Commit Graph

580 Commits

Author SHA1 Message Date
Daniel P. Berrangé
c6cbe18771 network: delay global firewall setup if no networks are running
Creating firewall rules for the virtual networks causes the kernel to
load the conntrack module. This imposes a significant performance
penalty on Linux network traffic. Thus we want to only take that hit if
we actually have virtual networks running.

We need to create global firewall rules during startup in order to
"upgrade" rules for any running networks created by older libvirt.
If no running networks are present though, we can safely delay setup
until the time we actually start a network.

Reviewed-by: Jim Fehlig <jfehlig@suse.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-05-23 16:29:48 +01:00
Daniel P. Berrangé
3b66bd9aa1 network: add more debugging of firewall chain creation
Reviewed-by: Jim Fehlig <jfehlig@suse.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-05-23 16:28:15 +01:00
Daniel P. Berrangé
4330d13852 network: pull global chain init into separate method
Pull the logic for creating global iptables chains into a separate
method and protect its invocation with virOnce, to make it possible
to reuse it in non-startup paths.

Reviewed-by: Jim Fehlig <jfehlig@suse.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-05-23 16:28:12 +01:00
Michal Privoznik
43808f3e90 networkStartNetworkVirtual: Dissolve 'err0' label in 'error'
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
2019-05-21 13:53:31 +02:00
Michal Privoznik
711f8e0866 networkStartNetworkVirtual: Dissolve 'err1' label in 'error'
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
2019-05-21 13:52:19 +02:00
Michal Privoznik
90ab480cab networkStartNetworkVirtual: Dissolve 'err2' label in 'error'
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
2019-05-21 13:48:58 +02:00
Michal Privoznik
dafe15d524 networkStartNetworkVirtual: Dissolve 'err3' label in 'error'
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
2019-05-21 13:48:13 +02:00
Michal Privoznik
12288fae6b networkStartNetworkVirtual: Dissolve 'err4' label in 'error'
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
2019-05-21 13:47:10 +02:00
Michal Privoznik
9e3356ea1e networkStartNetworkVirtual: s/err5/error
In attempt to getting rid of errN labels let's start with the
most upper one and rename it to 'error'.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>
2019-05-21 13:36:18 +02:00
Daniel P. Berrangé
e5df4edefa src: don't statically link code that's already in libvirt.so
Various binaries are statically linking to libvirt_util.la and
other intermediate libraries we build. These intermediate libs
all get built into the main libvirt.so shared library eventually,
so we can dynamically link to that instead and reduce the on disk
footprint.

In libvirt-daemon RPM:

            virtlockd: 1.6 MB -> 153 KB
             virtlogd: 1.6 MB -> 157 KB
     libvirt_iohelper: 937 KB -> 23 KB

In libvirt-daemon-driver-network RPM:

 libvirt_leaseshelper: 940 KB -> 26 KB

In libvirt-daemon-driver-storage-core RPM:

   libvirt_parthelper: 926 KB -> 21 KB

IOW, about 5.6 MB total space saving in a build done on Fedora 30
x86_64 architecture.

Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-05-17 14:34:45 +01:00
Daniel P. Berrangé
04e4307d34 Revert "network: use 'bridge' as actual type instead of 'network'"
This caused the live XML to report the 'bridge' type instead of the
'network' type, which is a behavioural regression.

It also breaks 'virsh domif-setlink', 'virsh update-device' and
'virsh domiftune'

This reverts commit 518026e159.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-04-30 14:42:34 +01:00
Michal Privoznik
1cc1b8360b networkStartNetworkVirtual: Don't overwrite error in 'err5'
If there's an error when setting up QoS on a bridge the control
jumps over to 'err5' label. Here, the virNetDevBandwidthClear()
is called to clear out any partially set QoS. This function can
also report an error which would overwrite the actual error that
caused us jumping here. Use virErrorPreserveLast() to preserve
the original error.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
2019-04-24 09:33:45 +02:00
Syed Humaid
e9d4912cc0 network: Convert to virErrorRestore/virErrorPreserveLast
Replaced usage of virSaveLastError and virSetError/virFreeError with
virErrorPreserveLast and virErrorRestore respectively.

Signed-off-by: Syed Humaid <syedhumaidbinharoon@gmail.com>
2019-04-23 15:40:59 +02:00
Daniel P. Berrangé
b806a60eaf network: move re-attach of bridge device out of network driver
During initial NIC setup the hypervisor drivers are responsible for
attaching the TAP device to the bridge device. Any fixup after libvirtd
restarts should thus also be their responsibility.

Reviewed-by: Laine Stump <laine@laine.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-04-18 13:10:26 +01:00
Daniel P. Berrangé
518026e159 network: use 'bridge' as actual type instead of 'network'
Ports allocated on virtual networks with type=nat|route|open all get
given an actual type of 'network'.

Only ports in networks with type=bridge use an actual type of 'bridge'.

This distinction makes little sense since the virtualization drivers
will treat both actual types in exactly the same way, as they're all
just bridge devices a VM needs to be connected to.

This doesn't affect user visible XML since the "actual" device XML
is internal only, but we need code to convert the data upgrades.

Reviewed-by: Laine Stump <laine@laine.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-04-18 13:10:00 +01:00
Daniel P. Berrangé
9900da3c93 network: explain reason for bandwidth floor rejection
Reword error messages to make it clear that the combined floor settings
of all NICs are exceeding the network inbound peak/average
settings. Including the actual values being checked helps to diagnose
what is actually wrong.

Reviewed-by: Laine Stump <laine@laine.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-04-18 11:18:43 +01:00
Daniel P. Berrangé
557a96e0f4 network: ensure floor sum is reset to zero when starting networks
In extreme cases libvirt can get mixed up about what VMs are running and
attached to a network leading to the cached floor sum value being
outdated. When this happens the only option is to destroy the network
and then restart libvirtd. If we set floor sum back to zero when
starting the network, we avoid the need for a libvirtd restart at least.

Reviewed-by: Laine Stump <laine@laine.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-04-18 11:18:31 +01:00
Daniel P. Berrangé
d0a160d645 network: stop passing virDomainNetDefPtr into bandwidth functions
The networkPlugBandwidth & networkUnplugBandwidth methods currently take
a virDomainNetDefPtr. To remove the dependency on the domain config
struct, pass individual parameters instead.

Reviewed-by: Laine Stump <laine@laine.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-04-17 14:12:56 +01:00
Daniel P. Berrangé
85f915d8be network: unconditionally merge port profiles
All but one of the network types supports port profiles. Rather than
duplicating the code to merge profiles 3 times, do it once and then
later report an error if used from the wrong place.

Reviewed-by: Laine Stump <laine@laine.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-04-17 14:12:56 +01:00
Daniel P. Berrangé
3e213d43b1 network: use virNetDevTapReattachBridge API
Switch over to use the new API for re-attaching the bridge device

Reviewed-by: Cole Robinson <crobinso@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-04-16 14:44:53 +01:00
Daniel P. Berrangé
42a92ee93d network: add missing bandwidth limits for bridge forward type
In the case of a network with forward=bridge, which has a bridge device
listed, we are capable of setting bandwidth limits but fail to call the
function to register them.

Reviewed-by: Cole Robinson <crobinso@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-04-16 14:44:53 +01:00
Daniel P. Berrangé
bbe2aa627f conf: simplify link from hostdev back to network device
hostdevs have a link back to the original network device. This is fairly
generic accepting any type of device, however, we don't intend to make
use of this approach in future. It can thus be specialized to network
devices.

Reviewed-by: Cole Robinson <crobinso@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-04-16 14:44:53 +01:00
Daniel P. Berrangé
43c402aa16 network: drop back compat code loading actual bridge name
The actual network def was updated to save the bridge name back
in 1.2.11:

  commit a360912179
  Author: Laine Stump <laine@laine.org>
  Date:   Fri Nov 21 12:20:37 2014 -0500

    network: save bridge name in ActualNetDef when actualType==network too

The chance that someone is running libvirt < 1.2.11 and wants
todo a live upgrade to 5.3.0 without a host reboot is essentially
zero. We can thus reasonably drop the back compat code now.

Reviewed-by: Laine Stump <laine@laine.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-04-16 14:44:53 +01:00
Daniel P. Berrangé
e1d10f8ef2 network: pass a virNetworkPtr to port management APIs
The APIs for allocating/notifying/removing network ports just take
an internal domain interface struct right now. As a step towards
turning these into public facing APIs, add a virNetworkPtr argument
to all of them.

Reviewed-by: Cole Robinson <crobinso@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-04-16 14:44:53 +01:00
Daniel P. Berrangé
dd52444f23 network: restrict usage of port management APIs
The port allocation APIs are currently called unconditionally for all
types of NIC, but (mostly) only do anything for NICs with type=network.

The exception is the port allocate API which does some validation even
for NICs with type!=network. Relying on this validation is flawed,
however, since the network driver may not even be installed. IOW virt
drivers must not delegate validation to the network driver for NICs
with type != network.

This change allows us to report errors when the virtual network driver
is not registered.

Reviewed-by: Cole Robinson <crobinso@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-04-16 14:44:53 +01:00
Laine Stump
fc79e73836 network: only reload firewall after firewalld is finished restarting
The network driver used to reload the firewall rules whenever a dbus
NameOwnerChanged message for org.fedoraproject.FirewallD1 was
received. Presumably at some point in the past this was successful at
reloading our rules after a firewalld restart. Recently though I
noticed that once firewalld was restarted, libvirt's logs would get this
message:

  The name org.fedoraproject.FirewallD1 was not provided by any .service files

After this point, no networks could be started until libvirtd itself
was restarted.

The problem is that the NameOwnerChanged message is sent twice during
a firewalld restart - once when the old firewalld is stopped, and
again when the new firewalld is started. If we try to reload at the
point the old firewalld is stopped, none of the firewalld dbus calls
will succeed.

The solution is to check the new_owner field of the message - we
should reload our firewall rules only if new_owner is non-empty (it is
set to "" when firewalld is stopped, and some sort of epoch number
when it is again started).

Signed-off-by: Laine Stump <laine@laine.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2019-04-15 12:53:38 -04:00
Daniel P. Berrangé
c1c235eb5c network: clear cached error if we successfully create firewall chains
Since:

  commit 9f4e35dc73
  Author: Daniel P. Berrangé <berrange@redhat.com>
  Date:   Mon Mar 18 17:31:21 2019 +0000

    network: improve error report when firewall chain creation fails

We cache an error when failing to create the top level firewall chains.
This commit failed to account for fact that we may invoke
networkPreReloadFirewallRules() many times while libvirtd is running.
For example when firewalld is restarted.

When this happens the original failure may no longer occurr and we'll
successfully create our top level chains. We failed to clear the cached
error resulting in us failing to start virtual networks.

Reviewed-by: Laine Stump <laine@laine.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-04-15 17:08:47 +01:00
Andrea Bolognani
03a07357e1 maint: Add filetype annotations to Makefile.inc.am
Vim has trouble figuring out the filetype automatically because
the name doesn't follow existing conventions; annotations like
the ones we already have in Makefile.ci help it out.

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2019-04-12 16:55:38 +02:00
Cole Robinson
1d31526b52 Always put _LAST enums on second line of VIR_ENUM_IMPL
Standardize on putting the _LAST enum value on the second line
of VIR_ENUM_IMPL invocations. Later patches that add string labels
to VIR_ENUM_IMPL will push most of these to the second line anyways,
so this saves some noise.

Signed-off-by: Cole Robinson <crobinso@redhat.com>
2019-04-11 12:47:23 -04:00
Peter Krempa
f785318187 Revert "Include unistd.h directly by files using it"
This reverts commit a5e1602090.

Getting rid of unistd.h from our headers will require more work than
just fixing the broken mingw build. Revert it until I have a more
complete proposal.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
2019-04-10 12:26:32 +02:00
Peter Krempa
a5e1602090 Include unistd.h directly by files using it
util/virutil.h bogously included unistd.h. Drop it and replace it by
including it directly where needed.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-04-10 09:12:04 +02:00
Peter Krempa
285c5f28c4 util: Move enum convertors into virenum.(c|h)
virutil.(c|h) is a very gross collection of random code. Remove the enum
handlers from there so we can limit the scope where virtutil.h is used.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-04-10 09:12:04 +02:00
Daniel P. Berrangé
5d010c3df6 network: avoid trying to create global firewall rules if unprivileged
The unprivileged libvirtd does not have permission to create firewall
rules, or bridge devices, or do anything to the host network in
general. Historically we still activate the network driver though and
let the network start API call fail.

The startup code path which reloads firewall rules on active networks
would thus effectively be a no-op when unprivileged as it is impossible
for there to be any active networks

With the change to use a global set of firewall chains, however, we now
have code that is run unconditionally.

Ideally we would not register the network driver at all when
unprivileged, but the entanglement with the virt drivers currently makes
that impractical. As a temporary hack, we just make the firewall reload
into a no-op.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-03-19 10:03:02 +00:00
Daniel P. Berrangé
686803a1a2 network: split setup of ipv4 and ipv6 top level chains
During startup libvirtd creates top level chains for both ipv4
and ipv6 protocols. If this fails for any reason then startup
of virtual networks is blocked.

The default virtual network, however, only requires use of ipv4
and some servers have ipv6 disabled so it is expected that ipv6
chain creation will fail. There could equally be servers with
no ipv4, only ipv6.

This patch thus makes error reporting a little more fine grained
so that it works more sensibly when either ipv4 or ipv6 is
disabled on the server. Only the protocols that are actually
used by the virtual network have errors reported.

Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-03-19 10:01:53 +00:00
Daniel P. Berrangé
9f4e35dc73 network: improve error report when firewall chain creation fails
During startup we create some top level chains in which all
virtual network firewall rules will be placed. The upfront
creation is done to avoid slowing down creation of individual
virtual networks by checking for chain existance every time.

There are some factors which can cause this upfront creation
to fail and while a message will get into the libvirtd log
this won't be seen by users who later try to start a virtual
network. Instead they'll just get a message saying that the
libvirt top level chain does not exist. This message is
accurate, but unhelpful for solving the root cause.

This patch thus saves any error during daemon startup and
reports it when trying to create a virtual network later.

Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-03-19 09:54:52 +00:00
Andrea Bolognani
c0a4a98eab Fix names for abs_top_{src,build}dir variables
According to the official documentation for autoconf[1], the
correct names for these variables are abs_top_{src,build}dir
rather than abs_top{src,build}dir; in fact, we're already
using the correct names in various places, so let's just make
everything nice and consistent.

[1] https://www.gnu.org/software/autoconf/manual/autoconf-2.69/html_node/Preset-Output-Variables.html

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Martin Kletzander <mkletzan@redhat.com>
2019-03-14 10:05:28 +01:00
Michal Privoznik
fc380c2e01 Revert "virStateDriver - Separate AutoStart from Initialize"
https://bugzilla.redhat.com/show_bug.cgi?id=1685151

This reverts commit cefb97fb81.

The stateAutoStart callback will be removed in the next commit.
Therefore move autostarting of domains, networks and storage
pools back into stateInitialize callbacks.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-03-06 10:20:31 +01:00
Laine Stump
82fe58ff26 network: add netmask to dhcp range of dnsmasq conf file for IPv4
dnsmasq documentation says that the *IPv4* prefix/network
address/broadcast address sent to dhcp clients will be automatically
determined by dnsmasq by looking at the interface it's listening on,
so the original libvirt code did not add a netmask to the dnsmasq
commandline (or later, the dnsmasq conf file).

For *IPv6* however, dnsmasq apparently cannot automatically determine
the prefix (functionally the same as a netmask), and it must be
explicitly provided in the conf file (as a part of the dhcp-range
option). So many years after IPv4 DHCP support had been added, when
IPv6 dhcp support was added the prefix was included at the end of the
dhcp-range setting, but only for IPv6.

A user had reported a bug on a host where one of the interfaces was a
superset of the libvirt network where dhcp is needed (e.g., the host's
ethernet is 10.0.0.20/8, and the libvirt network is 10.10.0.1/24). For
some reason dnsmasq was supplying the netmask for the /8 network to
clients requesting an address on the /24 interface.

This seems like a bug in dnsmasq, but even if/when it gets fixed
there, it looks like there is no harm in just always adding the
netmask to all IPv4 dhcp-range options similar to how prefix is added
to all IPv6 dhcp-range options.

Signed-off-by: Laine Stump <laine@laine.org>
Reviewed-by: John Ferlan <jferlan@redhat.com>
2019-02-21 13:06:16 -05:00
Laine Stump
41adfe8ca9 network: explicitly allow icmp/icmpv6 in libvirt zonefile
The libvirt zonefile for firewalld (added in commit 3b71f2e4) does the
following:

1) lists specific services it wants to allow, then

2) uses a lower priority <reject/> rule to block all other services to
   the host, and then finally,

3) relies on the zone's default "accept" policy to, accept all
   forwarded traffic (since forwarded traffic is ignored by the
   slightly higher priority <reject/> rule in (2)).

I had assumed that icmp traffic was either being allowed at the top of
the rules, or that it would be ignored by the <reject/> rule and
passed by the default accept policy (similar to forwarded traffic),
but this assumption was incorrect; the <reject/> rule does block icmp
traffic. This became apparent when DHCPv6 which requires ICMPv6 in
addition to udp/dhcpv6) failed to work.

This all means that in order to achieve our original goal of "similar
behavior to a default reject policy, but also allowing forwarded
traffic", we need to add rules to allow all icmp and icmpv6 traffic to
the libvirt zone, and that's what this patch does.

This is a further refinement of the resolution to
https://bugzilla.redhat.com/1650320

Signed-off-by: Laine Stump <laine@laine.org>
Acked-by: Eric Garver <eric@garver.life>
2019-02-14 15:06:42 -05:00
Cole Robinson
6a4d938dd3 Require a semicolon for VIR_ENUM_IMPL calls
Missing semicolon at the end of macros can confuse some analyzers
(like cppcheck <filename>), and we have a mix of semicolon and
non-semicolon usage through the code. Let's standardize on using
a semicolon for VIR_ENUM_IMPL calls.

Move the verify() statement to the end of the macro and drop
the semicolon, so the compiler will require callers to add a
semicolon.

While we are touching these call sites, standardize on putting
the closing parenth on its own line, as discussed here:
https://www.redhat.com/archives/libvir-list/2019-January/msg00750.html

Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Cole Robinson <crobinso@redhat.com>
2019-02-03 17:46:29 -05:00
Laine Stump
30a6f91686 network: allow configuring firewalld zone for virtual network bridge device
Since we're setting the zone anyway, it will be useful to allow
setting a different (custom) zone for each network. This will be done
by adding a "zone" attribute to the "bridge" element, e.g.:

   ...
   <bridge name='virbr0' zone='myzone'/>
   ...

If a zone is specified in the config and it can't be honored, this
will be an error.

Signed-off-by: Laine Stump <laine@laine.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2019-02-01 12:57:13 -05:00
Laine Stump
ae05211a36 network: set firewalld zone of bridges to "libvirt" zone when appropriate
This patch restores broken guest network connectivity after a host
firewalld is switched to using an nftables backend. It does this by
adding libvirt networks' bridge interfaces to the new "libvirt" zone
in firewalld.

After this patch, the bridge interface of any network created by
libvirt (when firewalld is active) will be added to the firewalld
zone called "libvirt" if it exists (regardless of the firewalld
backend setting). This behavior does *not* depend on whether or not
libvirt has installed the libvirt zone file (set with
"--with[out]-firewalld-zone" during the configure phase of the package
build).

If the libvirt zone doesn't exist (either because the package was
configured to not install it, or possibly it was installed, but
firewalld doesn't support rule priorities, resulting in a parse
error), the bridge will remain in firewalld's default zone, which
could be innocuous (in the case that the firewalld backend is
iptables, guest networking will still function properly with the
bridge in the default zone), or it could be disastrous (if the
firewalld backend is nftables, we can be assured that guest networking
will fail). In order to be unobtrusive in the former case, and
informative in the latter, when the libvirt zone doesn't exist we
then check the firewalld version to see if it's new enough to support
the nftables backend, and then if the backend is actually set to
nftables, before logging an error (and failing the net-start
operation, since the network couldn't possibly work anyway).

When the libvirt zone is used, network behavior is *slightly*
different from behavior of previous libvirt. In the past, libvirt
network behavior would be affected by the configuration of firewalld's
default zone (usually "public"), but now it is affected only by the
"libvirt" zone), and thus almost surely warrants a release note for
any distro upgrading to libvirt 5.1 or above. Although it's
unfortunate that we have to deal with a mandatory behavior change, the
architecture of multiple hooks makes it impossible to *not* change
behavior in some way, and the new behavior is arguably better (since
it will now be possible to manage access to the host from virtual
machines vs from public interfaces separately).

Creates-and-Resolves: https://bugzilla.redhat.com/1650320
Resolves: https://bugzilla.redhat.com/1638342
Signed-off-by: Laine Stump <laine@laine.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2019-02-01 12:08:37 -05:00
Laine Stump
3b71f2e42d configure: selectively install a firewalld 'libvirt' zone
In the past (when both libvirt and firewalld used iptables), if either
libvirt's rules *OR* firewalld's rules accepted a packet, it would
be accepted. This was because libvirt and firewalld rules were
processed during the same kernel hook, and a single ACCEPT result
would terminate the rule traversal and cause the packet to be
accepted.

But now firewalld can use nftables for its backend, while libvirt's
firewall rules are still using iptables; iptables rules are still
processed, but at a different time during packet processing
(i.e. during a different hook) than the firewalld nftables rules. The
result is that a packet must be accepted by *BOTH* the libvirt
iptables rules *AND* the firewalld nftable rules in order to be
accepted.

This causes pain because

1) libvirt always adds rules to permit DNS and DHCP (and sometimes
TFTP) from guests to the host network's bridge interface. But
libvirt's bridges are in firewalld's "default" zone (which is usually
the zone called "public"). The public zone allows ssh, but doesn't
allow DNS, DHCP, or TFTP. So even though libvirt's rules allow the
DHCP and DNS traffic, the firewalld rules (now processed during a
different hook) dont, thus guests connected to libvirt's bridges can't
acquire an IP address from DHCP, nor can they make DNS queries to the
DNS server libvirt has setup on the host. (This could be solved by
modifying the default firewalld zone to allow DNS and DHCP, but that
would open *all* interfaces in the default zone to those services,
which is most likely not what the host's admin wants.)

2) Even though libvirt adds iptables rules to allow forwarded traffic
to pass the iptables hook, firewalld's higher level "rich rules" don't
yet have the ability to configure the acceptance of forwarded traffic
(traffic that is going somewhere beyond the host), so any traffic that
needs to be forwarded from guests to the network beyond the host is
rejected during the nftables hook by the default zone's "default
reject" policy (which rejects all traffic in the zone not specifically
allowed by the rules in the zone, whether that traffic is destined to
be forwarded or locally received by the host).

libvirt can't send "direct" nftables rules (firewalld only supports
direct/passthrough rules for iptables), so we can't solve this problem
by just sending explicit nftables rules instead of explicit iptables
rules (which, if it could be done, would place libvirt's rules in the
same hook as firewalld's native rules, and thus eliminate the need for
packets to be accepted by both libvirt's and firewalld's own rules).

However, we can take advantage of a quirk in firewalld zones that have
a default policy of "accept" (meaning any packet that doesn't match a
specific rule in the zone will be *accepted*) - this default accept will
also accept forwarded traffic (not just traffic destined for the host).

Of course we don't want to modify firewalld's default zone in that
way, because that would affect the filtering of traffic coming into
the host from other interfaces using that zone. Instead, we will
create a new zone called "libvirt". The libvirt zone will have a
default policy of accept so that forwarded traffic can pass and list
specific services that will be allowed into the host from guests (DNS,
DHCP, SSH, and TFTP).

But the same default accept policy that fixes forwarded traffic also
causes *all* traffic from guest to host to be accepted. To close this
new hole, the libvirt zone can take advantage of a new feature in
firewalld (currently slated for firewalld-0.7.0) - priorities for rich
rules - to add a low priority rule that rejects all local traffic (but
leaves alone all forwarded traffic).

So, our new zone will start with a list of services that are allowed
(dhcp, dns, tftp, and ssh to start, but configurable via any firewalld
management application, or direct editing of the zone file in
/etc/firewalld/zones/libvirt.xml), followed by a low priority
<reject/> rule (to reject all other traffic from guest to host), and
finally with a default policy of accept (to allow forwarded traffic).

This patch only creates the zonefile for the new zone, and implements
a configure.ac option to selectively enable/disable installation of
the new zone. A separate patch contains the necessary code to actually
place bridge interfaces in the libvirt zone.

Why do we need a configure option to disable installation of the new
libvirt zone? It uses a new firewalld attribute that sets the priority
of a rich rule; this feature first appears in firewalld-0.7.0 (unless
it has been backported to am earlier firewalld by a downstream
maintainer). If the file were installed on a system with firewalld
that didn't support rule priorities, firewalld would log an error
every time it restarted, causing confusion and lots of extra bug
reports.

So we add two new configure.ac switches to avoid polluting the system
logs with this error on systems that don't support rule priorities -
"--with-firewalld-zone" and "--without-firewalld-zone". A package
builder can use these to include/exclude the libvirt zone file in the
installation. If firewalld is enabled (--with-firewalld), the default
is --with-firewalld-zone, but it can be disabled during configure
(using --without-firewalld-zone). Targets that are using a firewalld
version too old to support the rule priority setting in the libvirt
zone file can simply add --without-firewalld-zone to their configure
commandline.

These switches only affect whether or not the libvirt zone file is
*installed* in /usr/lib/firewalld/zones, but have no effect on whether
or not libvirt looks for a zone called libvirt and tries to use it.

NB: firewalld zones can only be added to the permanent config of
firewalld, and won't be loaded/enabled until firewalld is restarted,
so at package install/upgrade time we have to restart firewalld. For
rpm-based distros, this is done in the libvirt.spec file by calling
the %firewalld_restart rpm macro, which is a part of the
firewalld-filesystem package. (For distros that don't use rpm
packages, the command "firewalld-cmd --reload" will have the same
effect).

Signed-off-by: Laine Stump <laine@laine.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2019-02-01 12:08:37 -05:00
Laine Stump
4bf0f390ed configure: change HAVE_FIREWALLD to WITH_FIREWALLD
Support for firewalld is a feature that can be selectively enabled or
disabled (using --with-firewalld/--without-firewalld), not merely
something that must be accounted for in the code if it is present with
no exceptions. It is more consistent with other usage in libvirt to
use WITH_FIREWALLD rather than HAVE_FIREWALLD.

Signed-off-by: Laine Stump <laine@laine.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2019-02-01 12:08:37 -05:00
Casey Callendrello
682be11505 network: set mtu as a DHCP option when specified
This adds an additional directive to the dnsmasq configuration file that
notifies clients via dhcp about the link's MTU. Guests can then choose
adjust their link accordingly.

Signed-off-by: Casey Callendrello <cdc@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Ján Tomko <jtomko@redhat.com>
2019-01-31 17:45:41 +01:00
Daniel P. Berrangé
7431b3eb9a util: move virtual network firwall rules into private chains
The previous commit created new chains to hold the firewall rules. This
commit changes the code that creates rules to place them in the new
private chains instead of the builtin top level chains.

With two networks running, the rules in the filter table now look like

  -N LIBVIRT_FWI
  -N LIBVIRT_FWO
  -N LIBVIRT_FWX
  -N LIBVIRT_INP
  -N LIBVIRT_OUT
  -A INPUT -j LIBVIRT_INP
  -A FORWARD -j LIBVIRT_FWX
  -A FORWARD -j LIBVIRT_FWI
  -A FORWARD -j LIBVIRT_FWO
  -A OUTPUT -j LIBVIRT_OUT
  -A LIBVIRT_FWI -d 192.168.0.0/24 -o virbr0 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
  -A LIBVIRT_FWI -o virbr0 -j REJECT --reject-with icmp-port-unreachable
  -A LIBVIRT_FWI -d 192.168.1.0/24 -o virbr1 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
  -A LIBVIRT_FWI -o virbr1 -j REJECT --reject-with icmp-port-unreachable
  -A LIBVIRT_FWO -s 192.168.0.0/24 -i virbr0 -j ACCEPT
  -A LIBVIRT_FWO -i virbr0 -j REJECT --reject-with icmp-port-unreachable
  -A LIBVIRT_FWO -s 192.168.1.0/24 -i virbr1 -j ACCEPT
  -A LIBVIRT_FWO -i virbr1 -j REJECT --reject-with icmp-port-unreachable
  -A LIBVIRT_FWX -i virbr0 -o virbr0 -j ACCEPT
  -A LIBVIRT_FWX -i virbr1 -o virbr1 -j ACCEPT
  -A LIBVIRT_INP -i virbr0 -p udp -m udp --dport 53 -j ACCEPT
  -A LIBVIRT_INP -i virbr0 -p tcp -m tcp --dport 53 -j ACCEPT
  -A LIBVIRT_INP -i virbr0 -p udp -m udp --dport 67 -j ACCEPT
  -A LIBVIRT_INP -i virbr0 -p tcp -m tcp --dport 67 -j ACCEPT
  -A LIBVIRT_INP -i virbr1 -p udp -m udp --dport 53 -j ACCEPT
  -A LIBVIRT_INP -i virbr1 -p tcp -m tcp --dport 53 -j ACCEPT
  -A LIBVIRT_INP -i virbr1 -p udp -m udp --dport 67 -j ACCEPT
  -A LIBVIRT_INP -i virbr1 -p tcp -m tcp --dport 67 -j ACCEPT
  -A LIBVIRT_OUT -o virbr0 -p udp -m udp --dport 68 -j ACCEPT
  -A LIBVIRT_OUT -o virbr1 -p udp -m udp --dport 68 -j ACCEPT

While in the nat table:

  -N LIBVIRT_PRT
  -A POSTROUTING -j LIBVIRT_PRT
  -A LIBVIRT_PRT -s 192.168.0.0/24 -d 224.0.0.0/24 -j RETURN
  -A LIBVIRT_PRT -s 192.168.0.0/24 -d 255.255.255.255/32 -j RETURN
  -A LIBVIRT_PRT -s 192.168.0.0/24 ! -d 192.168.0.0/24 -p tcp -j MASQUERADE --to-ports 1024-65535
  -A LIBVIRT_PRT -s 192.168.0.0/24 ! -d 192.168.0.0/24 -p udp -j MASQUERADE --to-ports 1024-65535
  -A LIBVIRT_PRT -s 192.168.0.0/24 ! -d 192.168.0.0/24 -j MASQUERADE
  -A LIBVIRT_PRT -s 192.168.1.0/24 -d 224.0.0.0/24 -j RETURN
  -A LIBVIRT_PRT -s 192.168.1.0/24 -d 255.255.255.255/32 -j RETURN
  -A LIBVIRT_PRT -s 192.168.1.0/24 ! -d 192.168.1.0/24 -p tcp -j MASQUERADE --to-ports 1024-65535
  -A LIBVIRT_PRT -s 192.168.1.0/24 ! -d 192.168.1.0/24 -p udp -j MASQUERADE --to-ports 1024-65535
  -A LIBVIRT_PRT -s 192.168.1.0/24 ! -d 192.168.1.0/24 -j MASQUERADE

And finally the mangle table:

  -N LIBVIRT_PRT
  -A POSTROUTING -j LIBVIRT_PRT
  -A LIBVIRT_PRT -o virbr0 -p udp -m udp --dport 68 -j CHECKSUM --checksum-fill
  -A LIBVIRT_PRT -o virbr1 -p udp -m udp --dport 68 -j CHECKSUM --checksum-fill

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-01-29 13:37:11 +00:00
Daniel P. Berrangé
5f1e6a7d48 util: create private chains for virtual network firewall rules
Historically firewall rules for virtual networks were added straight
into the base chains. This works but has a number of bugs and design
limitations:

  - It is inflexible for admins wanting to add extra rules ahead
    of libvirt's rules, via hook scripts.

  - It is not clear to the admin that the rules were created by
    libvirt

  - Each rule must be deleted by libvirt individually since they
    are all directly in the builtin chains

  - The ordering of rules in the forward chain is incorrect
    when multiple networks are created, allowing traffic to
    mistakenly flow between networks in one direction.

To address all of these problems, libvirt needs to move to creating
rules in its own private chains. In the top level builtin chains,
libvirt will add links to its own private top level chains.

Addressing the traffic ordering bug requires some extra steps. With
everything going into the FORWARD chain there was interleaving of rules
for outbound traffic and inbound traffic for each network:

  -A FORWARD -d 192.168.3.0/24 -o virbr1 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
  -A FORWARD -s 192.168.3.0/24 -i virbr1 -j ACCEPT
  -A FORWARD -i virbr1 -o virbr1 -j ACCEPT
  -A FORWARD -o virbr1 -j REJECT --reject-with icmp-port-unreachable
  -A FORWARD -i virbr1 -j REJECT --reject-with icmp-port-unreachable
  -A FORWARD -d 192.168.2.0/24 -o virbr0 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
  -A FORWARD -s 192.168.2.0/24 -i virbr0 -j ACCEPT
  -A FORWARD -i virbr0 -o virbr0 -j ACCEPT
  -A FORWARD -o virbr0 -j REJECT --reject-with icmp-port-unreachable
  -A FORWARD -i virbr0 -j REJECT --reject-with icmp-port-unreachable

The rule allowing outbound traffic from virbr1 would mistakenly
allow packets from virbr1 to virbr0, before the rule denying input
to virbr0 gets a chance to run.

What we really need todo is group the forwarding rules into three
distinct sets:

 * Cross rules - LIBVIRT_FWX

  -A FORWARD -i virbr1 -o virbr1 -j ACCEPT
  -A FORWARD -i virbr0 -o virbr0 -j ACCEPT

 * Incoming rules - LIBVIRT_FWI

  -A FORWARD -d 192.168.3.0/24 -o virbr1 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
  -A FORWARD -o virbr1 -j REJECT --reject-with icmp-port-unreachable
  -A FORWARD -d 192.168.2.0/24 -o virbr0 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
  -A FORWARD -o virbr0 -j REJECT --reject-with icmp-port-unreachable

 * Outgoing rules - LIBVIRT_FWO

  -A FORWARD -s 192.168.3.0/24 -i virbr1 -j ACCEPT
  -A FORWARD -i virbr1 -j REJECT --reject-with icmp-port-unreachable
  -A FORWARD -s 192.168.2.0/24 -i virbr0 -j ACCEPT
  -A FORWARD -i virbr0 -j REJECT --reject-with icmp-port-unreachable

There is thus no risk of outgoing rules for one network mistakenly
allowing incoming traffic for another network, as all incoming rules
are evalated first.

With this in mind, we'll thus need three distinct chains linked from
the FORWARD chain, so we end up with:

        INPUT --> LIBVIRT_INP   (filter)

       OUTPUT --> LIBVIRT_OUT   (filter)

      FORWARD +-> LIBVIRT_FWX   (filter)
              +-> LIBVIRT_FWO
              \-> LIBVIRT_FWI

  POSTROUTING --> LIBVIRT_PRT   (nat & mangle)

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-01-29 13:35:58 +00:00
Daniel P. Berrangé
0fc746aa54 network: add platform driver callbacks around firewall reload
Allow the platform driver impls to run logic before and after the
firewall reload process.

Reviewed-by: Laine Stump <laine@laine.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2019-01-29 13:35:58 +00:00
Laine Stump
43be65a481 network: remove stale function
networkMigrateStateFiles was added nearly 5 years ago when the network
state directory was moved from /var/lib/libvirt to /var/run/libvirt
just prior to libvirt-1.2.4). It was only required to maintain proper
state information for networks that were active during an upgrade that
didn't involve rebooting the host. At this point the likelyhood of
anyone upgrading their libvirt from pre-1.2.4 directly to 5.0.0 or
later *without rebooting the host* is probably so close to 0 that no
properly informed bookie would take *any* odds on it happening, so it
seems appropriate to remove this pointless code.

Signed-off-by: Laine Stump <laine@laine.org>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
2019-01-25 11:01:05 -05:00
Daniel P. Berrangé
568a417224 Enforce a standard header file guard symbol name
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>
2018-12-14 10:47:13 +00:00