When this flag is set for an interface attached to a bridge, traffic
to/from the specified interface can only enter/exit the bridge via
another attached interface that *doesn't* have the BR_ISOLATED flag
set. This can be used to permit guests to communicate with the rest of
the network, but not with each other.
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
When libvirt first implemented a stable and configurable MAC address
for the bridges created for libvirt virtual networks (commit
5754dbd56d, in libvirt v0.8.8) most distro stable releases didn't
support explicitly setting the MAC address of a bridge; the bridge
just always assumed the lowest numbered MAC of all attached
interfaces. Because of this, we stabilized the bridge MAC address by
creating a "dummy" tap interface with a MAC address guaranteed to be
lower than any of the guest tap devices' MACs (which all started with
0xFE, so it's not difficult to do) and attached it to the bridge -
this was the inception of the "virbr0-nic" device that has confused so
many people over the years.
Even though the linux kernel had recently gained support for
explicitly setting a bridge MAC, we deemed it unnecessary to set the
MAC that way, because the other (indirect) method worked everywhere.
But recently there have been reports that the bridge MAC address was
not following the setting in the network config, and mismatched the
MAC of the dummy tap device (which was still correct). It turns out
that this is due to a change in systemd-242 that persists whatever MAC
address is set for a bridge when it's initially started. According to
the systemd NEWS file entry for version 242
(https://github.com/systemd/systemd/blob/master/NEWS):
"if a bridge interface is created without any slaves, and gains
a slave later, then now the bridge does not inherit slave's MAC."
This change was the result of:
https://github.com/systemd/systemd/issues/3374
(apparently if there is no MAC saved for a bridge by the name of a
bridge being created, the random MAC generated during creation is
saved, and then that same MAC is used to explicitly set the MAC each
time it is created). Once a bridge has an explicitly set MAC, the "use
the lowest numbered MAC of attached devices" rule is ignored, so our
dummy tap device is like the goggles - it does nothing! (well, almost).
We could whine about changes in default behavior, etc. etc., but
because the change was in response to actual user problems, that seems
likely a fruitless task. Fortunately, time has marched on, and even
distro releases that are old enough that they are no longer supported
by upstream libvirt (e.g. RHEL6) have support for explicitly setting a
bridge device MAC address, either during creation or with a separate
ioctl after creation, so we can now do that.
To enable explicitly setting the mac during bridge creation, we add a
mac arg to virNetDevBridgeCreate(). In the case of platforms where
the bridge is created with a netlink RTM_NEWLINK message, we just add
that mac to the message. For platforms that still use an ioctl (either
SIOCBRADDBR or SIOCIFCREATE2), we make a separate call to
virNetDevSetMAC() after creating the bridge.
(NB: I was unable to test the calling of virNetDevSetMAC() from the
SIOCIFCREATE2 (BSD) version of virNetDevBridgeCreate(); even though I
managed to get a FreeBSD system setup and libvirt built there, when I
tried to start the default network the SIOCIFCREATE2 ioctl itself
failed, so it never even got to the virNetDevSetMAC(). That leaves the
FreeBSD implementation untested.)
This makes the dummy tap pointless for purposes of setting the MAC
address, but it is still useful for IPv6 DAD initialization (which
apparently requires at least one interface to be attached to the
bridge and online), as well as for setting an initial MTU for the
bridge, so it hasn't been removed.
(NB: we can safely *always* call virNetDevBridgeCreate() with
&def->mac from the network driver because, in spite of the existence
of a "mac_specified" bool in the config suggesting that it may not
always be present, in reality a mac address will always be added to
any network that doesn't have one - this is guaranteed in all cases by
commit a47ae7c004)
https://bugzilla.redhat.com/show_bug.cgi?id=1760851
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
Require that all headers are guarded by a symbol named
LIBVIRT_$FILENAME
where $FILENAME is the uppercased filename, with all characters
outside a-z changed into '_'.
Note we do not use a leading __ because that is technically a
namespace reserved for the toolchain.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
In many files there are header comments that contain an Author:
statement, supposedly reflecting who originally wrote the code.
In a large collaborative project like libvirt, any non-trivial
file will have been modified by a large number of different
contributors. IOW, the Author: comments are quickly out of date,
omitting people who have made significant contribitions.
In some places Author: lines have been added despite the person
merely being responsible for creating the file by moving existing
code out of another file. IOW, the Author: lines give an incorrect
record of authorship.
With this all in mind, the comments are useless as a means to identify
who to talk to about code in a particular file. Contributors will always
be better off using 'git log' and 'git blame' if they need to find the
author of a particular bit of code.
This commit thus deletes all Author: comments from the source and adds
a rule to prevent them reappearing.
The Copyright headers are similarly misleading and inaccurate, however,
we cannot delete these as they have legal meaning, despite being largely
inaccurate. In addition only the copyright holder is permitted to change
their respective copyright statement.
Reviewed-by: Erik Skultety <eskultet@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
These two functions use netlink RTM_NEWNEIGH and RTM_DELNEIGH messages
to add and delete entries from a bridge's fdb. The bridge itself is
not referenced in the arguments to the functions, only the name of the
device that is attached to the bridge (since a device can only be
attached to one bridge at a time, and must be attached for this
function to make sense, the kernel easily infers which bridge's fdb is
being modified by looking at the device name/index).
https://www.gnu.org/licenses/gpl-howto.html recommends that
the 'If not, see <url>.' phrase be a separate sentence.
* tests/securityselinuxhelper.c: Remove doubled line.
* tests/securityselinuxtest.c: Likewise.
* globally: s/; If/. If/
Per the FSF address could be changed from time to time, and GNU
recommends the following now: (http://www.gnu.org/licenses/gpl-howto.html)
You should have received a copy of the GNU General Public License
along with Foobar. If not, see <http://www.gnu.org/licenses/>.
This patch removes the explicit FSF address, and uses above instead
(of course, with inserting 'Lesser' before 'General').
Except a bunch of files for security driver, all others are changed
automatically, the copyright for securify files are not complete,
that's why to do it manually:
src/security/security_selinux.h
src/security/security_driver.h
src/security/security_selinux.c
src/security/security_apparmor.h
src/security/security_apparmor.c
src/security/security_driver.c
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
