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Libvirt provides a portable, long term stable C API for managing the virtualization technologies provided by many operating systems. It includes support for QEMU, KVM, Xen, LXC, bhyve, Virtuozzo, VMware vCenter and ESX, VMware Desktop, Hyper-V, VirtualBox and the POWER Hypervisor.

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Laine Stump a60ee91400 util: allow tap-based guest interfaces to have MAC address prefix 0xFE Back in July 2010, commit `6ea90b84` (meant to resolve https://bugzilla.redhat.com/571991 ) added code to set the MAC address of any tap device to the associated guest interface's MAC, but with the first byte replaced with 0xFE. This was done in order to assure that 1) the tap MAC and guest interface MAC were different (otherwise L2 forwarding through the tap would not work, and the kernel would repeatedly issue a warning stating as much). 2) any bridge device that had one of these taps attached would not take on the MAC of the tap (leading to network instability as guests started and stopped) A couple years later, https://bugzilla.redhat.com/798467 was filed, complaining that a user could configure a tap-based guest interface to have a MAC address that itself had a first byte of 0xFE, silently (other than the kernel warning messages) resulting in a non-working configuration. This was fixed by commit `5d571045`, which logged an error and failed the guest start / interface attach if the MAC's first byte was 0xFE. Although this restriction only reduces the potential pool of MAC addresses from 2^46 (last two bits of byte 1 must be set to 10) by 2^32 (still 4 orders of magnitude larger than the entire IPv4 address space), it also means that management software that autogenerates MAC addresses must have special code to avoid an 0xFE prefix. Now after 7 years, someone has noticed this restriction and requested that we remove it. So instead of failing when 0xFE is found as the first byte, this patch removes the restriction by just replacing the first byte in the tap device MAC with 0xFA if the first byte in the guest interface is 0xFE. 0xFA is the next-highest value that still has 10 as the lowest two bits, and still 2) meets the requirement of "tap MAC must be different from guest interface MAC", and 3) is high enough that there should never be an issue of the attached bridge device taking on the MAC of the tap. The result is that any MAC can be chosen by management software (although it would still not work correctly if a multicast MAC (lowest bit of first byte set to 1) was chosen), but that's a different issue). Signed-off-by: Laine Stump <laine@redhat.com> Reviewed-by: Michal Privoznik <mprivozn@redhat.com		2019-08-12 14:22:05 -04:00
.ctags.d	maint: Add support for .ctags.d	2019-05-31 17:54:28 +02:00
.gnulib@c8e2eee548	maint: Update to latest gnulib	2019-08-08 07:31:03 -05:00
build-aux	build: use @CONFIG@ instead of ::CONFIG:: in augeas tests	2019-08-09 14:06:31 +01:00
docs	qemu: support for kvm-hint-dedicated performance hint	2019-08-12 15:13:04 +02:00
examples	examples: Group all C programs together	2019-06-03 17:27:43 +02:00
gnulib	maint: Fix VPATH build	2019-01-07 21:56:16 -06:00
include/libvirt	backup: Introduce virDomainCheckpoint APIs	2019-07-26 16:48:58 -05:00
m4	m4: Drop libxml2 version number from configure help	2019-08-12 09:31:22 +02:00
po	po: refresh translations from zanata	2019-07-30 12:43:31 +01:00
src	util: allow tap-based guest interfaces to have MAC address prefix 0xFE	2019-08-12 14:22:05 -04:00
tests	tests: Update replies for QEMU 2.12.0 on aarch64	2019-08-12 16:49:31 +02:00
tools	build: don't hardcode /etc in the config related files	2019-08-09 14:06:31 +01:00
.color_coded.in	Add color_coded support	2017-05-09 09:51:11 +02:00
.ctags	ctags: Generate tags for headers, i.e. function prototypes	2018-09-18 14:21:33 +02:00
.dir-locals.el	build: avoid tabs that failed syntax-check	2012-09-06 09:43:46 -06:00
.gitignore	vz: introduce virtvzd daemon	2019-08-09 14:06:31 +01:00
.gitlab-ci.yml	gitlab: Perform some builds on Debian 10	2019-07-11 15:03:39 +02:00
.gitmodules	gnulib: switch to use https:// instead of git:// protocol	2018-03-19 16:32:34 +00:00
.gitpublish	git: add config file telling git-publish how to send patches	2018-04-23 11:36:09 +01:00
.mailmap	mailmap: Remove some duplicates	2019-06-07 13:18:08 +02:00
.travis.yml	travis: put macOS script inline in the macOS matrix entry	2019-04-11 18:38:56 +01:00
.ycm_extra_conf.py.in	Add YouCompleteMe support	2017-05-09 09:51:11 +02:00
ABOUT-NLS	po: provide custom make rules for po file management	2018-04-19 10:35:58 +01:00
AUTHORS.in	AUTHORS: Add Katerina Koukiou	2018-07-17 17:01:19 +02:00
autogen.sh	po: provide custom make rules for po file management	2018-04-19 10:35:58 +01:00
bootstrap	maint: update gnulib for syntax-check on BSD	2019-01-07 13:54:07 -06:00
bootstrap.conf	maint: Stop generating ChangeLog from git	2019-04-03 09:45:25 +02:00
cfg.mk	tools: avoid accidentally using files from gnulib	2019-08-08 13:32:02 +01:00
ChangeLog	maint: Stop generating ChangeLog from git	2019-04-03 09:45:25 +02:00
config-post.h	nss: only link to yajl library and nothing else	2019-08-07 16:54:02 +01:00
configure.ac	build: drop libvirt setuid library build	2019-08-07 16:54:01 +01:00
COPYING	maint: follow recommended practice for using LGPL	2013-05-20 14:15:21 -06:00
COPYING.LESSER	maint: Remove control characters from LGPL license file	2015-09-25 09:16:24 +02:00
gitdm.config	gitdm: Add gitdm configuration	2019-06-07 13:18:14 +02:00
libvirt-admin.pc.in	Add libvirt-admin library	2015-06-16 13:46:20 +02:00
libvirt-lxc.pc.in	Add pkg-config files for libvirt-qemu & libvirt-lxc	2014-06-23 16:17:27 +01:00
libvirt-qemu.pc.in	Add pkg-config files for libvirt-qemu & libvirt-lxc	2014-06-23 16:17:27 +01:00
libvirt.pc.in	Add pkg-config files for libvirt-qemu & libvirt-lxc	2014-06-23 16:17:27 +01:00
libvirt.spec.in	remote: enable connecting to the per-driver daemons	2019-08-09 14:06:31 +01:00
Makefile.am	Don't include Makefile.ci in Makefile.am	2019-05-10 09:12:52 +02:00
Makefile.ci	ci: Update image list	2019-07-11 15:03:37 +02:00
Makefile.nonreentrant	Remove backslash alignment attempts	2017-11-03 13:24:12 +01:00
mingw-libvirt.spec.in	backup: Introduce virDomainCheckpoint APIs	2019-07-26 16:48:58 -05:00
README	Provide a useful README file	2017-05-22 17:01:37 +01:00
README-hacking	docs: update all GIT repo examples to use https:// protocol	2018-03-21 14:48:01 +00:00
README.md	README: fix license typo	2019-07-25 09:21:28 -06:00
run.in	run: Don't export unnecessary paths	2019-03-15 11:50:23 +01:00

README.md

Libvirt API for virtualization

For some of these hypervisors, it provides a stateful management daemon which runs on the virtualization host allowing access to the API both by non-privileged local users and remote users.

Layered packages provide bindings of the libvirt C API into other languages including Python, Perl, PHP, Go, Java, OCaml, as well as mappings into object systems such as GObject, CIM and SNMP.

Further information about the libvirt project can be found on the website:

https://libvirt.org

License

The libvirt C API is distributed under the terms of GNU Lesser General Public License, version 2.1 (or later). Some parts of the code that are not part of the C library may have the more restrictive GNU General Public License, version 2.0 (or later). See the files COPYING.LESSER and COPYING for full license terms & conditions.

Installation

Libvirt uses the GNU Autotools build system, so in general can be built and installed with the usual commands. For example, to build in a manner that is suitable for installing as root, use:

$ ./configure --prefix=/usr --sysconfdir=/etc --localstatedir=/var
$ make
$ sudo make install

While to build & install as an unprivileged user

$ ./configure --prefix=$HOME/usr
$ make
$ make install

The libvirt code relies on a large number of 3rd party libraries. These will be detected during execution of the configure script and a summary printed which lists any missing (optional) dependencies.

Contributing

The libvirt project welcomes contributions in many ways. For most components the best way to contribute is to send patches to the primary development mailing list. Further guidance on this can be found on the website:

https://libvirt.org/contribute.html

Contact

The libvirt project has two primary mailing lists:

libvirt-users@redhat.com (for user discussions)
libvir-list@redhat.com (for development only)

Further details on contacting the project are available on the website:

https://libvirt.org/contact.html