Re: [Qemu-devel] [Bug 1362755] [NEW] QEmu +2 does not route VLAN tagged packets, that are originated within the Hypervisor itself.

[Vlad Yasevich <vyasevic@redhat.com>]

On 08/28/2014 02:40 PM, Thiago Martins wrote:
> Public bug reported:
> 
> Guys,
> 
> Trusty QEmu 2.0 Hypervisor fails to create a consistent virtual network.
> It does not route tagged VLAN packets.
> 

The have a been a bunch of rather recent changes to the kernel to support
guest VLANs correctly.  The issues have been around TSO/GSO implementation
in the kernel.

Could try disabling TSO/GSO and tx checksums on the vlan devices in the guest
and see if it solves your problem?

If it does, could you try the kernel from
  git://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git
turn the offloads back on and see if the problem is solved?

Thanks
-vlad

> That's it, it is impossible to use Trusty acting as a QEmu 2.0
> Hypervisor (metapakage `ubuntu-virt-server`), to make a basic virtual
> tagged network within itself. QEmu 2.X guest does not route traffic when
> with tagged VLANs!
> 
> So, Trusty QEmu 2.0 Hypervisor cannot be used to host guests acting as
> "firewalls / routers", and it have an easy to reproduce, connectivity
> problem.
> 
> This network problem affects Ubuntu 14.04.1 (Linux-3.13.0-35-generic)
> with QEmu 2.0 (it also affects 14.10, Linux 3.16 - QEmu 2.1).
> 
> I have this very same setup up and running, on about ~100 physical
> servers (others Trusty QEmu 2.0 Hypervisors), and in only a few of them,
> the QEmu Hypervisors dedicated to host "guest acting as routers /
> firewalls", like a "borger gateway" for example, that it does not work
> as expected.
> 
> One interesting thing to note is that, this BUG appear only, and only
> at, the QEmu Hypervisors dedicated to host guests that are used as
> `router / firewalls` (as I said above), others QEmu Hypervisors of my
> network does not suffer from this problem.
> 
> Another interesting point is that it fails to route tagged VLAN packets
> only when these packets are originated from within the Hypervisor
> itself, I mean, packets from both host and other guests (not the
> router/firewall guest itself), suffer from this connectivity problem.
> 
> As a workaroung / fix, Xen-4.4 can be used, instead of QEmu 2.0, as a
> "border hypervisor". So, this proves that there is something wrong with
> QEmu.
> 
> I already tested it with both `openvswitch-switch` and with `bridge-
> utils`, same bad results. So, don't waste your time trying `bridge-
> utils` (optional steps while reproducing it), you can keep OVS bridges
> from original design.
> 
> I think that I'm using the best pratices to build this environment, as
> follows...
> 
> 
> * Topology *
> 
> 
> QEmu 2.0 Hypervisor - (qemu-host-1.domain.com - the "border hypervisor"):
> 
> 1- Physical machine with 3 NICs;
> 2- Minimal Ubuntu 14.04.1 installed and upgraded;
> 3- Packages installed: "ubuntu-virt-server openvswitch-switch rdnssd tcpdump".
> 
> - eth0 connected to the Internet - VLAN tag 10;
> - eth1 connected to the LAN1 - VLAN tag 100;
> - eth2 connected to the LAN2 - VLAN tag 200;
> 
> 
> Guest (guest-fw-1.domain.com - the "border gateway" itself - regular guest acting as a router with iptables/ip6tables):
> 
> 1- Virtual Machine with 3 NICs (VirtIO);
> 2- Minimal Virtual Machine Ubuntu 14.04.1 installed and upgraded;
> 3- Packages installed: "aiccu iptables vlan pv-grub-menu".
> 
> 
> OBS: You'll need `virt-manager` to connect at `qemu-host-1` to install
> `guest-fw-1`. Then, use `guest-fw-1` as a default gateway for your
> (virt-)lab network, including the `qemu-host-1` itself.
> 
> 
> Steps to reproduce
> 
> 
> * Preparing the `qemu-host-1` host:
> 
> - Configure the /etc/network/interfaces with:
> 
> ---
> # The loopback network interface
> auto lo
> iface lo inet loopback
> 
> auto eth0
> iface eth0 inet manual
>         up ip link set $IFACE up
>         down ip link set $IFACE down
> 
> auto eth1
> iface eth1 inet manual
> 	up ip link set dev $IFACE up
> 	down ip link set dev $IFACE down
> 
> auto ovsbr1p1
> iface ovsbr1p1 inet6 auto
> 
> iface ovsbr1p1 inet static
> 	address 192.168.1.10
> 	netmask 24
> 	gateway 192.168.1.1
> 
> auto eth2
> iface eth2 inet manual
> 	up ip link set $IFACE up
> 	down ip link set $IFACE down
> ---
> 
> 
> - Creating the Hypervisor OVS Bridges:
> 
> ovs-vsctl add-br ovsbr0
> ovs-vsctl add-br ovsbr1
> ovs-vsctl add-br ovsbr2
> 
> 
> - Attaching the bridges to the NICs:
> 
> ovs-vsctl add-port ovsbr0 eth0
> ovs-vsctl add-port ovsbr1 eth1
> ovs-vsctl add-port ovsbr2 eth2
> 
> 
> - Creating the OVS internal tagged interface (best practice?), so the QEmu Hypervisor itself can have its own IP (v4 and v6):
> 
> ovs-vsctl add-port ovsbr1 ovsbr1p1 tag=100 -- set interface ovsbr1p1 type=internal
> ovs-vsctl set interface ovsbr1p1 mac=\"32:ac:85:72:ab:fe\"
> 
> 
>  NOTE:
> 
>  * I'm fixing the MAC Address of ovsbr1p1 because I like to use IPv6
> with SLAAC, so, it remain fixed across host reboots.
> 
> 
> - Making Libvirt aware of OVS Bridges:
> 
> Create 3 files, one for each bridge, like this (ovsbr0.xml, ovsbr1.xml
> and ovsbr2.xml):
> 
> --- ovsbr0.xml contents:
> <network>
>  <name>ovsbr0</name>
>  <forward mode='bridge'/>
>  <bridge name='ovsbr0'/>
>  <virtualport type='openvswitch'/>
> </network>
> --- 
> 
> --- ovsbr1.xml contents:
> <network>
>  <name>ovsbr1</name>
>  <forward mode='bridge'/>
>  <bridge name='ovsbr1'/>
>  <virtualport type='openvswitch'/>
> </network>
> --- 
> 
> --- ovsbr2.xml contents:
> <network>
>  <name>ovsbr2</name>
>  <forward mode='bridge'/>
>  <bridge name='ovsbr2'/>
>  <virtualport type='openvswitch'/>
> </network>
> --- 
> 
> 
> Run:
> 
> virsh net-define ovsbr0.xml
> virsh net-define ovsbr1.xml
> virsh net-define ovsbr2.xml
> 
> virsh net-autostart ovsbr0
> virsh net-autostart ovsbr1
> virsh net-autostart ovsbr2
> 
> virsh net-start ovsbr0
> virsh net-start ovsbr1
> virsh net-start ovsbr2
> 
> 
> - Creating the "guest-fw-1.domain.com" (Ubuntu 14.04.1 - Minimum Virtual Machine):
> 
> 1- VM Configuration file (network-only / cutted):
> 
> ---
>     <interface type='network'>
>       <mac address='52:54:00:41:8c:3f'/>
>       <source network='ovsbr0'/>
>       <model type='virtio'/>
>       <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
>     </interface>
>     <interface type='network'>
>       <mac address='52:54:00:27:b2:7d'/>
>       <source network='ovsbr1'/>
>       <model type='virtio'/>
>       <address type='pci' domain='0x0000' bus='0x00' slot='0x09' function='0x0'/>
>     </interface>
>     <interface type='network'>
>       <mac address='52:54:00:ff:35:5c'/>
>       <source network='ovsbr2'/>
>       <model type='virtio'/>
>       <address type='pci' domain='0x0000' bus='0x00' slot='0x0a' function='0x0'/>
>     </interface>
> ---
> 
> 2- Configure "guest-fw-1.domain.com" (the router / firewall guest)
> /etc/network/interfaces file like this:
> 
> ---
> auto vlan10
> iface vlan10 inet static
>         vlan_raw_device eth0
>         address 200.2.1.106
>         netmask 29
>         gateway 200.2.1.105
>         dns-nameserver 8.8.8.8
> 
> auto vlan100
> iface vlan100 inet6 static
>         vlan_raw_device eth1
>         address 2001:129X:2XX:810X::2
>         netmask 64
>         dns-nameserver 2001:4860:4860::8844 2001:4860:4860::8888
> 
> iface vlan100 inet static
>         vlan_raw_device eth1
>         address 192.168.4.1
>         netmask 24
> 
> auto vlan200
> iface vlan200 inet6 static
>         vlan_raw_device eth2
>         address 2001:1291:2de:10::1
>         netmask 64
> 
> iface vlan200 inet static
>         vlan_raw_device eth2
>         address 172.16.0.1
>         netmask 24
> ---
> 
> 3- Enable radvd for your LANs:
> 
> ---
> # SERVERS
> interface vlan100 {
>         AdvSendAdvert on;
>         MinRtrAdvInterval 3;
>         MaxRtrAdvInterval 10;
>         AdvLinkMTU 1500;
>         AdvDefaultPreference high;
>         prefix 2001:1291:200:850a::/64 {
>                 DeprecatePrefix on;
>                 AdvOnLink on;
>                 AdvAutonomous on;
>                 AdvRouterAddr on;
>         };
>         route ::/0 {
>                 RemoveRoute on;
>         };
>         RDNSS 2001:4860:4860::8844 2001:4860:4860::8888 { };
>         DNSSL domain.com.br { };
> };
> # DESKTOPS
> interface vlan200 {
>         AdvSendAdvert on;
>         MinRtrAdvInterval 3;
>         MaxRtrAdvInterval 10;
>         AdvLinkMTU 1500;
>         AdvDefaultPreference high;
>         prefix 2001:1291:2de:10::/64 {
>                 DeprecatePrefix on;
>                 AdvOnLink on;
>                 AdvAutonomous on;
>                 AdvRouterAddr on;
>         };
>         route ::/0 {
>                 RemoveRoute on;
>         };
>         RDNSS 2001:4860:4860::8844 2001:4860:4860::8888 { };
>         DNSSL igcorp.com.br { };
> };
> ---
> 
> 4- HIT TUE BUG!
> 
>  Go to `qemu-host-1.domain.com` and try to run "apt-get update", it will
> not work! Ping works... TCP connections doesn't.
> 
>  The gateway of `qemu-host-1.domain.com` (through ovsbr1p1), is the QEmu
> 2.0 Virtual Machine hosted on itself, the guest `guest-fw-1.domain.com`.
> 
> Details:
> 
> ---
> root@qemu-host-1:~# ip r
> default via 192.168.4.1 dev ovsbr1p1
> 192.168.4.0/24 dev ovsbr1p1  proto kernel  scope link  src 192.168.4.2
> 192.168.122.0/24 dev virbr0  proto kernel  scope link  src 192.168.122.1
> 
> root@qemu-host-1:~# ip -6 r | grep ovsbr1p1
> 2001:1291:200:850a::/64 dev ovsbr1p1  proto kernel  metric 256  expires 86397sec
> fe80::/64 dev ovsbr1p1  proto kernel  metric 256
> default via fe80::5054:ff:feb5:7744 dev ovsbr1p1  proto ra  metric 1024  expires 27sec
> 
> 
> # ping6 okay...
> root@qemu-host-1:~# ping6 google.com -c1
> PING google.com(2800:3f0:4001:815::1007) 56 data bytes
> 64 bytes from 2800:3f0:4001:815::1007: icmp_seq=1 ttl=55 time=44.5 ms
> 
> --- google.com ping statistics ---
> 1 packets transmitted, 1 received, 0% packet loss, time 0ms
> rtt min/avg/max/mdev = 44.579/44.579/44.579/0.000 ms
> 
> # traceroute6 okay...
> root@qemu-host-1:~# traceroute6 google.com
> traceroute to google.com (2800:3f0:4001:815::1007) from 2001:1291:200:850a:1054:3d86:369:d4b2, 30 hops max, 24 byte packets
>  1  2001:1291:200:850a::2 (2001:1291:200:850a::2)  0.394 ms  0.261 ms  0.223 ms
>  2  gw-1291.udi-01.br.sixxs.net (2001:1291:200:50a::1)  21.536 ms  20.738 ms  20.902 ms
>  3  brudi01.sixxs.net (2001:1291:2::b)  20.684 ms  20.74 ms  20.846 ms
>  4  ge-0-2-0-71.seed.ula001.ctbc.com.br (2001:1291:2::a)  197.392 ms  141.706 ms  21.058 ms
>  5  ge-5-2-0-0.core-d.ula001.ctbc.com.br (2001:1291:0:98::a)  21.069 ms  20.837 ms  20.903 ms
>  6  ae0-0.core-b.fac001.ctbc.com.br (2001:1291:0:d7::a)  24.564 ms  24.464 ms  24.649 ms
>  7  et-1-0-0-0.border-a.fac001.ctbc.com.br (2001:1291:0:4b::b)  24.734 ms  24.525 ms  25.273 ms
>  8  2001:1291:0:63::2 (2001:1291:0:63::2)  36.619 ms  36.245 ms  36.335 ms
>  9  2001:4860::1:0:4f20 (2001:4860::1:0:4f20)  36.285 ms  41.017 ms  36.375 ms
> 10  2001:4860:0:1::71 (2001:4860:0:1::71)  31.601 ms  31.623 ms  31.512 ms
> 11  2800:3f0:4001:815::12 (2800:3f0:4001:815::12)  30.826 ms  30.683 ms  30.769 ms
> 
> # NOTE: the second hope is the "guest-fw-1".
> 
> # "apt-get update", not okay! *BUG*
> 
> root@qemu-host-1:~# apt-get update
> 0% [Connecting to us.archive.ubuntu.com (2001:67c:1562::14)] [Connecting to sec
> 
> # it remains "Waiting for headers" forever...
> 
> # While waiting for "apt-get update" above, `tcpdump -ni ovsbr1p1`
> shows:
> 
> http://pastebin.com/2BUiNEfQ
> 
> ---
> 
> 
>  (OPTIONAL STEP - replace OpenvSwitch by bridge-utils - does not fix it!)
> 
>  Possible workarounds: is this an OpenvSwitch BUG? Lets try it with
> `bridge-utils` instead...
> 
>  * Reconfigure your "qemu-host-1.domain.com" to use `bridge-utils`,
> instead of openvswitch-switch.
> 
> 
> ------------------------
> 
> 1- Preparing the host, now using `bridge-utils` instead of OpenvSwitch:
> 
> - Reconfigure `qemu-host-1`s /etc/network/interfaces file with:
> 
> ---
> auto br0
> iface br0 inet manual
>         bridge_ports eth0
>         bridge_maxwait 5
>         bridge_fd 1
>         bridge_stp on
> 
> auto br1
> iface br1 inet manual
>         bridge_ports eth1
>         bridge_maxwait 5
>         bridge_fd 1
>         bridge_stp on
> 
> auto vlan100
> iface vlan100 inet6 auto
>         vlan_raw_device br1
> 
> iface vlan100 inet static
>         vlan_raw_device br1
>         address 192.168.1.10
>         netmask 24
>         gateway 192.168.1.1
> 
> auto br2
> iface br2 inet manual
>         bridge_ports eth2
>         bridge_maxwait 5
>         bridge_fd 1
>         bridge_stp on
> ---
> 
> 
> 2- New VM Configuration file (network-only section / cutted), adjusted
> to make use bridges from `bridge-utils` package:
> 
> ---
>     <interface type='bridge'>
>       <mac address='52:54:00:41:8c:3f'/>
>       <source bridge='br0'/>
>       <model type='virtio'/>
>       <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
>     </interface>
>     <interface type='bridge'>
>       <mac address='52:54:00:27:b2:7d'/>
>       <source bridge='br1'/>
>       <model type='virtio'/>
>       <address type='pci' domain='0x0000' bus='0x00' slot='0x09' function='0x0'/>
>     </interface>
>     <interface type='bridge'>
>       <mac address='52:54:00:ff:35:5c'/>
>       <source bridge='br2'/>
>       <model type='virtio'/>
>       <address type='pci' domain='0x0000' bus='0x00' slot='0x0a' function='0x0'/>
>     </interface>
> ---
> 
> * Start `guest-fw-1` as-is:
> 
>  virsh start guest-fw-1
> 
> 
> New try:
> 
> ---
> root@qemu-host-1:~# ip r
> default via 192.168.4.1 dev vlan100
> 192.168.4.0/24 dev vlan100 proto kernel  scope link  src 192.168.4.2
> 192.168.122.0/24 dev virbr0  proto kernel  scope link  src 192.168.122.1
> 
> root@qemu-host-1:~# ip -6 r | grep vlan100
> 2001:1291:200:850a::/64 dev vlan100  proto kernel  metric 256  expires 86397sec
> fe80::/64 dev vlan100  proto kernel  metric 256
> default via fe80::5054:ff:feb5:7744 dev vla100  proto ra  metric 1024  expires 27sec
> 
> root@qemu-host-1:~# ip -6 r | grep ovsbr1p1
> 2001:1291:200:850a::/64 dev ovsbr1p1  proto kernel  metric 256  expires 86394sec
> fe80::/64 dev ovsbr1p1  proto kernel  metric 256
> default via fe80::5054:ff:feb5:7744 dev ovsbr1p1  proto ra  metric 1024  expires 24sec
> 
> # ping6 okay...
> root@qemu-host-1:~# ping6 google.com -c1
> PING google.com(2800:3f0:4001:815::1007) 56 data bytes
> 64 bytes from 2800:3f0:4001:815::1007: icmp_seq=1 ttl=55 time=44.5 ms
> 
> --- google.com ping statistics ---
> 1 packets transmitted, 1 received, 0% packet loss, time 0ms
> rtt min/avg/max/mdev = 44.579/44.579/44.579/0.000 ms
> 
> # traceroute6 okay...
> root@qemu-host-1:~# traceroute6 google.com
> traceroute to google.com (2800:3f0:4001:815::1007) from 2001:1291:200:850a:1054:3d86:369:d4b2, 30 hops max, 24 byte packets
>  1  2001:1291:200:850a::2 (2001:1291:200:850a::2)  0.394 ms  0.261 ms  0.223 ms
>  2  gw-1291.udi-01.br.sixxs.net (2001:1291:200:50a::1)  21.536 ms  20.738 ms  20.902 ms
>  3  brudi01.sixxs.net (2001:1291:2::b)  20.684 ms  20.74 ms  20.846 ms
>  4  ge-0-2-0-71.seed.ula001.ctbc.com.br (2001:1291:2::a)  197.392 ms  141.706 ms  21.058 ms
>  5  ge-5-2-0-0.core-d.ula001.ctbc.com.br (2001:1291:0:98::a)  21.069 ms  20.837 ms  20.903 ms
>  6  ae0-0.core-b.fac001.ctbc.com.br (2001:1291:0:d7::a)  24.564 ms  24.464 ms  24.649 ms
>  7  et-1-0-0-0.border-a.fac001.ctbc.com.br (2001:1291:0:4b::b)  24.734 ms  24.525 ms  25.273 ms
>  8  2001:1291:0:63::2 (2001:1291:0:63::2)  36.619 ms  36.245 ms  36.335 ms
>  9  2001:4860::1:0:4f20 (2001:4860::1:0:4f20)  36.285 ms  41.017 ms  36.375 ms
> 10  2001:4860:0:1::71 (2001:4860:0:1::71)  31.601 ms  31.623 ms  31.512 ms
> 11  2800:3f0:4001:815::12 (2800:3f0:4001:815::12)  30.826 ms  30.683 ms  30.769 ms
> 
> 
> # BUG effect! "apt-get update", not okay!
> 
> root@qemu-host-1:~# apt-get update
> 0% [Connecting to us.archive.ubuntu.com (2001:67c:1562::14)] [Connecting to sec
> 
> # it remains "Waiting for headers" forever...
> 
> - So! It is not an OpenvSwitch BUG! Removing `bridge-utils` bridges,
> falling back to OpenvSwitch as we started.
> 
> 
> ** Workaround #2: Use Xen-4.4 instead of QEmu 2.0 / Back to OpenvSwitch.
> 
> 
> -- VM conf (`guest-fw-1` needs to have /etc/init/hvc0.conf):
> 
> ---
> name = "guest-fw-1"
> 
> uuid = "17e031c7-1264-4979-8f06-c5e016469474"
> 
> bootloader = "pygrub"
> 
> memory = 2048
> 
> vcpus = 2
> 
> vif = [ 'bridge=ovsbr0', 'bridge=ovsbr1', 'bridge=ovsbr2',
> 'bridge=ovsbr3', 'bridge=ovsbr4', 'bridge=ovsbr5' ]
> 
> disk = [ 'tap:raw:/var/lib/libvirt/images/guest-fw-1-disk0.img,xvda,rw' ]
> ---
> 
> Details - Working as expected when with Xen!! Look:
> 
> ---
> root@qemu-host-1:~# ping6 -c 1 google.com
> PING google.com(2800:3f0:4001:815::1002) 56 data bytes
> 64 bytes from 2800:3f0:4001:815::1002: icmp_seq=1 ttl=55 time=37.5 ms
> 
> 
> root@qemu-host-1:~# ip -6 r | grep ovsbr1p1
> 2001:1291:200:850a::/64 dev ovsbr1p1  proto kernel  metric 256  expires 86394sec
> fe80::/64 dev ovsbr1p1  proto kernel  metric 256 
> default via fe80::5054:ff:feb5:7744 dev ovsbr1p1  proto ra  metric 1024  expires 24sec
> 
> # *BUG dissapeared!*
> 
> root@qemu-host-1:~# apt-get update
> Ign http://us.archive.ubuntu.com trusty InRelease
> Ign http://security.ubuntu.com trusty-security InRelease
> Ign http://us.archive.ubuntu.com trusty-proposed InRelease
> Ign http://us.archive.ubuntu.com trusty-updates InRelease
> Ign http://us.archive.ubuntu.com trusty-backports InRelease
> Get:1 http://security.ubuntu.com trusty-security Release.gpg [933 B]
> Hit http://us.archive.ubuntu.com trusty Release.gpg
> Get:2 http://security.ubuntu.com trusty-security Release [59.7 kB]
> ........................
> Ign http://us.archive.ubuntu.com trusty/main Translation-en_US
> Ign http://us.archive.ubuntu.com trusty/multiverse Translation-en_US
> Ign http://us.archive.ubuntu.com trusty/restricted Translation-en_US
> Ign http://us.archive.ubuntu.com trusty/universe Translation-en_US
> Fetched 1,011 kB in 19s (50.7 kB/s)
> Reading package lists... Done
> ---
> 
> 
> Now, both Xen Dom0 (`qemu-host-1`) and DomU (`guest-fw-1`) works as expected! You guys can see that the `guest-fw-1` is working on top of Xen, as-is, I mean, the changes happened only at the Hypervisor itself, problem solved (not for QEmu)!
> 
> But, QEmu still have a problem, if I remove Xen, back to QEmu, then, the
> host `qemu-host-1` cannot browse the web again (`apt-get update` will
> not work if its gateway is a QEmu guest).
> 
> 
>  ** Workaround #3: Untagging the VLANs with OpenvSwitch and its "fake bridges".
> 
>  The presented workaround have one big downside, while it allows us to
> keep using QEmu (and KSM), it requires a complete reconfiguration of the
> `guest-fw-1` interfaces! Also, for each VLAN tag, you'll need to create
> a fake bridge, a new VirtIO NIC for your guest (this might add a bit of
> overhead for your hypervisor as a whole, I'm not sure), plus a lot of
> extra work... If you need to add a new VLAN to your `guest-fw-1`, you'll
> need to reboot it, to add a new VirtIO NIC (this isn't the best way to
> build hypervisors - not the best practice), this is just a real
> workaround that allows you to keep using QEmu (and benefits from KSM,
> Libvirt and etc)...
> 
>  While, when replacing QEmu by Xen, you don't need to change a single
> line within the guest itself...
> 
>  So, this network problem lies within the QEmu Virtual Machine!
> 
>  Doing this workaround:
> 
> 1- Untagging the VLANs at OpenvSwitch, because QEmu can't handle it:
> 
> ovs-vsctl add-br vlan10 ovsbr0 10
> ovs-vsctl add-br vlan100 ovsbr1 100
> ovs-vsctl add-br vlan200 ovsbr2 100
> 
> 2- Reconfigure the `guest-fw-1` to make use of new "fake bridges":
> 
> ---
>     <interface type='network'>
>       <mac address='52:54:00:41:8c:3f'/>
>       <source network='vlan10'/>
>       <model type='virtio'/>
>       <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
>     </interface>
>     <interface type='network'>
>       <mac address='52:54:00:27:b2:7d'/>
>       <source network='vlan100'/>
>       <model type='virtio'/>
>       <address type='pci' domain='0x0000' bus='0x00' slot='0x09' function='0x0'/>
>     </interface>
>     <interface type='network'>
>       <mac address='52:54:00:ff:35:5c'/>
>       <source network='vlan200'/>
>       <model type='virtio'/>
>       <address type='pci' domain='0x0000' bus='0x00' slot='0x0a' function='0x0'/>
>     </interface>
> ---
> 
> 3- Reconfigure `guest-gw-1`s /etc/network/interfaces file:
> 
> ---
> auto eth0
> iface eth0 inet static
> #        vlan_raw_device eth0
>         address 200.2.1.106
>         netmask 29
>         gateway 200.2.1.105
>         dns-nameserver 8.8.8.8
> 
> auto eth1
> iface eth1 inet6 static
> #        vlan_raw_device eth1
>         address 2001:129X:2XX:810X::2
>         netmask 64
>         dns-nameserver 2001:4860:4860::8844 2001:4860:4860::8888
> 
> iface eth1 inet static
> #        vlan_raw_device eth1
>         address 192.168.4.1
>         netmask 24
> 
> auto eth2
> iface eth2 inet6 static
> #        vlan_raw_device eth2
>         address 2001:1291:2de:10::1
>         netmask 64
> 
> iface eth2 inet static
> #        vlan_raw_device eth2
>         address 172.16.0.1
>         netmask 24
> ---
> 
> 4- Details: Working as expected when with QEmu but, without tagging the
> VLAN within the `guest-fw-1` itself.
> 
> ---
> root@qemu-host-1:~# ping6 -c 1 google.com
> PING google.com(2800:3f0:4001:815::1002) 56 data bytes
> 64 bytes from 2800:3f0:4001:815::1002: icmp_seq=1 ttl=55 time=37.5 ms
> 
> 
> root@qemu-host-1:~# ip -6 r | grep ovsbr1p1
> 2001:1291:200:850a::/64 dev ovsbr1p1  proto kernel  metric 256  expires 86394sec
> fe80::/64 dev ovsbr1p1  proto kernel  metric 256.
> default via fe80::5054:ff:feb5:7744 dev ovsbr1p1  proto ra  metric 1024  expires 24sec
> 
> # *BUG dissapeared!*
> 
> root@qemu-host-1:~# apt-get update
> Ign http://us.archive.ubuntu.com trusty InRelease
> Ign http://security.ubuntu.com trusty-security InRelease
> Ign http://us.archive.ubuntu.com trusty-proposed InRelease
> Ign http://us.archive.ubuntu.com trusty-updates InRelease
> Ign http://us.archive.ubuntu.com trusty-backports InRelease
> Get:1 http://security.ubuntu.com trusty-security Release.gpg [933 B]
> Hit http://us.archive.ubuntu.com trusty Release.gpg
> Get:2 http://security.ubuntu.com trusty-security Release [59.7 kB]
> ........................
> Ign http://us.archive.ubuntu.com trusty/main Translation-en_US
> Ign http://us.archive.ubuntu.com trusty/multiverse Translation-en_US
> Ign http://us.archive.ubuntu.com trusty/restricted Translation-en_US
> Ign http://us.archive.ubuntu.com trusty/universe Translation-en_US
> Fetched 1,011 kB in 19s (50.7 kB/s)
> Reading package lists... Done
> ---
> 
> Conclusion:
> 
> A QEmu guest router does not route tagged VLAN packages that are
> originated at its host, neighter from others guests hosted at the same
> hypervisor. Making it impossible to create a virtual network within a
> hypervisor.
> 
> Best Regards,
> Thiago Martins
> 
> ** Affects: qemu
>      Importance: Undecided
>          Status: New
>