *ifname, int ifname_size, int *vnet_hdr) *vnet_hdr = 1; ifr.ifr_flags |= IFF_VNET_HDR; } + + if (vnet_hdr_required && !*vnet_hdr) { + qemu_error("vnet_hdr=1 requested, but no kernel " + "support for IFF_VNET_HDR available"); + close(fd); + return -1; + } } if (ifname[0] != '\0') @@ -1725,7 +1736,7 @@ static int launch_script(const char *setup_script, const char *ifname, int fd) static int net_tap_init(QemuOpts *opts, int *vnet_hdr) { - int fd; + int fd, vnet_hdr_required; char ifname[128] = {0,}; const char *setup_script; @@ -1733,8 +1744,14 @@ static int net_tap_init(QemuOpts *opts, int *vnet_hdr) pstrcpy(ifname, sizeof(ifname), qemu_opt_get(opts, "ifname")); } - *vnet_hdr = 0; - TFR(fd = tap_open(ifname, sizeof(ifname), vnet_hdr)); + *vnet_hdr = qemu_opt_get_bool(opts, "vnet_hdr", 1); + if (qemu_opt_get(opts, "vnet_hdr")) { + vnet_hdr_required = *vnet_hdr; + } else { + vnet_hdr_required = 0; + } + + TFR(fd = tap_open(ifname, sizeof(ifname), vnet_hdr, vnet_hdr_required)); if (fd < 0) { return -1; } @@ -2683,8 +2700,9 @@ static int net_init_tap(QemuOpts *opts, if (qemu_opt_get(opts, "fd")) { if (qemu_opt_get(opts, "ifname") || qemu_opt_get(opts, "script") || - qemu_opt_get(opts, "downscript")) { - qemu_error("ifname=, script= and downscript= is invalid with fd=\n"); + qemu_opt_get(opts, "downscript") || + qemu_opt_get(opts, "vnet_hdr")) { + qemu_error("ifname=, script=, downscript= and vnet_hdr= is invalid with fd=\n"); return -1; } @@ -3040,6 +3058,10 @@ static struct { .name = "sndbuf", .type = QEMU_OPT_SIZE, .help = "send buffer limit" + }, { + .name = "vnet_hdr", + .type = QEMU_OPT_BOOL, + .help = "enable the IFF_VNET_HDR flag on the tap interface" }, { /* end of list */ } }, diff --git a/qemu-options.hx b/qemu-options.hx index c745e0c..d78b738 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -810,7 +810,7 @@ DEF("net", HAS_ARG, QEMU_OPTION_net, "-net tap[,vlan=n][,name=str],ifname=name\n" " connect the host TAP network interface to VLAN 'n'\n" #else - "-net tap[,vlan=n][,name=str][,fd=h][,ifname=name][,script=file][,downscript=dfile][,sndbuf=nbytes]\n" + "-net tap[,vlan=n][,name=str][,fd=h][,ifname=name][,script=file][,downscript=dfile][,sndbuf=nbytes][,vnet_hdr=on|off]\n" " connect the host TAP network interface to VLAN 'n' and use the\n" " network scripts 'file' (default=%s)\n" " and 'dfile' (default=%s);\n" @@ -818,6 +818,8 @@ DEF("net", HAS_ARG, QEMU_OPTION_net, " use 'fd=h' to connect to an already opened TAP interface\n" " use 'sndbuf=nbytes' to limit the size of the send buffer; the\n" " default of 'sndbuf=1048576' can be disabled using 'sndbuf=0'\n" + " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag; use\n" + " vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" #endif "-net socket[,vlan=n][,name=str][,fd=h][,listen=[host]:port][,connect=host:port]\n" " connect the vlan 'n' to another VLAN using a socket connection\n"