[libvirt] [PATCH 1/3] network: new network forward mode 'open'

[Daniel P. Berrange]

On Thu, Aug 11, 2016 at 10:41:45PM -0400, Laine Stump wrote:
> The new forward mode 'open' is just like mode='route', except that no
> firewall rules are added to assure that any traffic does or doesn't
> pass. It is assumed that either they aren't necessary, or they will be
> setup outside the scope of libvirt.
> 
> Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=846810
> ---
>  docs/formatnetwork.html.in                         | 22 ++++++++++++
>  docs/schemas/network.rng                           |  1 +
>  src/conf/network_conf.c                            | 25 +++++++++++--
>  src/conf/network_conf.h                            |  1 +
>  src/network/bridge_driver.c                        | 41 +++++++++++++++-------
>  tests/networkxml2confdata/open-network.conf        | 11 ++++++
>  tests/networkxml2confdata/open-network.xml         |  9 +++++
>  tests/networkxml2conftest.c                        |  1 +
>  .../open-network-with-forward-dev.xml              |  9 +++++
>  tests/networkxml2xmlin/open-network.xml            |  9 +++++
>  tests/networkxml2xmlout/open-network.xml           |  9 +++++
>  tests/networkxml2xmltest.c                         |  2 ++
>  12 files changed, 125 insertions(+), 15 deletions(-)
>  create mode 100644 tests/networkxml2confdata/open-network.conf
>  create mode 100644 tests/networkxml2confdata/open-network.xml
>  create mode 100644 tests/networkxml2xmlin/open-network-with-forward-dev.xml
>  create mode 100644 tests/networkxml2xmlin/open-network.xml
>  create mode 100644 tests/networkxml2xmlout/open-network.xml
> 
> diff --git a/docs/formatnetwork.html.in b/docs/formatnetwork.html.in
> index a9226e5..12d1bed 100644
> --- a/docs/formatnetwork.html.in
> +++ b/docs/formatnetwork.html.in
> @@ -260,6 +260,28 @@
>              <span class="since">Since 0.4.2</span>
>            </dd>
>  
> +          <dt><code>open</code></dt>
> +          <dd>
> +            As with mode='route', guest network traffic will be
> +            forwarded to the physical network via the host's IP
> +            routing stack, but there will be no firewall rules added
> +            to either enable or prevent any of this traffic. When
> +            forward='open' is set, the <code>dev</code> attribute
> +            cannot be set (because the forward dev is enforced with
> +            firewall rules, and the purpose of forward='open' is to
> +            have a forwarding mode where libvirt doesn't add any
> +            firewall rules).  This mode presumes that the local LAN
> +            router has suitable routing table entries to return
> +            traffic to this host, and that some other management
> +            system has been used to put in place any necessary
> +            firewall rules. Although no firewall rules will be added
> +            for the network, it is of course still possible to add
> +            restrictions for specific guests using
> +            <a href="formatnwfilter.html">nwfilter rules</a> on the
> +            guests' interfaces.)
> +            <span class="since">Since 2.2.0</span>
> +          </dd>
> +

Isn't this basically the same as forward mode="bridge", except that
we still create the bridge ourselves, instead of requiring it to be
pre-created ?

If so, I wonder if its better add a attribute 'create=yes|no' to
the <bridge> element instead ?


Regards,
Daniel
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