From: Stefan Berger Date: Fri, 19 Feb 2010 10:38:57 +0000 (+0100) Subject: macvtap IFF_VNET_HDR configuration X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=e52687e88fa167232cd8c314016fa9084fee72b2;p=people%2Fliuw%2Flibxenctrl-split%2Flibvirt.git macvtap IFF_VNET_HDR configuration This patch sets or unsets the IFF_VNET_HDR flag depending on what device is used in the VM. The manipulation of the flag is done in the open function and is only fatal if the IFF_VNET_HDR flag could not be cleared although it has to be (or if an ioctl generally fails). In that case the macvtap tap is closed again and the macvtap interface torn. * src/qemu/qemu_conf.c src/qemu/qemu_conf.h: pass qemuCmdFlags to qemudPhysIfaceConnect() * src/util/macvtap.c src/util/macvtap.h: add vnet_hdr boolean to openMacvtapTap(), and private function configMacvtapTap() * src/qemu/qemu_driver.c: add extra qemuCmdFlags when calling qemudPhysIfaceConnect() --- diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c index 8f91d07af..dcd2ce76a 100644 --- a/src/qemu/qemu_conf.c +++ b/src/qemu/qemu_conf.c @@ -1434,14 +1434,20 @@ int qemudPhysIfaceConnect(virConnectPtr conn, virDomainNetDefPtr net, char *linkdev, - int brmode) + int brmode, + unsigned long long qemuCmdFlags) { int rc; #if WITH_MACVTAP char *res_ifname = NULL; + int vnet_hdr = 0; + + if (qemuCmdFlags & QEMUD_CMD_FLAG_VNET_HDR && + net->model && STREQ(net->model, "virtio")) + vnet_hdr = 1; rc = openMacvtapTap(conn, net->ifname, net->mac, linkdev, brmode, - &res_ifname); + &res_ifname, vnet_hdr); if (rc >= 0) { VIR_FREE(net->ifname); net->ifname = res_ifname; @@ -1451,6 +1457,7 @@ qemudPhysIfaceConnect(virConnectPtr conn, (void)net; (void)linkdev; (void)brmode; + (void)qemuCmdFlags; qemuReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("No support for macvtap device")); rc = -1; @@ -3752,7 +3759,8 @@ int qemudBuildCommandLine(virConnectPtr conn, } else if (net->type == VIR_DOMAIN_NET_TYPE_DIRECT) { int tapfd = qemudPhysIfaceConnect(conn, net, net->data.direct.linkdev, - net->data.direct.mode); + net->data.direct.mode, + qemuCmdFlags); if (tapfd < 0) goto error; diff --git a/src/qemu/qemu_conf.h b/src/qemu/qemu_conf.h index 4f35a9cb3..b25c300d9 100644 --- a/src/qemu/qemu_conf.h +++ b/src/qemu/qemu_conf.h @@ -253,7 +253,8 @@ int qemudNetworkIfaceConnect (virConnectPtr conn, int qemudPhysIfaceConnect(virConnectPtr conn, virDomainNetDefPtr net, char *linkdev, - int brmode); + int brmode, + unsigned long long qemuCmdFlags); int qemudProbeMachineTypes (const char *binary, virCapsGuestMachinePtr **machines, diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 0fb2413b1..3d121fb58 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -5725,7 +5725,8 @@ static int qemudDomainAttachNetDevice(virConnectPtr conn, if ((tapfd = qemudPhysIfaceConnect(conn, net, net->data.direct.linkdev, - net->data.direct.mode)) < 0) + net->data.direct.mode, + qemuCmdFlags)) < 0) return -1; } diff --git a/src/util/macvtap.c b/src/util/macvtap.c index 88a64ceb8..8c2958896 100644 --- a/src/util/macvtap.c +++ b/src/util/macvtap.c @@ -614,6 +614,64 @@ macvtapModeFromInt(enum virDomainNetdevMacvtapType mode) } +/** + * configMacvtapTap: + * @tapfd: file descriptor of the macvtap tap + * @vnet_hdr: 1 to enable IFF_VNET_HDR, 0 to disable it + * + * Returns 0 on success, -1 in case of fatal error, error code otherwise. + * + * Turn the IFF_VNET_HDR flag, if requested and available, make sure + * it's off in the other cases. + * A fatal error is defined as the VNET_HDR flag being set but it cannot + * be turned off for some reason. This is reported with -1. Other fatal + * error is not being able to read the interface flags. In that case the + * macvtap device should not be used. + */ +static int +configMacvtapTap(int tapfd, int vnet_hdr) +{ + unsigned int features; + struct ifreq ifreq; + short new_flags = 0; + int rc_on_fail = 0; + const char *errmsg = NULL; + + memset(&ifreq, 0, sizeof(ifreq)); + + if (ioctl(tapfd, TUNGETIFF, &ifreq) < 0) { + virReportSystemError(errno, "%s", + _("cannot get interface flags on macvtap tap")); + return -1; + } + + new_flags = ifreq.ifr_flags; + + if ((ifreq.ifr_flags & IFF_VNET_HDR) && !vnet_hdr) { + new_flags = ifreq.ifr_flags & ~IFF_VNET_HDR; + rc_on_fail = -1; + errmsg = _("cannot clean IFF_VNET_HDR flag on macvtap tap"); + } else if ((ifreq.ifr_flags & IFF_VNET_HDR) == 0 && vnet_hdr) { + if (ioctl(tapfd, TUNGETFEATURES, &features) != 0) + return errno; + if ((features & IFF_VNET_HDR)) { + new_flags = ifreq.ifr_flags | IFF_VNET_HDR; + errmsg = _("cannot set IFF_VNET_HDR flag on macvtap tap"); + } + } + + if (new_flags != ifreq.ifr_flags) { + ifreq.ifr_flags = new_flags; + if (ioctl(tapfd, TUNSETIFF, &ifreq) < 0) { + virReportSystemError(errno, "%s", errmsg); + return rc_on_fail; + } + } + + return 0; +} + + /** * openMacvtapTap: * Create an instance of a macvtap device and open its tap character @@ -640,7 +698,8 @@ openMacvtapTap(virConnectPtr conn, const unsigned char *macaddress, const char *linkdev, int mode, - char **res_ifname) + char **res_ifname, + int vnet_hdr) { const char *type = "macvtap"; int c, rc; @@ -699,9 +758,14 @@ create_name: rc = openTap(cr_ifname, 10); - if (rc >= 0) + if (rc >= 0) { + if (configMacvtapTap(rc, vnet_hdr) < 0) { + close(rc); + rc = -1; + goto link_del_exit; + } *res_ifname = strdup(cr_ifname); - else + } else goto link_del_exit; return rc; diff --git a/src/util/macvtap.h b/src/util/macvtap.h index a1a0a7a8a..4c2fe8acd 100644 --- a/src/util/macvtap.h +++ b/src/util/macvtap.h @@ -33,9 +33,10 @@ int openMacvtapTap(virConnectPtr conn, const unsigned char *macaddress, const char *linkdev, int mode, - char **res_ifname); + char **res_ifname, + int vnet_hdr); -void delMacvtap(const char *name); +void delMacvtap(const char *ifname); #endif /* WITH_MACVTAP */