iptablesContext holds only 4 pairs of iptables
(table, chain) and there's no need to pass
it around.

This is a first step towards separating bridge_driver.c
in platform-specific parts.

These all existed before virfile.c was created, and for some reason
weren't moved.

This is mostly straightfoward, although the syntax rule prohibiting
write() had to be changed to have an exception for virfile.c instead
of virutil.c.

This movement pointed out that there is a function called
virBuildPath(), and another almost identical function called
virFileBuildPath(). They really should be a single function, which
I'll take care of as soon as I figure out what the arglist should look
like.

The source code base needs to be adapted as well. Some files
include virutil.h just for the string related functions (here,
the include is substituted to match the new file), some include
virutil.h without any need (here, the include is removed), and
some require both.

iptables-1.4.18 removed the long deprecated "state" match.
Use "conntrack" instead in forwarding rules.
Fixes openSUSE bug https://bugzilla.novell.com/811251 #811251.

We pass over the address/port start/end values many times so we put
them in structs.
Signed-off-by: NNatanael Copa <ncopa@alpinelinux.org>
Signed-off-by: NLaine Stump <laine@laine.org>

Let users set the port range to be used for forward mode NAT:

...
  <forward mode='nat'>
    <nat>
      <port start='1024' end='65535'/>
    </nat>
  </forward>
...
Signed-off-by: NNatanael Copa <ncopa@alpinelinux.org>
Signed-off-by: NLaine Stump <laine@laine.org>

Support setting which public ip to use for NAT via attribute
address in subelement <nat> in <forward>:

...
  <forward mode='nat'>
      <address start='1.2.3.4' end='1.2.3.10'/>
  </forward>
...

This will construct an iptables line using:

  '-j SNAT --to-source <start>-<end>'

instead of:

  '-j MASQUERADE'
Signed-off-by: NNatanael Copa <ncopa@alpinelinux.org>
Signed-off-by: NLaine Stump <laine@laine.org>

Instead of creating an iptables command in one shot, do it in steps
so we can add conditional options like physdev and protocol.

This removes code duplication while keeping existing behaviour.
Signed-off-by: NNatanael Copa <ncopa@alpinelinux.org>
Signed-off-by: NEric Blake <eblake@redhat.com>

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/

Several VIR_DEBUG()'s were changed to VIR_WARN() while I was testing
the firewalld support patch, and I neglected to change them back
before I pushed.

In the meantime I've decided that it would be useful to have them be
VIR_INFO(), just so there will be logged evidence of which method is
being used (firewall-cmd vs. (eb|ip)tables) without needing to crank
logging to 11. (at most this adds 2 lines to libvirtd's logs per
libvirtd start).

* configure.ac, spec file: firewalld defaults to enabled if dbus is
  available, otherwise is disabled. If --with_firewalld is explicitly
  requested and dbus is not available, configure will fail.

* bridge_driver: add dbus filters to get the FirewallD1.Reloaded
  signal and DBus.NameOwnerChanged on org.fedoraproject.FirewallD1.
  When these are encountered, reload all the iptables reuls of all
  libvirt's virtual networks (similar to what happens when libvirtd is
  restarted).

* iptables, ebtables: use firewall-cmd's direct passthrough interface
  when available, otherwise use iptables and ebtables commands. This
  decision is made once the first time libvirt calls
  iptables/ebtables, and that decision is maintained for the life of
  libvirtd.

* Note that the nwfilter part of this patch was separated out into
  another patch by Stefan in V2, so that needs to be revised and
  re-reviewed as well.

================

All the configure.ac and specfile changes are unchanged from Thomas'
V3.

V3 re-ran "firewall-cmd --state" every time a new rule was added,
which was extremely inefficient.  V4 uses VIR_ONCE_GLOBAL_INIT to set
up a one-time initialization function.

The VIR_ONCE_GLOBAL_INIT(x) macro references a static function called
vir(Ip|Eb)OnceInit(), which will then be called the first time that
the static function vir(Ip|Eb)TablesInitialize() is called (that
function is defined for you by the macro). This is
thread-safe, so there is no chance of any race.

IMPORTANT NOTE: I've left the VIR_DEBUG messages in these two init
functions (one for iptables, on for ebtables) as VIR_WARN so that I
don't have to turn on all the other debug message just to see
these. Even if this patch doesn't need any other modification, those
messages need to be changed to VIR_DEBUG before pushing.

This one-time initialization works well. However, I've encountered
problems with testing:

1) Whenever I have enabled the firewalld service, *all* attempts to
call firewall-cmd from within libvirtd end with firewall-cmd hanging
internally somewhere. This is *not* the case if firewall-cmd returns
non-0 in response to "firewall-cmd --state" (i.e. *that* command runs
and returns to libvirt successfully.)

2) If I start libvirtd while firewalld is stopped, then start
firewalld later, this triggers libvirtd to reload its iptables rules,
however it also spits out a *ton* of complaints about deletion failing
(I suppose because firewalld has nuked all of libvirt's rules). I
guess we need to suppress those messages (which is a more annoying
problem to fix than you might think, but that's another story).

3) I noticed a few times during this long line of errors that
firewalld made a complaint about "Resource Temporarily
unavailable. Having libvirtd access iptables commands directly at the
same time as firewalld is doing so is apparently problematic.

4) In general, I'm concerned about the "set it once and never change
it" method - if firewalld is disabled at libvirtd startup, causing
libvirtd to always use iptables/ebtables directly, this won't cause
*terrible* problems, but if libvirtd decides to use firewall-cmd and
firewalld is later disabled, libvirtd will not be able to recover.

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

This removes nearly all the per-file error reporting macros
from the code in src/util/. A few custom macros remain for the
case, where the file needs to report errors with a variety of
different codes or parameters
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

https://bugzilla.redhat.com/show_bug.cgi?id=648855 mentioned a
misuse of 'an' where 'a' is proper; that has since been fixed,
but a search found other problems (some were a spelling error for
'and', while most were fixed by 'a').

* daemon/stream.c: Fix grammar.
* src/conf/domain_conf.c: Likewise.
* src/conf/domain_event.c: Likewise.
* src/esx/esx_driver.c: Likewise.
* src/esx/esx_vi.c: Likewise.
* src/rpc/virnetclient.c: Likewise.
* src/rpc/virnetserverprogram.c: Likewise.
* src/storage/storage_backend_fs.c: Likewise.
* src/util/conf.c: Likewise.
* src/util/dnsmasq.c: Likewise.
* src/util/iptables.c: Likewise.
* src/xen/xen_hypervisor.c: Likewise.
* src/xen/xend_internal.c: Likewise.
* src/xen/xs_internal.c: Likewise.
* tools/virsh.c: Likewise.

The socket address APIs in src/util/network.h either take the
form  virSocketAddrXXX, virSocketXXX or virSocketXXXAddr.

Sanitize this so everything is virSocketAddrXXXX, and ensure
that the virSocketAddr parameter is always the first one.

* src/util/network.c, src/util/network.h: Santize socket
  address API naming
* src/conf/domain_conf.c, src/conf/network_conf.c,
  src/conf/nwfilter_conf.c, src/network/bridge_driver.c,
  src/nwfilter/nwfilter_ebiptables_driver.c,
  src/nwfilter/nwfilter_learnipaddr.c,
  src/qemu/qemu_command.c, src/rpc/virnetsocket.c,
  src/util/dnsmasq.c, src/util/iptables.c,
  src/util/virnetdev.c, src/vbox/vbox_tmpl.c: Update for
  API renaming

And from all related macros and functions.

Although the upper-layer code protected against it, it was possible to
call iptablesForwardMasquerade() with an IPv6 address and have it
attempt to add a rule to the MASQUERADE chain of ip6tables (which
doesn't exist).

This patch changes that function to check the protocol of the given
address, generate an error log if it's not IPv4 (AF_INET), and finally
hardcodes all the family parameters sent down to lower-level functions.

The original version of these functions would modify the address sent
in, meaning that the caller would usually need to copy the address
first. This change makes the original a const, and puts the resulting
masked address into a new arg (which could point to the same
virSocketAddr as the original, if the caller really wants to modify
it).

This also makes the API consistent with virSocketAddrBroadcast[ByPrefix].

All of the iptables functions eventually call down to a single
bottom-level function, and fortunately, ip6tables syntax (for all the
args that we use) is identical to iptables format (except the
addresses), so all we need to do is:

1) Get an address family down to the lowest level function in each
   case, either implied through an address, or explicitly when no
   address is in the parameter list, and

2) At the lowest level, just decide whether to call "iptables" or
   "ip6tables" based on the family.

The location of the ip6tables binary is determined at build time by
autoconf. If a particular target system happens to not have ip6tables
installed, any attempts to run it will generate an error, but that
won't happen unless someone tries to define an IPv6 address for a
network. This is identical behavior to IPv4 addresses and iptables.

IPv6 will use prefix exclusively, and IPv4 will also optionally be
able to use it, and the iptables functions really need a prefix
anyway, so use the new virNetworkDefPrefix() function to send prefixes
into iptables functions instead of netmasks.

Also, in a couple places where a netmask is actually needed, use the
new private API function for it rather than getting it directly. This
will allow for cases where no netmask or prefix is specified (it
returns the default for the current class of network.)

This proof of concept shows how two existing uses of virExec
and virRun can be ported to the new virCommand APIs, and how
much simpler the code becomes

They only popped up during --disable-nls build. Without this configure
option, gcc wasn't able to detect them.

The network address was being set to 192.168.122.0 instead
of 192.168.122.0/24. Fix this by removing the unneccessary
'network' field from virNetworkDef and just pass the
network address and netmask into the iptables APIs directly.

* src/conf/network_conf.h, src/conf/network_conf.c: Remove
  the 'network' field from virNEtworkDef.
* src/network/bridge_driver.c: Update for iptables API changes
* src/util/iptables.c, src/util/iptables.h: Require the
  network address + netmask pair to be passed in

Instead of storing the IP address string in virNetwork related
structs, store the parsed virSocketAddr. This will make it
easier to add IPv6 support in the future, by letting driver
code directly check what address family is present

* src/conf/network_conf.c, src/conf/network_conf.h,
  src/network/bridge_driver.c: Convert to use virSocketAddr
  in virNetwork, instead of char *.
* src/util/bridge.c, src/util/bridge.h,
  src/util/dnsmasq.c, src/util/dnsmasq.h,
  src/util/iptables.c, src/util/iptables.h: Convert to
  take a virSocketAddr instead of char * for any IP
  address parameters
* src/util/network.h: Add macros to determine if an address
  is set, and what address family is set.

This patch attempts to take advantage of a newly added netfilter
module to correct for a problem with some guest DHCP client
implementations when used in conjunction with a DHCP server run on the
host systems with packet checksum offloading enabled.

The problem is that, when the guest uses a RAW socket to read the DHCP
response packets, the checksum hasn't yet been fixed by the IP stack,
so it is incorrect.

The fix implemented here is to add a rule to the POSTROUTING chain of
the mangle table in iptables that fixes up the checksum for packets on
the virtual network's bridge that are destined for the bootpc port (ie
"dhcpc", ie port 68) port on the guest.

Only very new versions of iptables will have this support (it will be
in the next upstream release), so a failure to add this rule only
results in a warning message. The iptables patch is here:

  http://patchwork.ozlabs.org/patch/58525/

A corresponding kernel module patch is also required (the backend of
the iptables patch) and that will be in the next release of the
kernel.

IPtables will seek to preserve the source port unchanged when
doing masquerading, if possible. NFS has a pseudo-security
option where it checks for the source port <= 1023 before
allowing a mount request. If an admin has used this to make the
host OS trusted for mounts, the default iptables behaviour will
potentially allow NAT'd guests access too. This needs to be
stopped.

With this change, the iptables -t nat -L -n -v rules for the
default network will be

Chain POSTROUTING (policy ACCEPT 95 packets, 9163 bytes)
 pkts bytes target     prot opt in     out     source               destination
   14   840 MASQUERADE  tcp  --  *      *       192.168.122.0/24    !192.168.122.0/24    masq ports: 1024-65535
   75  5752 MASQUERADE  udp  --  *      *       192.168.122.0/24    !192.168.122.0/24    masq ports: 1024-65535
    0     0 MASQUERADE  all  --  *      *       192.168.122.0/24    !192.168.122.0/24

* src/network/bridge_driver.c: Add masquerade rules for TCP
  and UDP protocols
* src/util/iptables.c, src/util/iptables.c: Add source port
  mappings for TCP & UDP protocols when masquerading.

* src/util/ebtables.c (ebtablesAddRemoveRule): Don't skip
va_end(args) on an error path.
* src/util/iptables.c (iptablesAddRemoveRule): Identical change.

* configure.ac: Drop sys/wait.h check.
* src/libvirt.c (includes): Use header unconditionally.
* src/remote/remote_driver.c (includes): Likewise.
* src/storage/storage_backend.c (includes): Likewise.
* src/util/ebtables.c (includes): Likewise.
* src/util/hooks.c (includes): Likewise.
* src/util/iptables.c (includes): Likewise.
* src/util/util.c (includes): Likewise.

* global: patch created by running:
for f in $(git ls-files '*.[ch]') ; do
    cppi $f > $f.t && mv $f.t $f
done

It was used for error reporting only.

We don't use this method of reloading rules anymore, so we can just
kill the code.

This simplifies things a lot because we no longer need to keep a
table of the rules we've added.

* src/util/iptables.c: kill iptablesReloadRules()

Long ago we tried to use Fedora's lokkit utility in order to register
our iptables rules so that 'service iptables restart' would
automatically load our rules.

There was one fatal flaw - if the user had configured iptables without
lokkit, then we would clobber that configuration by running lokkit.

We quickly disabled lokkit support, but never removed it. Let's do
that now.

The 'my virtual network stops working when I restart iptables' still
remains. For all the background on this saga, see:

  https://bugzilla.redhat.com/227011

* src/util/iptables.c: remove lokkit support

* configure.in: remove --enable-lokkit

* libvirt.spec.in: remove the dirs used only for saving rules for lokkit

* src/Makefile.am: ditto

* src/libvirt_private.syms, src/network/bridge_driver.c,
  src/util/iptables.h: remove references to iptablesSaveRules

* src/util/iptables.c: `--option !  this` is deprecated in favor of
  `! --option this` syntax, change the output command accordingly