When firewalld is stopped, it removes *all* iptables rules and chains,
including those added by libvirt. Since restarting firewalld means
stopping and then starting it, any time it is restarted, libvirt needs
to recreate all the private iptables chains it uses, along with all
the rules it adds.
We already have code in place to call networkReloadFirewallRules() any
time we're notified of a firewalld start, and
networkReloadFirewallRules() will call
networkPreReloadFirewallRules(), which calls
networkSetupPrivateChains(); unfortunately that last call is called
using virOnce(), meaning that it will only be called the first time
through networkPreReloadFirewallRules() after libvirtd starts - so of
course when firewalld is later restarted, the call to
networkSetupPrivateChains() is skipped.
The neat and tidy way to fix this would be if there was a standard way
to reset a pthread_once_t object so that the next time virOnce was
called, it would think the function hadn't been called, and call it
again. Unfortunately, there isn't any official way of doing that (we
*could* just fill it with 0 and hope for the best, but that doesn't
seem very safe.
So instead, this patch just adds a static variable called
chainInitDone, which is set to true after networkSetupPrivateChains()
is called for the first time, and then during calls to
networkPreReloadFirewallRules(), if chainInitDone is set, we call
networkSetupPrivateChains() directly instead of via virOnce().
It may seem unsafe to directly call a function that is meant to be
called only once, but I think in this case we're safe - there's
nothing in the function that is inherently "once only" - it doesn't
initialize anything that can't safely be re-initialized (as long as
two threads don't try to do it at the same time), and it only happens
when responding to a dbus message that firewalld has been started (and
I don't think it's possible for us to be processing two of those at
once), and even then only if the initial call to the function has
already been completed (so we're safe if we receive a firewalld
restart call at a time when we haven't yet called it, or even if
another thread is already in the process of executing it. The only
problematic bit I can think of is if another thread is in the process
of adding an iptable rule at the time we're executing this function,
but 1) none of those threads will be trying to add chains, and 2) if
there was a concurrency problem with other threads adding iptables
rules while firewalld was being restarted, it would still be a problem
even without this change.
This is yet another patch that fixes an occurrence of this error:
COMMAND_FAILED: '/usr/sbin/iptables -w10 -w --table filter --insert LIBVIRT_INP --in-interface virbr0 --protocol tcp --destination-port 67 --jump ACCEPT' failed: iptables: No chain/target/match by that name.
In particular, this resolves: https://bugzilla.redhat.com/1813830
Signed-off-by: Laine Stump <laine@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Use G_GNUC_UNUSED from GLib instead of ATTRIBUTE_UNUSED.
Signed-off-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
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>
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>
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>
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>
The networkCheckRouteCollision, networkAddFirewallRules and
networkRemoveFirewallRules APIs all take a virNetworkObjPtr
instance, but only ever access the 'def' member. It thus
simplifies testing if the APIs are changed to just take a
virNetworkDefPtr instead
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
The bridge_driver_platform.h defines many functions that
a platform driver must implement. Only two of these
functions are actually called from the main bridge driver
code. The remainder can be made internal to the linux
driver only.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
* Move platform specific things (e.g. firewalling and route
collision checks) into bridge_driver_platform
* Create two platform specific implementations:
- bridge_driver_linux: Linux implementation using iptables,
it's actually the code moved from bridge_driver.c
- bridge_driver_nop: dumb implementation that does nothing
Signed-off-by: Eric Blake <eblake@redhat.com>
