This fixes https://bugzilla.redhat.com/show_bug.cgi?id=609463
The problem was that, since a bridge always acquires the MAC address
of the connected interface with the numerically lowest MAC, as guests
are started and stopped, it was possible for the MAC address to change
over time, and this change in the network was being detected by
Windows 7 (it sees the MAC of the default route change), so on each
reboot it would bring up a dialog box asking about this "new network".
The solution is to create a dummy tap interface with a MAC guaranteed
to be lower than any guest interface's MAC, and attach that tap to the
bridge as soon as it's created. Since all guest MAC addresses start
with 0xFE, we can just generate a MAC with the standard "0x52, 0x54,
0" prefix, and it's guaranteed to always win (physical interfaces are
never connected to these bridges, so we don't need to worry about
competing numerically with them).
Note that the dummy tap is never set to IFF_UP state - that's not
necessary in order for the bridge to take its MAC, and not setting it
to UP eliminates the clutter of having an (eg) "virbr0-nic" displayed
in the output of the ifconfig command.
I chose to not auto-generate the MAC address in the network XML
parser, as there are likely to be consumers of that API that don't
need or want to have a MAC address associated with the
bridge.
Instead, in bridge_driver.c when the network is being defined, if
there is no MAC, one is generated. To account for virtual network
configs that already exist when upgrading from an older version of
libvirt, I've added a %post script to the specfile that searches for
all network definitions in both the config directory
(/etc/libvirt/qemu/networks) and the state directory
(/var/lib/libvirt/network) that are missing a mac address, generates a
random address, and adds it to the config (and a matching address to
the state file, if there is one).
docs/formatnetwork.html.in: document <mac address.../>
docs/schemas/network.rng: add nac address to schema
libvirt.spec.in: %post script to update existing networks
src/conf/network_conf.[ch]: parse and format <mac address.../>
src/libvirt_private.syms: export a couple private symbols we need
src/network/bridge_driver.c:
auto-generate mac address when needed,
create dummy interface if mac address is present.
tests/networkxml2xmlin/isolated-network.xml
tests/networkxml2xmlin/routed-network.xml
tests/networkxml2xmlout/isolated-network.xml
tests/networkxml2xmlout/routed-network.xml: add mac address to some tests
At this point everything is already in place to make IPv6 happen, we just
need to add a few rules, remove some checks for IPv4-only, and document
the changes to the XML on the website.
This patch is the result of running the following command in the docs
directory: sed -i 's/\t/ /g; s/\s*$//' *.html.in
* docs/*.html.in:convert tabs into 8 spaces and remove trailing whitespace
This patch adds an optional attribute to the <bootp> tag, that
allows to specify a TFTP server address other than the address of
the DHCP server itself.
This can be used to forward the BOOTP settings of the host down to the
guest. This is something that configurations such as Xen's default
network achieve naturally, but must be done manually for NAT.
* docs/formatnetwork.html.in: Document new attribute.
* docs/schemas/network.rng: Add it to schema.
* src/conf/network_conf.h: Add it to struct.
* src/conf/network_conf.c: Add it to parser and pretty printer.
* src/network/bridge_driver.c: Put it in the dnsmasq command line.
* tests/networkxml2xmlin/netboot-proxy-network.xml
tests/networkxml2xmlout/netboot-proxy-network.xml
tests/networkxml2xmltest.c: add new tests
Currently, libvirtd will start a dnsmasq process for the virtual
network, but (aside from killing the dnsmasq process and replacing it),
there's no way to define tftp boot options.
This change introduces the appropriate tags to the dhcp configuration:
<network>
<name>default</name>
<bridge name="virbr%d" />
<forward/>
<ip address="192.168.122.1" netmask="255.255.255.0">
<tftp root="/var/lib/tftproot" />
<dhcp>
<range start="192.168.122.2" end="192.168.122.254" />
<bootp file="pxeboot.img"/>
</dhcp>
</ip>
</network>
When the attributes are present, these are passed to the
arguments to dnsmasq:
dnsmasq [...] --enable-tftp --tftp-root /srv/tftp --dhcp-boot pxeboot.img
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^
from <tftp /> from <bootp />
At present, only local tftp servers are supported (ie, dnsmasq runs as
the tftp server), but we could improve this in future by adding a
server= attribute.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2009-09-21 Paolo Bonzini <pbonzini@redhat.com>
Jeremy Kerr <jk@ozlabs.org>
* docs/formatnetwork.html.in: Document new tags.
* docs/formatnetwork.html: Regenerate.
* docs/schemas/network.rng: Update.
* src/network_conf.c (virNetworkDefFree): Free new fields.
(virNetworkDHCPRangeDefParseXML): Parse <bootp>.
(virNetworkIPParseXML): New, parsing <dhcp> and <tftp>.
(virNetworkDefParseXML): Use virNetworkIPParseXML instead of
virNetworkDHCPRangeDefParseXML.
(virNetworkDefFormat): Pretty print new fields.
* src/network_conf.h (struct _virNetworkDef): Add netboot fields.
* src/network_driver.c (networkBuildDnsmasqArgv): Add
TFTP and BOOTP arguments.
* tests/Makefile.am (EXTRA_DIST): Add networkschemadata.
* tests/networkschematest: Look in networkschemadata.
* tests/networkschemadata/netboot-network.xml: New.
