libvirt/src/qemu/qemu_interface.c

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/*
* qemu_interface.c: QEMU interface management
*
* Copyright (C) 2015-2016 Red Hat, Inc.
* Copyright IBM Corp. 2014
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <http://www.gnu.org/licenses/>.
*/
#include <config.h>
#include "network_conf.h"
#include "domain_audit.h"
#include "domain_nwfilter.h"
#include "qemu_interface.h"
#include "viralloc.h"
#include "virlog.h"
#include "virstring.h"
#include "virnetdev.h"
#include "virnetdevtap.h"
#include "virnetdevmacvlan.h"
#include "virnetdevbridge.h"
#include "virnetdevvportprofile.h"
#include "virsocket.h"
#include <sys/stat.h>
#include <fcntl.h>
#define VIR_FROM_THIS VIR_FROM_QEMU
VIR_LOG_INIT("qemu.qemu_interface");
/**
* qemuInterfaceStartDevice:
* @net: net device to start
*
* Based upon the type of device provided, perform the appropriate
* work to completely activate the device and make it reachable from
* the rest of the network.
*/
int
qemuInterfaceStartDevice(virDomainNetDefPtr net)
{
virDomainNetType actualType = virDomainNetGetActualType(net);
switch (actualType) {
case VIR_DOMAIN_NET_TYPE_BRIDGE:
case VIR_DOMAIN_NET_TYPE_NETWORK:
if (virDomainNetGetActualBridgeMACTableManager(net)
== VIR_NETWORK_BRIDGE_MAC_TABLE_MANAGER_LIBVIRT) {
/* libvirt is managing the FDB of the bridge this device
* is attaching to, so we have turned off learning and
* unicast_flood on the device to prevent the kernel from
* adding any FDB entries for it. This means we need to
* add an fdb entry ourselves, using the MAC address from
* the interface config.
*/
if (virNetDevBridgeFDBAdd(&net->mac, net->ifname,
VIR_NETDEVBRIDGE_FDB_FLAG_MASTER |
VIR_NETDEVBRIDGE_FDB_FLAG_TEMP) < 0)
return -1;
}
break;
case VIR_DOMAIN_NET_TYPE_DIRECT: {
const char *physdev = virDomainNetGetActualDirectDev(net);
bool isOnline = true;
/* set the physdev online if necessary. It may already be up,
* in which case we shouldn't re-up it just in case that causes
* some sort of "blip" in the physdev's status.
*/
if (physdev && virNetDevGetOnline(physdev, &isOnline) < 0)
return -1;
if (!isOnline && virNetDevSetOnline(physdev, true) < 0)
return -1;
/* macvtap devices share their MAC address with the guest
* domain, and if they are set online prior to the domain CPUs
* being started, the host may send out traffic from this
* device that could confuse other entities on the network (in
* particular, if this new domain is the destination of a
* migration, and the source domain is still running, another
* host may mistakenly direct traffic for the guest to the
* destination domain rather than source domain). To prevent
* this, we create the macvtap device with IFF_UP false
* (i.e. "offline") then wait to bring it online until just as
* we are starting the domain CPUs.
*/
if (virNetDevSetOnline(net->ifname, true) < 0)
return -1;
break;
}
case VIR_DOMAIN_NET_TYPE_ETHERNET:
if (virNetDevIPInfoAddToDev(net->ifname, &net->hostIP) < 0)
return -1;
break;
case VIR_DOMAIN_NET_TYPE_USER:
case VIR_DOMAIN_NET_TYPE_VHOSTUSER:
case VIR_DOMAIN_NET_TYPE_SERVER:
case VIR_DOMAIN_NET_TYPE_CLIENT:
case VIR_DOMAIN_NET_TYPE_MCAST:
case VIR_DOMAIN_NET_TYPE_UDP:
case VIR_DOMAIN_NET_TYPE_INTERNAL:
case VIR_DOMAIN_NET_TYPE_HOSTDEV:
case VIR_DOMAIN_NET_TYPE_VDPA:
case VIR_DOMAIN_NET_TYPE_LAST:
/* these types all require no action */
break;
}
return 0;
}
/**
* qemuInterfaceStartDevices:
* @def: domain definition
*
* Set all ifaces associated with this domain to the online state.
*/
int
qemuInterfaceStartDevices(virDomainDefPtr def)
{
size_t i;
for (i = 0; i < def->nnets; i++) {
if (qemuInterfaceStartDevice(def->nets[i]) < 0)
return -1;
}
return 0;
}
/**
* qemuInterfaceStopDevice:
* @net: net device to stop
*
* Based upon the type of device provided, perform the appropriate
* work to deactivate the device so that packets aren't forwarded to
* it from the rest of the network.
*/
int
qemuInterfaceStopDevice(virDomainNetDefPtr net)
{
virDomainNetType actualType = virDomainNetGetActualType(net);
switch (actualType) {
case VIR_DOMAIN_NET_TYPE_BRIDGE:
case VIR_DOMAIN_NET_TYPE_NETWORK:
if (virDomainNetGetActualBridgeMACTableManager(net)
== VIR_NETWORK_BRIDGE_MAC_TABLE_MANAGER_LIBVIRT) {
/* remove the FDB entries that were added during
* qemuInterfaceStartDevices()
*/
if (virNetDevBridgeFDBDel(&net->mac, net->ifname,
VIR_NETDEVBRIDGE_FDB_FLAG_MASTER |
VIR_NETDEVBRIDGE_FDB_FLAG_TEMP) < 0)
return -1;
}
break;
case VIR_DOMAIN_NET_TYPE_DIRECT: {
const char *physdev = virDomainNetGetActualDirectDev(net);
/* macvtap interfaces need to be marked !IFF_UP (ie "down") to
* prevent any host-generated traffic sent from this interface
* from putting bad info into the arp caches of other machines
* on this network.
*/
if (virNetDevSetOnline(net->ifname, false) < 0)
return -1;
/* also mark the physdev down for passthrough macvtap, as the
* physdev has the same MAC address as the macvtap device.
*/
if (virDomainNetGetActualDirectMode(net) ==
VIR_NETDEV_MACVLAN_MODE_PASSTHRU &&
physdev && virNetDevSetOnline(physdev, false) < 0)
return -1;
break;
}
case VIR_DOMAIN_NET_TYPE_ETHERNET:
case VIR_DOMAIN_NET_TYPE_USER:
case VIR_DOMAIN_NET_TYPE_VHOSTUSER:
case VIR_DOMAIN_NET_TYPE_SERVER:
case VIR_DOMAIN_NET_TYPE_CLIENT:
case VIR_DOMAIN_NET_TYPE_MCAST:
case VIR_DOMAIN_NET_TYPE_UDP:
case VIR_DOMAIN_NET_TYPE_INTERNAL:
case VIR_DOMAIN_NET_TYPE_HOSTDEV:
case VIR_DOMAIN_NET_TYPE_VDPA:
case VIR_DOMAIN_NET_TYPE_LAST:
/* these types all require no action */
break;
}
return 0;
}
/**
* qemuInterfaceStopDevices:
* @def: domain definition
*
* Make all interfaces associated with this domain inaccessible from
* the rest of the network.
*/
int
qemuInterfaceStopDevices(virDomainDefPtr def)
{
size_t i;
for (i = 0; i < def->nnets; i++) {
if (qemuInterfaceStopDevice(def->nets[i]) < 0)
return -1;
}
return 0;
}
static bool
qemuInterfaceIsVnetCompatModel(const virDomainNetDef *net)
{
return (virDomainNetIsVirtioModel(net) ||
net->model == VIR_DOMAIN_NET_MODEL_E1000E ||
net->model == VIR_DOMAIN_NET_MODEL_VMXNET3);
}
/**
* qemuInterfaceDirectConnect:
* @def: the definition of the VM (needed by 802.1Qbh and audit)
* @driver: pointer to the driver instance
* @net: pointer to the VM's interface description with direct device type
* @tapfd: array of file descriptor return value for the new device
* @tapfdSize: number of file descriptors in @tapfd
* @vmop: VM operation type
*
* Returns 0 on success or -1 in case of error.
*/
int
qemuInterfaceDirectConnect(virDomainDefPtr def,
virQEMUDriverPtr driver,
virDomainNetDefPtr net,
int *tapfd,
size_t tapfdSize,
virNetDevVPortProfileOp vmop)
{
int ret = -1;
char *res_ifname = NULL;
g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(driver);
unsigned int macvlan_create_flags = VIR_NETDEV_MACVLAN_CREATE_WITH_TAP;
if (qemuInterfaceIsVnetCompatModel(net))
macvlan_create_flags |= VIR_NETDEV_MACVLAN_VNET_HDR;
if (virNetDevMacVLanCreateWithVPortProfile(net->ifname,
&net->mac,
virDomainNetGetActualDirectDev(net),
virDomainNetGetActualDirectMode(net),
virDomainNetGetActualVlan(net),
def->uuid,
virDomainNetGetActualVirtPortProfile(net),
&res_ifname,
vmop, cfg->stateDir,
tapfd, tapfdSize,
macvlan_create_flags) < 0)
goto cleanup;
virDomainAuditNetDevice(def, net, res_ifname, true);
VIR_FREE(net->ifname);
net->ifname = res_ifname;
ret = 0;
cleanup:
if (ret < 0) {
while (tapfdSize--)
VIR_FORCE_CLOSE(tapfd[tapfdSize]);
}
return ret;
}
/**
* qemuCreateInBridgePortWithHelper:
* @cfg: the configuration object in which the helper name is looked up
* @brname: the bridge name
* @ifname: the returned interface name
* @macaddr: the returned MAC address
* @tapfd: file descriptor return value for the new tap device
* @flags: OR of virNetDevTapCreateFlags:
* VIR_NETDEV_TAP_CREATE_VNET_HDR
* - Enable IFF_VNET_HDR on the tap device
*
* This function creates a new tap device on a bridge using an external
* helper. The final name for the bridge will be stored in @ifname.
*
* Returns 0 in case of success or -1 on failure
*/
static int
qemuCreateInBridgePortWithHelper(virQEMUDriverConfigPtr cfg,
const char *brname,
char **ifname,
int *tapfd,
unsigned int flags)
{
virCommandPtr cmd;
char *errbuf = NULL, *cmdstr = NULL;
int pair[2] = { -1, -1 };
if ((flags & ~VIR_NETDEV_TAP_CREATE_VNET_HDR) != VIR_NETDEV_TAP_CREATE_IFUP)
return -1;
if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair) < 0) {
virReportSystemError(errno, "%s", _("failed to create socket"));
return -1;
}
if (!virFileIsExecutable(cfg->bridgeHelperName)) {
virReportSystemError(errno, _("'%s' is not a suitable bridge helper"),
cfg->bridgeHelperName);
return -1;
}
cmd = virCommandNew(cfg->bridgeHelperName);
if (flags & VIR_NETDEV_TAP_CREATE_VNET_HDR)
virCommandAddArgFormat(cmd, "--use-vnet");
virCommandAddArgFormat(cmd, "--br=%s", brname);
virCommandAddArgFormat(cmd, "--fd=%d", pair[1]);
virCommandSetErrorBuffer(cmd, &errbuf);
virCommandDoAsyncIO(cmd);
virCommandPassFD(cmd, pair[1],
VIR_COMMAND_PASS_FD_CLOSE_PARENT);
virCommandClearCaps(cmd);
#ifdef CAP_NET_ADMIN
virCommandAllowCap(cmd, CAP_NET_ADMIN);
#endif
if (virCommandRunAsync(cmd, NULL) < 0) {
*tapfd = -1;
goto cleanup;
}
do {
*tapfd = virSocketRecvFD(pair[0], 0);
} while (*tapfd < 0 && errno == EINTR);
if (*tapfd < 0) {
char *errstr = NULL;
qemu: use line breaks in command line args written to log The QEMU command line arguments are very long and currently all written on a single line to /var/log/libvirt/qemu/$GUEST.log. This introduces logic to add line breaks after every env variable and "-" optional argument, and every positional argument. This will create a clearer log file, which will in turn present better in bug reports when people cut + paste from the log into a bug comment. An example log file entry now looks like this: 2018-12-14 12:57:03.677+0000: starting up libvirt version: 5.0.0, qemu version: 3.0.0qemu-3.0.0-1.fc29, kernel: 4.19.5-300.fc29.x86_64, hostname: localhost.localdomain LC_ALL=C \ PATH=/usr/local/bin:/usr/local/sbin:/usr/bin:/usr/sbin \ HOME=/home/berrange \ USER=berrange \ LOGNAME=berrange \ QEMU_AUDIO_DRV=none \ /usr/bin/qemu-system-ppc64 \ -name guest=guest,debug-threads=on \ -S \ -object secret,id=masterKey0,format=raw,file=/home/berrange/.config/libvirt/qemu/lib/domain-33-guest/master-key.aes \ -machine pseries-2.10,accel=tcg,usb=off,dump-guest-core=off \ -m 1024 \ -realtime mlock=off \ -smp 1,sockets=1,cores=1,threads=1 \ -uuid c8a74977-ab18-41d0-ae3b-4041c7fffbcd \ -display none \ -no-user-config \ -nodefaults \ -chardev socket,id=charmonitor,fd=23,server,nowait \ -mon chardev=charmonitor,id=monitor,mode=control \ -rtc base=utc \ -no-shutdown \ -boot strict=on \ -device qemu-xhci,id=usb,bus=pci.0,addr=0x1 \ -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x2 \ -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny \ -msg timestamp=on 2018-12-14 12:57:03.730+0000: shutting down, reason=failed Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2018-12-14 12:07:08 +00:00
if (!(cmdstr = virCommandToString(cmd, false)))
goto cleanup;
virCommandAbort(cmd);
if (errbuf && *errbuf)
errstr = g_strdup_printf("\nstderr=%s", errbuf);
virReportError(VIR_ERR_INTERNAL_ERROR,
_("%s: failed to communicate with bridge helper: %s%s"),
cmdstr, g_strerror(errno),
NULLSTR_EMPTY(errstr));
VIR_FREE(errstr);
goto cleanup;
}
if (virNetDevTapGetName(*tapfd, ifname) < 0 ||
virCommandWait(cmd, NULL) < 0) {
VIR_FORCE_CLOSE(*tapfd);
*tapfd = -1;
}
cleanup:
VIR_FREE(cmdstr);
VIR_FREE(errbuf);
virCommandFree(cmd);
VIR_FORCE_CLOSE(pair[0]);
return *tapfd < 0 ? -1 : 0;
}
/* qemuInterfaceEthernetConnect:
* @def: the definition of the VM
* @driver: qemu driver data
* @net: pointer to the VM's interface description
* @tapfd: array of file descriptor return value for the new device
* @tapfdsize: number of file descriptors in @tapfd
*
* Called *only* called if actualType is VIR_DOMAIN_NET_TYPE_ETHERNET
* (i.e. if the connection is made with a tap device)
*/
int
qemuInterfaceEthernetConnect(virDomainDefPtr def,
virQEMUDriverPtr driver,
virDomainNetDefPtr net,
int *tapfd,
size_t tapfdSize)
{
virMacAddr tapmac;
int ret = -1;
unsigned int tap_create_flags = VIR_NETDEV_TAP_CREATE_IFUP;
bool template_ifname = false;
g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(driver);
const char *tunpath = "/dev/net/tun";
const char *auditdev = tunpath;
if (net->backend.tap) {
tunpath = net->backend.tap;
if (!driver->privileged) {
virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
_("cannot use custom tap device in session mode"));
goto cleanup;
}
}
if (qemuInterfaceIsVnetCompatModel(net))
tap_create_flags |= VIR_NETDEV_TAP_CREATE_VNET_HDR;
qemu: support unmanaged target tap dev for <interface type='ethernet'> If managed='no', then the tap device must already exist, and setting of MAC address and online status (IFF_UP) is skipped. NB: we still set IFF_VNET_HDR and IFF_MULTI_QUEUE as appropriate, because those bits must be properly set in the TUNSETIFF we use to set the tap device name of the handle we've opened - if IFF_VNET_HDR has not been set and we set it the request will be honored even when running libvirtd unprivileged; if IFF_MULTI_QUEUE is requested to be different than how it was created, that will result in an error from the kernel. This means that you don't need to pay attention to IFF_VNET_HDR when creating the tap devices, but you *do* need to set IFF_MULTI_QUEUE if you're going to use multiple queues for your tap device. NB2: /dev/vhost-net normally has permissions 600, so it can't be opened by an unprivileged process. This would normally cause a warning message when using a virtio net device from an unprivileged libvirtd. I've found that setting the permissions for /dev/vhost-net permits unprivileged libvirtd to use vhost-net for virtio devices, but have no idea what sort of security implications that has. I haven't changed libvrit's code to avoid *attempting* to open /dev/vhost-net - if you are concerned about the security of opening up permissions of /dev/vhost-net (probably a good idea at least until we ask someone who knows about the code) then add <driver name='qemu'/> to the interface definition and you'll avoid the warning message. Note that virNetDevTapCreate() is the correct function to call in the case of an existing device, because the same ioctl() that creates a new tap device will also open an existing tap device. Resolves: https://bugzilla.redhat.com/1723367 (partially) Signed-off-by: Laine Stump <laine@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2019-08-26 04:24:34 +00:00
if (net->managed_tap == VIR_TRISTATE_BOOL_NO) {
if (!net->ifname) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("target dev must be supplied when managed='no'"));
goto cleanup;
qemu: support unmanaged target tap dev for <interface type='ethernet'> If managed='no', then the tap device must already exist, and setting of MAC address and online status (IFF_UP) is skipped. NB: we still set IFF_VNET_HDR and IFF_MULTI_QUEUE as appropriate, because those bits must be properly set in the TUNSETIFF we use to set the tap device name of the handle we've opened - if IFF_VNET_HDR has not been set and we set it the request will be honored even when running libvirtd unprivileged; if IFF_MULTI_QUEUE is requested to be different than how it was created, that will result in an error from the kernel. This means that you don't need to pay attention to IFF_VNET_HDR when creating the tap devices, but you *do* need to set IFF_MULTI_QUEUE if you're going to use multiple queues for your tap device. NB2: /dev/vhost-net normally has permissions 600, so it can't be opened by an unprivileged process. This would normally cause a warning message when using a virtio net device from an unprivileged libvirtd. I've found that setting the permissions for /dev/vhost-net permits unprivileged libvirtd to use vhost-net for virtio devices, but have no idea what sort of security implications that has. I haven't changed libvrit's code to avoid *attempting* to open /dev/vhost-net - if you are concerned about the security of opening up permissions of /dev/vhost-net (probably a good idea at least until we ask someone who knows about the code) then add <driver name='qemu'/> to the interface definition and you'll avoid the warning message. Note that virNetDevTapCreate() is the correct function to call in the case of an existing device, because the same ioctl() that creates a new tap device will also open an existing tap device. Resolves: https://bugzilla.redhat.com/1723367 (partially) Signed-off-by: Laine Stump <laine@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2019-08-26 04:24:34 +00:00
}
if (virNetDevExists(net->ifname) != 1) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("target managed='no' but specified dev doesn't exist"));
goto cleanup;
}
2019-08-26 17:05:19 +00:00
if (virNetDevMacVLanIsMacvtap(net->ifname)) {
auditdev = net->ifname;
if (virNetDevMacVLanTapOpen(net->ifname, tapfd, tapfdSize) < 0)
goto cleanup;
if (virNetDevMacVLanTapSetup(tapfd, tapfdSize,
qemuInterfaceIsVnetCompatModel(net)) < 0) {
2019-08-26 17:05:19 +00:00
goto cleanup;
}
} else {
if (virNetDevTapCreate(&net->ifname, tunpath, tapfd, tapfdSize,
tap_create_flags) < 0)
goto cleanup;
qemu: support unmanaged target tap dev for <interface type='ethernet'> If managed='no', then the tap device must already exist, and setting of MAC address and online status (IFF_UP) is skipped. NB: we still set IFF_VNET_HDR and IFF_MULTI_QUEUE as appropriate, because those bits must be properly set in the TUNSETIFF we use to set the tap device name of the handle we've opened - if IFF_VNET_HDR has not been set and we set it the request will be honored even when running libvirtd unprivileged; if IFF_MULTI_QUEUE is requested to be different than how it was created, that will result in an error from the kernel. This means that you don't need to pay attention to IFF_VNET_HDR when creating the tap devices, but you *do* need to set IFF_MULTI_QUEUE if you're going to use multiple queues for your tap device. NB2: /dev/vhost-net normally has permissions 600, so it can't be opened by an unprivileged process. This would normally cause a warning message when using a virtio net device from an unprivileged libvirtd. I've found that setting the permissions for /dev/vhost-net permits unprivileged libvirtd to use vhost-net for virtio devices, but have no idea what sort of security implications that has. I haven't changed libvrit's code to avoid *attempting* to open /dev/vhost-net - if you are concerned about the security of opening up permissions of /dev/vhost-net (probably a good idea at least until we ask someone who knows about the code) then add <driver name='qemu'/> to the interface definition and you'll avoid the warning message. Note that virNetDevTapCreate() is the correct function to call in the case of an existing device, because the same ioctl() that creates a new tap device will also open an existing tap device. Resolves: https://bugzilla.redhat.com/1723367 (partially) Signed-off-by: Laine Stump <laine@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2019-08-26 04:24:34 +00:00
}
} else {
if (!net->ifname)
qemu: support unmanaged target tap dev for <interface type='ethernet'> If managed='no', then the tap device must already exist, and setting of MAC address and online status (IFF_UP) is skipped. NB: we still set IFF_VNET_HDR and IFF_MULTI_QUEUE as appropriate, because those bits must be properly set in the TUNSETIFF we use to set the tap device name of the handle we've opened - if IFF_VNET_HDR has not been set and we set it the request will be honored even when running libvirtd unprivileged; if IFF_MULTI_QUEUE is requested to be different than how it was created, that will result in an error from the kernel. This means that you don't need to pay attention to IFF_VNET_HDR when creating the tap devices, but you *do* need to set IFF_MULTI_QUEUE if you're going to use multiple queues for your tap device. NB2: /dev/vhost-net normally has permissions 600, so it can't be opened by an unprivileged process. This would normally cause a warning message when using a virtio net device from an unprivileged libvirtd. I've found that setting the permissions for /dev/vhost-net permits unprivileged libvirtd to use vhost-net for virtio devices, but have no idea what sort of security implications that has. I haven't changed libvrit's code to avoid *attempting* to open /dev/vhost-net - if you are concerned about the security of opening up permissions of /dev/vhost-net (probably a good idea at least until we ask someone who knows about the code) then add <driver name='qemu'/> to the interface definition and you'll avoid the warning message. Note that virNetDevTapCreate() is the correct function to call in the case of an existing device, because the same ioctl() that creates a new tap device will also open an existing tap device. Resolves: https://bugzilla.redhat.com/1723367 (partially) Signed-off-by: Laine Stump <laine@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2019-08-26 04:24:34 +00:00
template_ifname = true;
qemu: support unmanaged target tap dev for <interface type='ethernet'> If managed='no', then the tap device must already exist, and setting of MAC address and online status (IFF_UP) is skipped. NB: we still set IFF_VNET_HDR and IFF_MULTI_QUEUE as appropriate, because those bits must be properly set in the TUNSETIFF we use to set the tap device name of the handle we've opened - if IFF_VNET_HDR has not been set and we set it the request will be honored even when running libvirtd unprivileged; if IFF_MULTI_QUEUE is requested to be different than how it was created, that will result in an error from the kernel. This means that you don't need to pay attention to IFF_VNET_HDR when creating the tap devices, but you *do* need to set IFF_MULTI_QUEUE if you're going to use multiple queues for your tap device. NB2: /dev/vhost-net normally has permissions 600, so it can't be opened by an unprivileged process. This would normally cause a warning message when using a virtio net device from an unprivileged libvirtd. I've found that setting the permissions for /dev/vhost-net permits unprivileged libvirtd to use vhost-net for virtio devices, but have no idea what sort of security implications that has. I haven't changed libvrit's code to avoid *attempting* to open /dev/vhost-net - if you are concerned about the security of opening up permissions of /dev/vhost-net (probably a good idea at least until we ask someone who knows about the code) then add <driver name='qemu'/> to the interface definition and you'll avoid the warning message. Note that virNetDevTapCreate() is the correct function to call in the case of an existing device, because the same ioctl() that creates a new tap device will also open an existing tap device. Resolves: https://bugzilla.redhat.com/1723367 (partially) Signed-off-by: Laine Stump <laine@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2019-08-26 04:24:34 +00:00
if (virNetDevTapCreate(&net->ifname, tunpath, tapfd, tapfdSize,
tap_create_flags) < 0) {
goto cleanup;
}
qemu: support unmanaged target tap dev for <interface type='ethernet'> If managed='no', then the tap device must already exist, and setting of MAC address and online status (IFF_UP) is skipped. NB: we still set IFF_VNET_HDR and IFF_MULTI_QUEUE as appropriate, because those bits must be properly set in the TUNSETIFF we use to set the tap device name of the handle we've opened - if IFF_VNET_HDR has not been set and we set it the request will be honored even when running libvirtd unprivileged; if IFF_MULTI_QUEUE is requested to be different than how it was created, that will result in an error from the kernel. This means that you don't need to pay attention to IFF_VNET_HDR when creating the tap devices, but you *do* need to set IFF_MULTI_QUEUE if you're going to use multiple queues for your tap device. NB2: /dev/vhost-net normally has permissions 600, so it can't be opened by an unprivileged process. This would normally cause a warning message when using a virtio net device from an unprivileged libvirtd. I've found that setting the permissions for /dev/vhost-net permits unprivileged libvirtd to use vhost-net for virtio devices, but have no idea what sort of security implications that has. I haven't changed libvrit's code to avoid *attempting* to open /dev/vhost-net - if you are concerned about the security of opening up permissions of /dev/vhost-net (probably a good idea at least until we ask someone who knows about the code) then add <driver name='qemu'/> to the interface definition and you'll avoid the warning message. Note that virNetDevTapCreate() is the correct function to call in the case of an existing device, because the same ioctl() that creates a new tap device will also open an existing tap device. Resolves: https://bugzilla.redhat.com/1723367 (partially) Signed-off-by: Laine Stump <laine@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2019-08-26 04:24:34 +00:00
/* The tap device's MAC address cannot match the MAC address
* used by the guest. This results in "received packet on
* vnetX with own address as source address" error logs from
* the kernel.
*/
virMacAddrSet(&tapmac, &net->mac);
if (tapmac.addr[0] == 0xFE)
tapmac.addr[0] = 0xFA;
else
tapmac.addr[0] = 0xFE;
qemu: support unmanaged target tap dev for <interface type='ethernet'> If managed='no', then the tap device must already exist, and setting of MAC address and online status (IFF_UP) is skipped. NB: we still set IFF_VNET_HDR and IFF_MULTI_QUEUE as appropriate, because those bits must be properly set in the TUNSETIFF we use to set the tap device name of the handle we've opened - if IFF_VNET_HDR has not been set and we set it the request will be honored even when running libvirtd unprivileged; if IFF_MULTI_QUEUE is requested to be different than how it was created, that will result in an error from the kernel. This means that you don't need to pay attention to IFF_VNET_HDR when creating the tap devices, but you *do* need to set IFF_MULTI_QUEUE if you're going to use multiple queues for your tap device. NB2: /dev/vhost-net normally has permissions 600, so it can't be opened by an unprivileged process. This would normally cause a warning message when using a virtio net device from an unprivileged libvirtd. I've found that setting the permissions for /dev/vhost-net permits unprivileged libvirtd to use vhost-net for virtio devices, but have no idea what sort of security implications that has. I haven't changed libvrit's code to avoid *attempting* to open /dev/vhost-net - if you are concerned about the security of opening up permissions of /dev/vhost-net (probably a good idea at least until we ask someone who knows about the code) then add <driver name='qemu'/> to the interface definition and you'll avoid the warning message. Note that virNetDevTapCreate() is the correct function to call in the case of an existing device, because the same ioctl() that creates a new tap device will also open an existing tap device. Resolves: https://bugzilla.redhat.com/1723367 (partially) Signed-off-by: Laine Stump <laine@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2019-08-26 04:24:34 +00:00
if (virNetDevSetMAC(net->ifname, &tapmac) < 0)
goto cleanup;
if (virNetDevSetOnline(net->ifname, true) < 0)
goto cleanup;
}
if (net->script &&
virNetDevRunEthernetScript(net->ifname, net->script) < 0)
goto cleanup;
if (cfg->macFilter &&
ebtablesAddForwardAllowIn(driver->ebtables,
net->ifname,
&net->mac) < 0)
goto cleanup;
if (net->filter &&
virDomainConfNWFilterInstantiate(def->name, def->uuid, net, false) < 0) {
goto cleanup;
}
virDomainAuditNetDevice(def, net, auditdev, true);
ret = 0;
cleanup:
if (ret < 0) {
size_t i;
virDomainAuditNetDevice(def, net, auditdev, false);
for (i = 0; i < tapfdSize && tapfd[i] >= 0; i++)
VIR_FORCE_CLOSE(tapfd[i]);
if (template_ifname)
VIR_FREE(net->ifname);
}
return ret;
}
/* qemuInterfaceBridgeConnect:
* @def: the definition of the VM
* @driver: qemu driver data
* @net: pointer to the VM's interface description
* @tapfd: array of file descriptor return value for the new device
* @tapfdsize: number of file descriptors in @tapfd
*
* Called *only* called if actualType is VIR_DOMAIN_NET_TYPE_NETWORK or
* VIR_DOMAIN_NET_TYPE_BRIDGE (i.e. if the connection is made with a tap
* device connecting to a bridge device)
*/
int
qemuInterfaceBridgeConnect(virDomainDefPtr def,
virQEMUDriverPtr driver,
virDomainNetDefPtr net,
int *tapfd,
size_t *tapfdSize)
{
const char *brname;
int ret = -1;
unsigned int tap_create_flags = VIR_NETDEV_TAP_CREATE_IFUP;
bool template_ifname = false;
g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(driver);
const char *tunpath = "/dev/net/tun";
if (net->backend.tap) {
tunpath = net->backend.tap;
if (!driver->privileged) {
virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
_("cannot use custom tap device in session mode"));
goto cleanup;
}
}
if (!(brname = virDomainNetGetActualBridgeName(net))) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("Missing bridge name"));
goto cleanup;
}
if (!net->ifname)
template_ifname = true;
if (qemuInterfaceIsVnetCompatModel(net))
tap_create_flags |= VIR_NETDEV_TAP_CREATE_VNET_HDR;
if (driver->privileged) {
if (virNetDevTapCreateInBridgePort(brname, &net->ifname, &net->mac,
def->uuid, tunpath, tapfd, *tapfdSize,
virDomainNetGetActualVirtPortProfile(net),
virDomainNetGetActualVlan(net),
virDomainNetGetActualPortOptionsIsolated(net),
net->coalesce, 0, NULL,
tap_create_flags) < 0) {
virDomainAuditNetDevice(def, net, tunpath, false);
goto cleanup;
}
if (virDomainNetGetActualBridgeMACTableManager(net)
== VIR_NETWORK_BRIDGE_MAC_TABLE_MANAGER_LIBVIRT) {
/* libvirt is managing the FDB of the bridge this device
* is attaching to, so we need to turn off learning and
* unicast_flood on the device to prevent the kernel from
2017-04-22 19:06:20 +00:00
* adding any FDB entries for it. We will add an fdb
* entry ourselves (during qemuInterfaceStartDevices(),
* using the MAC address from the interface config.
*/
if (virNetDevBridgePortSetLearning(brname, net->ifname, false) < 0)
goto cleanup;
if (virNetDevBridgePortSetUnicastFlood(brname, net->ifname, false) < 0)
goto cleanup;
}
} else {
if (qemuCreateInBridgePortWithHelper(cfg, brname,
&net->ifname,
tapfd, tap_create_flags) < 0) {
virDomainAuditNetDevice(def, net, tunpath, false);
goto cleanup;
}
/* qemuCreateInBridgePortWithHelper can only create a single FD */
if (*tapfdSize > 1) {
VIR_WARN("Ignoring multiqueue network request");
*tapfdSize = 1;
}
}
virDomainAuditNetDevice(def, net, tunpath, true);
if (cfg->macFilter &&
ebtablesAddForwardAllowIn(driver->ebtables,
net->ifname,
&net->mac) < 0)
goto cleanup;
if (net->filter &&
virDomainConfNWFilterInstantiate(def->name, def->uuid, net, false) < 0) {
goto cleanup;
}
ret = 0;
cleanup:
if (ret < 0) {
size_t i;
for (i = 0; i < *tapfdSize && tapfd[i] >= 0; i++)
VIR_FORCE_CLOSE(tapfd[i]);
if (template_ifname)
VIR_FREE(net->ifname);
}
return ret;
}
/* qemuInterfaceVDPAConnect:
* @net: pointer to the VM's interface description
*
* returns: file descriptor of the vdpa device
*
* Called *only* called if actualType is VIR_DOMAIN_NET_TYPE_VDPA
*/
int
qemuInterfaceVDPAConnect(virDomainNetDefPtr net)
{
int fd;
if ((fd = open(net->data.vdpa.devicepath, O_RDWR)) < 0) {
virReportSystemError(errno,
_("Unable to open '%s' for vdpa device"),
net->data.vdpa.devicepath);
return -1;
}
return fd;
}
/*
* Returns: -1 on error, 0 if slirp isn't available, 1 on succcess
*/
int
qemuInterfacePrepareSlirp(virQEMUDriverPtr driver,
virDomainNetDefPtr net,
qemuSlirpPtr *slirpret)
{
g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(driver);
g_autoptr(qemuSlirp) slirp = NULL;
size_t i;
if (!cfg->slirpHelperName ||
!virFileExists(cfg->slirpHelperName))
return 0; /* fallback to builtin slirp impl */
if (!(slirp = qemuSlirpNewForHelper(cfg->slirpHelperName)))
return -1;
for (i = 0; i < net->guestIP.nips; i++) {
const virNetDevIPAddr *ip = net->guestIP.ips[i];
if (VIR_SOCKET_ADDR_IS_FAMILY(&ip->address, AF_INET) &&
!qemuSlirpHasFeature(slirp, QEMU_SLIRP_FEATURE_IPV4))
return 0;
if (VIR_SOCKET_ADDR_IS_FAMILY(&ip->address, AF_INET6) &&
!qemuSlirpHasFeature(slirp, QEMU_SLIRP_FEATURE_IPV6))
return 0;
}
*slirpret = g_steal_pointer(&slirp);
return 1;
}
/**
* qemuInterfaceOpenVhostNet:
* @def: domain definition
* @net: network definition
* @qemuCaps: qemu binary capabilities
* @vhostfd: array of opened vhost-net device
* @vhostfdSize: number of file descriptors in @vhostfd array
*
* Open vhost-net, multiple times - if requested.
* In case, no vhost-net is needed, @vhostfdSize is set to 0
* and 0 is returned.
*
* Returns: 0 on success
* -1 on failure
*/
int
qemuInterfaceOpenVhostNet(virDomainDefPtr def,
virDomainNetDefPtr net,
int *vhostfd,
size_t *vhostfdSize)
{
size_t i;
const char *vhostnet_path = net->backend.vhost;
if (!vhostnet_path)
vhostnet_path = "/dev/vhost-net";
/* If running a plain QEMU guest, or
* if the config says explicitly to not use vhost, return now */
if (def->virtType != VIR_DOMAIN_VIRT_KVM ||
net->driver.virtio.name == VIR_DOMAIN_NET_BACKEND_TYPE_QEMU) {
*vhostfdSize = 0;
return 0;
}
/* If qemu doesn't support vhost-net mode (including the -netdev and
* -device command options), don't try to open the device.
*/
if (!qemuDomainSupportsNicdev(def, net)) {
if (net->driver.virtio.name == VIR_DOMAIN_NET_BACKEND_TYPE_VHOST) {
virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
"%s", _("vhost-net is not supported with "
"this QEMU binary"));
return -1;
}
*vhostfdSize = 0;
return 0;
}
/* If the nic model isn't virtio, don't try to open. */
if (!virDomainNetIsVirtioModel(net)) {
if (net->driver.virtio.name == VIR_DOMAIN_NET_BACKEND_TYPE_VHOST) {
virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
"%s", _("vhost-net is only supported for "
"virtio network interfaces"));
return -1;
}
*vhostfdSize = 0;
return 0;
}
for (i = 0; i < *vhostfdSize; i++) {
vhostfd[i] = open(vhostnet_path, O_RDWR);
/* If the config says explicitly to use vhost and we couldn't open it,
* report an error.
*/
if (vhostfd[i] < 0) {
virDomainAuditNetDevice(def, net, vhostnet_path, false);
if (net->driver.virtio.name == VIR_DOMAIN_NET_BACKEND_TYPE_VHOST) {
virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
"%s", _("vhost-net was requested for an interface, "
"but is unavailable"));
goto error;
}
VIR_WARN("Unable to open vhost-net. Opened so far %zu, requested %zu",
i, *vhostfdSize);
*vhostfdSize = i;
break;
}
}
virDomainAuditNetDevice(def, net, vhostnet_path, *vhostfdSize);
return 0;
error:
while (i--)
VIR_FORCE_CLOSE(vhostfd[i]);
return -1;
}