This patch is in response to:
https://bugzilla.redhat.com/show_bug.cgi?id=798467
If a guest's tap device is created using the same MAC address the
guest uses for its own network card (which connects to the tap
device), the Linux kernel will log the following message and traffic
will not pass:
kernel: vnet9: received packet with own address as source address
This patch disallows MAC addresses with a first byte of 0xFE, but only in
the case that the MAC address is used for a guest interface that's
connected by way of a standard tap device. (In other words, the
validation is done at runtime at the same place the MAC address is
modified for the tap device, rather than when mac address is parsed,
the idea being that it is then we know for sure the address will be
problematic.)
This patch will allow OpenFlow controllers to identify which interface
belongs to a particular VM by using the Domain UUID.
ovs-vsctl get Interface vnet0 external_ids
{attached-mac="52:54:00:8C:55:2C", iface-id="83ce45d6-3639-096e-ab3c-21f66a05f7fa", iface-status=active, vm-id="142a90a7-0acc-ab92-511c-586f12da8851"}
V2 changes:
Replaced vm-uuid with vm-id. There was a discussion in Open vSwitch
mailinglist that we should stick with the same DB key postfixes for the
sake of consistency (e.g iface-id, vm-id ...).
With an additional new bool added to determine whether or not to
discourage the use of the supplied MAC address by the bridge itself,
virNetDevTapCreateInBridgePort had three booleans (well, 2 bools and
an int used as a bool) in the arg list, which made it increasingly
difficult to follow what was going on. This patch combines those three
into a single flags arg, which not only shortens the arg list, but
makes it more self-documenting.
When a tap device for a domain is created and attached to a bridge,
the first byte of the tap device MAC address is set to 0xFE, while the
rest is set to match the MAC address that will be presented to the
guest as its network device MAC address. Setting this high value in
the tap's MAC address discourages the bridge from using the tap
device's MAC address as the bridge's own MAC address (Linux bridges
always take on the lowest numbered MAC address of all attached devices
as their own).
In one case within libvirt, a tap device is created and attached to
the bridge with the intent that its MAC address be taken on by the
bridge as its own (this is used to assure that the bridge has a fixed
MAC address to prevent network outages created by the bridge MAC
address "flapping" as guests are started and stopped). In this case,
the first byte of the mac address is *not* altered to 0xFE.
In the current code, callers to virNetDevTapCreateInBridgePort each
make the MAC address modification themselves before calling, which
leads to code duplication, and also prevents lower level functions
from knowing the real MAC address being used by the guest. The problem
here is that openvswitch bridges must be informed about this MAC
address, or they will be unable to pass traffic to/from the guest.
This patch centralizes the location of the MAC address "0xFE fixup"
into virNetDevTapCreateInBridgePort(), meaning 1) callers of this
function no longer need the extra strange bit of code, and 2)
bitNetDevTapCreateBridgeInPort itself now is called with the guest's
unaltered MAC address, and can pass it on, unmodified, to
virNetDevOpenvswitchAddPort.
There is no other behavioral change created by this patch.
This patch allows libvirt to add interfaces to already
existing Open vSwitch bridges. The following syntax in
domain XML file can be used:
<interface type='bridge'>
<mac address='52:54:00:d0:3f:f2'/>
<source bridge='ovsbr'/>
<virtualport type='openvswitch'>
<parameters interfaceid='921a80cd-e6de-5a2e-db9c-ab27f15a6e1d'/>
</virtualport>
<address type='pci' domain='0x0000' bus='0x00'
slot='0x03' function='0x0'/>
</interface>
or if libvirt should auto-generate the interfaceid use
following syntax:
<interface type='bridge'>
<mac address='52:54:00:d0:3f:f2'/>
<source bridge='ovsbr'/>
<virtualport type='openvswitch'>
</virtualport>
<address type='pci' domain='0x0000' bus='0x00'
slot='0x03' function='0x0'/>
</interface>
It is also possible to pass an optional profileid. To do that
use following syntax:
<interface type='bridge'>
<source bridge='ovsbr'/>
<mac address='00:55:1a:65:a2:8d'/>
<virtualport type='openvswitch'>
<parameters interfaceid='921a80cd-e6de-5a2e-db9c-ab27f15a6e1d'
profileid='test-profile'/>
</virtualport>
</interface>
To create Open vSwitch bridge install Open vSwitch and
run the following command:
ovs-vsctl add-br ovsbr
The src/util/network.c file is a dumping ground for many different
APIs. Split it up into 5 pieces, along functional lines
- src/util/virnetdevbandwidth.c: virNetDevBandwidth type & helper APIs
- src/util/virnetdevvportprofile.c: virNetDevVPortProfile type & helper APIs
- src/util/virsocketaddr.c: virSocketAddr and APIs
- src/conf/netdev_bandwidth_conf.c: XML parsing / formatting
for virNetDevBandwidth
- src/conf/netdev_vport_profile_conf.c: XML parsing / formatting
for virNetDevVPortProfile
* src/util/network.c, src/util/network.h: Split into 5 pieces
* src/conf/netdev_bandwidth_conf.c, src/conf/netdev_bandwidth_conf.h,
src/conf/netdev_vport_profile_conf.c, src/conf/netdev_vport_profile_conf.h,
src/util/virnetdevbandwidth.c, src/util/virnetdevbandwidth.h,
src/util/virnetdevvportprofile.c, src/util/virnetdevvportprofile.h,
src/util/virsocketaddr.c, src/util/virsocketaddr.h: New pieces
* daemon/libvirtd.h, daemon/remote.c, src/conf/domain_conf.c,
src/conf/domain_conf.h, src/conf/network_conf.c,
src/conf/network_conf.h, src/conf/nwfilter_conf.h,
src/esx/esx_util.h, src/network/bridge_driver.c,
src/qemu/qemu_conf.c, src/rpc/virnetsocket.c,
src/rpc/virnetsocket.h, src/util/dnsmasq.h, src/util/interface.h,
src/util/iptables.h, src/util/macvtap.c, src/util/macvtap.h,
src/util/virnetdev.h, src/util/virnetdevtap.c,
tools/virsh.c: Update include files
Following the renaming of the bridge management APIs, we can now
split the source file into 3 corresponding pieces
* src/util/virnetdev.c: APIs for any type of network interface
* src/util/virnetdevbridge.c: APIs for bridge interfaces
* src/util/virnetdevtap.c: APIs for TAP interfaces
* src/util/virnetdev.c, src/util/virnetdev.h,
src/util/virnetdevbridge.c, src/util/virnetdevbridge.h,
src/util/virnetdevtap.c, src/util/virnetdevtap.h: Copied
from bridge.{c,h}
* src/util/bridge.c, src/util/bridge.h: Split into 3 pieces
* src/lxc/lxc_driver.c, src/network/bridge_driver.c,
src/openvz/openvz_driver.c, src/qemu/qemu_command.c,
src/qemu/qemu_conf.h, src/uml/uml_conf.c, src/uml/uml_conf.h,
src/uml/uml_driver.c: Update #include directives
