Enable capability to add and remove vlan filters for a standard linux bridge using netlink. New function virNetlinkBridgeVlanFilterSet can be used to add or remove a vlan filter to a given bridge interface. Signed-off-by: Leigh Brown <leigh(a)solinno.co.uk&gt; --- src/util/virnetlink.c | 66 +++++++++++++++++++++++++++++++++++++++++++ src/util/virnetlink.h | 7 +++++ 2 files changed, 73 insertions(+) diff --git a/src/util/virnetlink.c b/src/util/virnetlink.c index 24cd69a385..206646d9d7 100644 --- a/src/util/virnetlink.c +++ b/src/util/virnetlink.c @@ -701,6 +701,72 @@ virNetlinkDelLink(const char *ifname, virNetlinkTalkFallback fallback) return 0; } +/** + * virNetlinkBridgeVlanFilterSet: + * + * @ifname: name of the link + * @cmd: netlink command, either RTM_SETLINK or RTM_DELLINK + * @flags: flags to use when adding the vlan filter + * @vid: vlan id to add or remove + * @error: netlink error code + * + * Add or remove a vlan filter from an interface associated with a + * bridge. + * + * Returns 0 on success, -1 on error. Additionally, if the @error is + * non-zero, then a netlink failure occurred, but no error message + * is generated leaving it up to the caller to handle the condition. + */ +int +virNetlinkBridgeVlanFilterSet(const char *ifname, + int cmd, + const unsigned short flags, + const short vid, + int *error) +{ + struct ifinfomsg ifm = { .ifi_family = PF_BRIDGE }; + struct bridge_vlan_info vinfo = { .flags = flags, .vid = vid }; + struct nlattr *afspec = NULL; + g_autoptr(virNetlinkMsg) nl_msg = NULL; + g_autofree struct nlmsghdr *resp = NULL; + unsigned int resp_len = 0; + + *error = 0; + + if (vid < 1 || vid > 4095) { + virReportError(ERANGE, _("vlanid out of range: %1$d"), vid); + return -1; + } + + if (!(cmd == RTM_SETLINK || cmd == RTM_DELLINK)) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("Invalid vlan filter command %1$d"), cmd); + return -1; + } + + if (virNetDevGetIndex(ifname, &ifm.ifi_index) < 0) + return -1; + + nl_msg = virNetlinkMsgNew(cmd, NLM_F_REQUEST); + + NETLINK_MSG_APPEND(nl_msg, sizeof(ifm), &ifm); + + NETLINK_MSG_NEST_START(nl_msg, afspec, IFLA_AF_SPEC); + NETLINK_MSG_PUT(nl_msg, IFLA_BRIDGE_VLAN_INFO, sizeof(vinfo), &vinfo); + NETLINK_MSG_NEST_END(nl_msg, afspec); + + if (virNetlinkTalk(ifname, nl_msg, 0, 0, &resp, &resp_len, error, NULL) < 0) + return -1; + + if (resp->nlmsg_type != NLMSG_ERROR && resp->nlmsg_type != NLMSG_DONE) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("malformed netlink response message")); + return -1; + } + + return 0; +} + /** * virNetlinkGetNeighbor: * diff --git a/src/util/virnetlink.h b/src/util/virnetlink.h index 75192f645f..327fb426a1 100644 --- a/src/util/virnetlink.h +++ b/src/util/virnetlink.h @@ -25,6 +25,7 @@ #if defined(WITH_LIBNL) # include <netlink/msg.h> +# include <linux/if_bridge.h> typedef struct nl_msg virNetlinkMsg; G_DEFINE_AUTOPTR_CLEANUP_FUNC(virNetlinkMsg, nlmsg_free); @@ -76,6 +77,12 @@ typedef int (*virNetlinkTalkFallback)(const char *ifname); int virNetlinkDelLink(const char *ifname, virNetlinkTalkFallback fallback); +int virNetlinkBridgeVlanFilterSet(const char *ifname, + int cmd, + const unsigned short flags, + const short vid, + int *error); + int virNetlinkGetErrorCode(struct nlmsghdr *resp, unsigned int recvbuflen); int virNetlinkDumpLink(const char *ifname, int ifindex, -- 2.39.5

Add virNetDevBridgeSetupVlans function to configures a bridge interface using the passed virNetDevVlan struct. Add virVlan parameter to the Linux version of virNetDevBridgeAddPort and call virNetDevBridgeSetupVlans to set up the required vlan configuration. Update callers of virNetDevBridgeAddPort to pass NULL for now. Signed-off-by: Leigh Brown <leigh(a)solinno.co.uk&gt; --- src/lxc/lxc_process.c | 2 +- src/util/virnetdevbridge.c | 75 ++++++++++++++++++++++++++++++++++++-- src/util/virnetdevbridge.h | 4 +- src/util/virnetdevtap.c | 2 +- 4 files changed, 76 insertions(+), 7 deletions(-) diff --git a/src/lxc/lxc_process.c b/src/lxc/lxc_process.c index c2982244f0..7c760cec40 100644 --- a/src/lxc/lxc_process.c +++ b/src/lxc/lxc_process.c @@ -289,7 +289,7 @@ virLXCProcessSetupInterfaceTap(virDomainDef *vm, vport, virDomainNetGetActualVlan(net)) < 0) return NULL; } else { - if (virNetDevBridgeAddPort(brname, parentVeth) < 0) + if (virNetDevBridgeAddPort(brname, parentVeth, NULL) < 0) return NULL; if (virDomainNetGetActualPortOptionsIsolated(net) == VIR_TRISTATE_BOOL_YES && diff --git a/src/util/virnetdevbridge.c b/src/util/virnetdevbridge.c index 5fd88f3195..80f028e9b7 100644 --- a/src/util/virnetdevbridge.c +++ b/src/util/virnetdevbridge.c @@ -313,6 +313,65 @@ virNetDevBridgePortSetIsolated(const char *brname, return virNetDevBridgePortSet(brname, ifname, "isolated", enable ? 1 : 0); } +static int +virNetDevBridgeSetupVlans(const char *ifname, const virNetDevVlan *virtVlan) +{ + int error = 0; + unsigned short flags; + + if (!virtVlan || !virtVlan->nTags) + return 0; + + // The interface will have been automatically added to vlan 1, so remove it + if (virNetlinkBridgeVlanFilterSet(ifname, RTM_DELLINK, 0, 1, &error) < 0) + goto err_delete; + + // If trunk mode, add the native VLAN then add the others, if any + if (virtVlan->trunk) { + size_t i; + + if (virtVlan->nativeTag) { + flags = BRIDGE_VLAN_INFO_PVID; + if (virtVlan->nativeMode == VIR_NATIVE_VLAN_MODE_UNTAGGED || + virtVlan->nativeMode == VIR_NATIVE_VLAN_MODE_DEFAULT) + flags |= BRIDGE_VLAN_INFO_UNTAGGED; + + if (virNetlinkBridgeVlanFilterSet(ifname, RTM_SETLINK, flags, + virtVlan->nativeTag, &error) < 0) + goto err_add; + } + + for (i = 0; i < virtVlan->nTags; i++) { + if (virtVlan->tag[i] != virtVlan->nativeTag) + if (virNetlinkBridgeVlanFilterSet(ifname, RTM_SETLINK, 0, + virtVlan->tag[i], &error) < 0) + goto err_add; + } + } else { + // In native mode, add the single VLAN as pvid untagged + flags = BRIDGE_VLAN_INFO_PVID | BRIDGE_VLAN_INFO_UNTAGGED; + if (virNetlinkBridgeVlanFilterSet(ifname, RTM_SETLINK, flags, + virtVlan->tag[0], &error) < 0) + goto err_add; + } + + return 0; + + err_add: + if (error != 0) + virReportSystemError(-error, + _("error adding vlan filter to interface %1$s"), + ifname); + return -1; + + err_delete: + if (error != 0) + virReportSystemError(-error, + _("error removing vlan filter from interface %1$s"), + ifname); + return -1; +} + #else int @@ -593,7 +652,8 @@ int virNetDevBridgeDelete(const char *brname G_GNUC_UNUSED) */ #if defined(WITH_STRUCT_IFREQ) && defined(SIOCBRADDIF) int virNetDevBridgeAddPort(const char *brname, - const char *ifname) + const char *ifname, + const virNetDevVlan *virtVlan) { struct ifreq ifr; VIR_AUTOCLOSE fd = -1; @@ -613,14 +673,20 @@ int virNetDevBridgeAddPort(const char *brname, return -1; } - return 0; + return virNetDevBridgeSetupVlans(ifname, virtVlan); } #elif defined(WITH_BSD_BRIDGE_MGMT) int virNetDevBridgeAddPort(const char *brname, - const char *ifname) + const char *ifname, + const virNetDevVlan *virtVlan) { struct ifbreq req = { 0 }; + if (virtVlan) { + virReportSystemError(ENOSYS, "%s", _("Not supported on this platform")); + return -1; + } + if (virStrcpyStatic(req.ifbr_ifsname, ifname) < 0) { virReportSystemError(ERANGE, _("Network interface name '%1$s' is too long"), @@ -638,7 +704,8 @@ int virNetDevBridgeAddPort(const char *brname, } #else int virNetDevBridgeAddPort(const char *brname, - const char *ifname) + const char *ifname, + const virNetDevVlan *virtVlan) { virReportSystemError(ENOSYS, _("Unable to add bridge %1$s port %2$s"), brname, ifname); diff --git a/src/util/virnetdevbridge.h b/src/util/virnetdevbridge.h index db4099bf0b..5f51656abe 100644 --- a/src/util/virnetdevbridge.h +++ b/src/util/virnetdevbridge.h @@ -20,6 +20,7 @@ #include "internal.h" #include "virmacaddr.h" +#include "virnetdevvlan.h" int virNetDevBridgeCreate(const char *brname, const virMacAddr *mac) @@ -28,7 +29,8 @@ int virNetDevBridgeDelete(const char *brname) ATTRIBUTE_NONNULL(1) G_GNUC_WARN_UNUSED_RESULT; int virNetDevBridgeAddPort(const char *brname, - const char *ifname) + const char *ifname, + const virNetDevVlan *virtVlan) ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) G_GNUC_WARN_UNUSED_RESULT; int virNetDevBridgeRemovePort(const char *brname, diff --git a/src/util/virnetdevtap.c b/src/util/virnetdevtap.c index 2701ba6dfc..a9573eb8e1 100644 --- a/src/util/virnetdevtap.c +++ b/src/util/virnetdevtap.c @@ -483,7 +483,7 @@ virNetDevTapAttachBridge(const char *tapname, return -1; } } else { - if (virNetDevBridgeAddPort(brname, tapname) < 0) + if (virNetDevBridgeAddPort(brname, tapname, NULL) < 0) return -1; if (isolatedPort == VIR_TRISTATE_BOOL_YES && -- 2.39.5

Hello, On 2025-01-08 07:26, Laine Stump wrote: I will update. I will update. I've not used OVS but I read the documentation and I believe the behaviour is the same. Thanks, I will make the changes and send an updated version. > Assuming those changes: > > Reviewed-by: Laine Stump <laine(a)redhat.com&gt; > >> +} >> + >> #else >> int >> @@ -593,7 +652,8 @@ int virNetDevBridgeDelete(const char *brname >> G_GNUC_UNUSED) >> */ >> #if defined(WITH_STRUCT_IFREQ) && defined(SIOCBRADDIF) >> int virNetDevBridgeAddPort(const char *brname, >> - const char *ifname) >> + const char *ifname, >> + const virNetDevVlan *virtVlan) >> { >> struct ifreq ifr; >> VIR_AUTOCLOSE fd = -1; >> @@ -613,14 +673,20 @@ int virNetDevBridgeAddPort(const char *brname, >> return -1; >> } >> - return 0; >> + return virNetDevBridgeSetupVlans(ifname, virtVlan); >> } >> #elif defined(WITH_BSD_BRIDGE_MGMT) >> int virNetDevBridgeAddPort(const char *brname, >> - const char *ifname) >> + const char *ifname, >> + const virNetDevVlan *virtVlan) >> { >> struct ifbreq req = { 0 }; >> + if (virtVlan) { >> + virReportSystemError(ENOSYS, "%s", _("Not supported on this >> platform")); >> + return -1; >> + } >> + >> if (virStrcpyStatic(req.ifbr_ifsname, ifname) < 0) { >> virReportSystemError(ERANGE, >> _("Network interface name '%1$s' is too >> long"), >> @@ -638,7 +704,8 @@ int virNetDevBridgeAddPort(const char *brname, >> } >> #else >> int virNetDevBridgeAddPort(const char *brname, >> - const char *ifname) >> + const char *ifname, >> + const virNetDevVlan *virtVlan) >> { >> virReportSystemError(ENOSYS, >> _("Unable to add bridge %1$s port %2$s"), >> brname, ifname); >> diff --git a/src/util/virnetdevbridge.h b/src/util/virnetdevbridge.h >> index db4099bf0b..5f51656abe 100644 >> --- a/src/util/virnetdevbridge.h >> +++ b/src/util/virnetdevbridge.h >> @@ -20,6 +20,7 @@ >> #include "internal.h" >> #include "virmacaddr.h" >> +#include "virnetdevvlan.h" >> int virNetDevBridgeCreate(const char *brname, >> const virMacAddr *mac) >> @@ -28,7 +29,8 @@ int virNetDevBridgeDelete(const char *brname) >> ATTRIBUTE_NONNULL(1) G_GNUC_WARN_UNUSED_RESULT; >> int virNetDevBridgeAddPort(const char *brname, >> - const char *ifname) >> + const char *ifname, >> + const virNetDevVlan *virtVlan) >> ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) >> G_GNUC_WARN_UNUSED_RESULT; >> int virNetDevBridgeRemovePort(const char *brname, >> diff --git a/src/util/virnetdevtap.c b/src/util/virnetdevtap.c >> index 2701ba6dfc..a9573eb8e1 100644 >> --- a/src/util/virnetdevtap.c >> +++ b/src/util/virnetdevtap.c >> @@ -483,7 +483,7 @@ virNetDevTapAttachBridge(const char *tapname, >> return -1; >> } >> } else { >> - if (virNetDevBridgeAddPort(brname, tapname) < 0) >> + if (virNetDevBridgeAddPort(brname, tapname, NULL) < 0) >> return -1; >> if (isolatedPort == VIR_TRISTATE_BOOL_YES &&

Adjust domain and network validation to permit standard linux bridges to allow vlan configuration. Update calls to virNetDevBridgeAddPort to pass the vlan configuration. Signed-off-by: Leigh Brown <leigh(a)solinno.co.uk&gt; --- src/conf/domain_validate.c | 3 ++- src/lxc/lxc_process.c | 3 ++- src/network/bridge_driver.c | 13 ++++++++----- src/util/virnetdevtap.c | 2 +- 4 files changed, 13 insertions(+), 8 deletions(-) diff --git a/src/conf/domain_validate.c b/src/conf/domain_validate.c index 1034bb57f5..c7a79a0277 100644 --- a/src/conf/domain_validate.c +++ b/src/conf/domain_validate.c @@ -2077,7 +2077,8 @@ virDomainActualNetDefValidate(const virDomainNetDef *net) (actualType == VIR_DOMAIN_NET_TYPE_DIRECT && virDomainNetGetActualDirectMode(net) == VIR_NETDEV_MACVLAN_MODE_PASSTHRU) || (actualType == VIR_DOMAIN_NET_TYPE_BRIDGE && - vport && vport->virtPortType == VIR_NETDEV_VPORT_PROFILE_OPENVSWITCH))) { + vport && vport->virtPortType == VIR_NETDEV_VPORT_PROFILE_OPENVSWITCH) || + (actualType == VIR_DOMAIN_NET_TYPE_BRIDGE && !vport))) { virReportError(VIR_ERR_CONFIG_UNSUPPORTED, _("interface %1$s - vlan tag not supported for this connection type"), macstr); diff --git a/src/lxc/lxc_process.c b/src/lxc/lxc_process.c index 7c760cec40..c427b38605 100644 --- a/src/lxc/lxc_process.c +++ b/src/lxc/lxc_process.c @@ -289,7 +289,8 @@ virLXCProcessSetupInterfaceTap(virDomainDef *vm, vport, virDomainNetGetActualVlan(net)) < 0) return NULL; } else { - if (virNetDevBridgeAddPort(brname, parentVeth, NULL) < 0) + if (virNetDevBridgeAddPort(brname, parentVeth, + virDomainNetGetActualVlan(net)) < 0) return NULL; if (virDomainNetGetActualPortOptionsIsolated(net) == VIR_TRISTATE_BOOL_YES && diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c index ce793c12ef..8f47ef2574 100644 --- a/src/network/bridge_driver.c +++ b/src/network/bridge_driver.c @@ -2999,7 +2999,8 @@ networkValidate(virNetworkDriverState *driver, /* The only type of networks that currently support transparent * vlan configuration are those using hostdev sr-iov devices from - * a pool, and those using an Open vSwitch bridge. + * a pool, those using an Open vSwitch bridge, and standard linux + * bridges. */ vlanAllowed = (def->forward.type == VIR_NETWORK_FORWARD_HOSTDEV || @@ -3007,15 +3008,17 @@ networkValidate(virNetworkDriverState *driver, (def->forward.type == VIR_NETWORK_FORWARD_BRIDGE && def->virtPortProfile && def->virtPortProfile->virtPortType - == VIR_NETDEV_VPORT_PROFILE_OPENVSWITCH)); + == VIR_NETDEV_VPORT_PROFILE_OPENVSWITCH) || + (def->forward.type == VIR_NETWORK_FORWARD_BRIDGE && + !def->virtPortProfile)); vlanUsed = def->vlan.nTags > 0; for (i = 0; i < def->nPortGroups; i++) { if (vlanUsed || def->portGroups[i].vlan.nTags > 0) { /* anyone using this portgroup will get a vlan tag. Verify - * that they will also be using an openvswitch connection, - * as that is the only type of network that currently - * supports a vlan tag. + * that they will also be using an openvswitch connection + * or a standard linux bridge as they are the only types of + * network that currently support a vlan tag. */ if (def->portGroups[i].virtPortProfile) { if (def->forward.type != VIR_NETWORK_FORWARD_BRIDGE || diff --git a/src/util/virnetdevtap.c b/src/util/virnetdevtap.c index a9573eb8e1..1dc77f0f5c 100644 --- a/src/util/virnetdevtap.c +++ b/src/util/virnetdevtap.c @@ -483,7 +483,7 @@ virNetDevTapAttachBridge(const char *tapname, return -1; } } else { - if (virNetDevBridgeAddPort(brname, tapname, NULL) < 0) + if (virNetDevBridgeAddPort(brname, tapname, virtVlan) < 0) return -1; if (isolatedPort == VIR_TRISTATE_BOOL_YES && -- 2.39.5

Update domain XML and network XML documentation to describe how standard linux bridges support the VLAN configuration. Signed-off-by: Leigh Brown <leigh(a)solinno.co.uk&gt; --- docs/formatdomain.rst | 37 +++++++++++++++++----------------- docs/formatnetwork.rst | 45 +++++++++++++++++++++--------------------- 2 files changed, 42 insertions(+), 40 deletions(-) diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst index 8d787ef59a..90b025508a 100644 --- a/docs/formatdomain.rst +++ b/docs/formatdomain.rst @@ -6039,28 +6039,29 @@ VLAN tags to apply to the guest's network traffic :since:`Since 0.10.0`. Network connections that support guest-transparent VLAN tagging include ``type='bridge'`` interfaces connected to an Open vSwitch bridge, SRIOV -Virtual Functions (VF) used via ``type='hostdev'`` (direct device assignment) -and, :since:`since 1.3.5`, SRIOV VFs used via ``type='direct'`` with -``mode='passthrough'`` (macvtap "passthru" mode). All other -connection types, including standard linux bridges and libvirt's own virtual +Virtual Functions (VF) used via ``type='hostdev'`` (direct device assignment), +:since:`since 1.3.5`, SRIOV VFs used via ``type='direct'`` with +``mode='passthrough'`` (macvtap "passthru" mode) and, :since:`since 11.0.0` +standard linux bridges. Other connection types, including libvirt's own virtual networks, **do not** support it. 802.1Qbh (vn-link) and 802.1Qbg (VEPA) switches provide their own way (outside of libvirt) to tag guest traffic onto a specific VLAN. Each tag is given in a separate ``<tag>`` subelement of ``<vlan>`` (for example: ``<tag id='42'/>``). For VLAN trunking of multiple tags (which is -supported only on Open vSwitch connections), multiple ``<tag>`` subelements can -be specified, which implies that the user wants to do VLAN trunking on the -interface for all the specified tags. In the case that VLAN trunking of a single -tag is desired, the optional attribute ``trunk='yes'`` can be added to the -toplevel ``<vlan>`` element to differentiate trunking of a single tag from -normal tagging. - -For network connections using Open vSwitch it is also possible to configure -'native-tagged' and 'native-untagged' VLAN modes :since:`Since 1.1.0`. This is -done with the optional ``nativeMode`` attribute on the ``<tag>`` subelement: -``nativeMode`` may be set to 'tagged' or 'untagged'. The ``id`` attribute of the -``<tag>`` subelement containing ``nativeMode`` sets which VLAN is considered to -be the "native" VLAN for this interface, and the ``nativeMode`` attribute -determines whether or not traffic for that VLAN will be tagged. +supported on Open vSwitch connections and standard linux bridges), multiple +``<tag>`` subelements can be specified, which implies that the user wants to do +VLAN trunking on the interface for all the specified tags. In the case that VLAN +trunking of a single tag is desired, the optional attribute ``trunk='yes'`` can +be added to the toplevel ``<vlan>`` element to differentiate trunking of a +single tag from normal tagging. + +For network connections using Open vSwitch and standard linux bridges it is also +possible to configure 'native-tagged' and 'native-untagged' VLAN modes +:since:`Since 1.1.0`. This is done with the optional ``nativeMode`` attribute on +the ``<tag>`` subelement: ``nativeMode`` may be set to 'tagged' or 'untagged'. +The ``id`` attribute of the ``<tag>`` subelement containing ``nativeMode`` sets +which VLAN is considered to be the "native" VLAN for this interface, and the +``nativeMode`` attribute determines whether or not traffic for that VLAN will be +tagged. Isolating guests' network traffic from each other diff --git a/docs/formatnetwork.rst b/docs/formatnetwork.rst index 9b4ecbf31d..053fe6ad56 100644 --- a/docs/formatnetwork.rst +++ b/docs/formatnetwork.rst @@ -520,28 +520,29 @@ VLAN tags to apply to the guest's network traffic :since:`Since 0.10.0`. Network connections that support guest-transparent VLAN tagging include ``type='bridge'`` interfaces connected to an Open vSwitch bridge, SRIOV -Virtual Functions (VF) used via ``type='hostdev'`` (direct device assignment) -and, :since:`since 1.3.5`, SRIOV VFs used via ``type='direct'`` with -``mode='passthrough'`` (macvtap "passthru" mode). All other -connection types, including standard linux bridges and libvirt's own virtual -networks, **do not** support it. 802.1Qbh (vn-link) and 802.1Qbg (VEPA) switches -provide their own way (outside of libvirt) to tag guest traffic onto a specific -VLAN. Each tag is given in a separate ``<tag>`` subelement of ``<vlan>`` (for -example: ``<tag id='42'/>``). For VLAN trunking of multiple tags (which is -supported only on Open vSwitch connections), multiple ``<tag>`` subelements can -be specified, which implies that the user wants to do VLAN trunking on the -interface for all the specified tags. In the case that VLAN trunking of a single -tag is desired, the optional attribute ``trunk='yes'`` can be added to the -toplevel ``<vlan>`` element to differentiate trunking of a single tag from -normal tagging. - -For network connections using Open vSwitch it is also possible to configure -'native-tagged' and 'native-untagged' VLAN modes :since:`Since 1.1.0`. This is -done with the optional ``nativeMode`` attribute on the ``<tag>`` subelement: -``nativeMode`` may be set to 'tagged' or 'untagged'. The ``id`` attribute of the -``<tag>`` subelement containing ``nativeMode`` sets which VLAN is considered to -be the "native" VLAN for this interface, and the ``nativeMode`` attribute -determines whether or not traffic for that VLAN will be tagged. +Virtual Functions (VF) used via ``type='hostdev'`` (direct device assignment), +:since:`since 1.3.5`, SRIOV VFs used via ``type='direct'`` with +``mode='passthrough'`` (macvtap "passthru" mode) and, :since:`since 11.0.0`, +standard linux bridges. All other connection types, including libvirt's own +virtual networks, **do not** support it. 802.1Qbh (vn-link) and 802.1Qbg (VEPA) +switches provide their own way (outside of libvirt) to tag guest traffic onto a +specific VLAN. Each tag is given in a separate ``<tag>`` subelement of +``<vlan>`` (for example: ``<tag id='42'/>``). For VLAN trunking of multiple +tags (which is supported on Open vSwitch connections and standard linux +bridges), multiple ``<tag>`` subelements can be specified, which implies that +the user wants to do VLAN trunking on the interface for all the specified tags. +In the case that VLAN trunking of a single tag is desired, the optional +attribute ``trunk='yes'`` can be added to the toplevel ``<vlan>`` element to +differentiate trunking of a single tag from normal tagging. + +For network connections using Open vSwitch :since:`since 1.1.10` and standard +linux bridges :since:`since 11.0.0` it is also possible to configure +'native-tagged' and 'native-untagged' VLAN modes. This is done with the optional +``nativeMode`` attribute on the ``<tag>`` subelement: ``nativeMode`` may be set +to 'tagged' or 'untagged'. The ``id`` attribute of the ``<tag>`` subelement +containing ``nativeMode`` sets which VLAN is considered to be the "native" VLAN +for this interface, and the ``nativeMode`` attribute determines whether or not +traffic for that VLAN will be tagged. ``<vlan>`` elements can also be specified in a ``<portgroup>`` element, as well as directly in a domain's ``<interface>`` element. In the case that a vlan tag -- 2.39.5