[libvirt] [PATCH-v4 2/2] Support for static routes on a virtual bridge

Laine Stump laine at laine.org
Mon Apr 22 15:59:07 UTC 2013


(I had thought there would be just a few tweaks to the documentation
that I could squash in and push, but as I reviewed I found more issues,
and don't have time to fix them myself. It is *very* close though, and
the freeze for 1.0.5 is coming up (within a couple days, I think?), so
if you can make the changes below, maybe we can get this into 1.0.5.)

On 04/20/2013 03:45 PM, Gene Czarcinski wrote:
> Support for static routes on a virtual bridge
> This patch adds support for adding a static route for
> a network.  The "gateway" sub-element specifies
> the gateway's IP address.  Both IPv4 and IPv6
> static routes are supported although it is
> expected that this functionality will have
> more use with IPv6.
>
> This updates add the <route> element to define a
> static route.  The gateway= subelement species the
> gateway address which is to receive the packets
> forwarded to the network specified on the
> <route> definition.

The first two paragraphs are nearly equivalent, and their first
sentences are also redundant with the first line of the comment. I've
merged them into a single, more succinct introduction.
(btw, note that "gateway" is an attribute, not a subelement):


network: static route support for <network>

This patch adds the <route> subelement of <network> to define a static
route.  the address and prefix (or netmask) attribute identify the
destination network, and the gateway attribute specifies the next hop
address (which must be directly reachable from the containing
<network>) which is to receive the packets destined for
"adress/(prefix|netmask)".


>
> Tests are done to validate that the input definitions are
> correct.  For example, for a static route ip definition,
> the address must be a network address and not a host address.
> Additional checks are added to ensure that the specified gateway
> is directly reachable via a network defined on this bridge.
>
> Whan a static route is added to a bridge, there is a slight
> possibility that the gateway address will be incorrect.  If
> this is handled as an error, that bridge becomes unusable and
> can only be recovered by rebooting.  If the error is
> ignored, then that network can be destroyed and the network
> definition file edited to correct the problem.

This explanation is fine for this patch, but I'd still (separately) like
a more detailed description of what makes the network unusable. Are we
missing something when we tear down the network if we fail at this
point? If so, we should fix our error exit code to do the right thing. I
think that can be done in a separate patch though,.


>   Unfortunately,
> the error message only appears in syslog.  However, with
> the checks performed when the network definition file is parsed,
> it is unlikely that this condition will ever occur.
>
> Handling of errors in this manner is consistent with other uses
> of the CommandRun interface.
>
> The command used is of the following form:
>
> ip route add <address>/<prefix> via <gateway> dev <virbr-bridge> \
> proto static metric 1
> .
> Signed-off-by: Gene Czarcinski <gene at czarc.net>
> ---
>  docs/formatnetwork.html.in                         |  80 +++++
>  docs/schemas/network.rng                           |  22 ++
>  src/conf/network_conf.c                            | 334 ++++++++++++++++++++-
>  src/conf/network_conf.h                            |  20 ++
>  src/libvirt_private.syms                           |   1 +
>  src/network/bridge_driver.c                        |  41 +++
>  src/util/virnetdev.c                               |  44 +++
>  src/util/virnetdev.h                               |   5 +
>  .../networkxml2xmlin/dhcp6host-routed-network.xml  |   2 +
>  .../networkxml2xmlout/dhcp6host-routed-network.xml |   2 +
>  10 files changed, 550 insertions(+), 1 deletion(-)
>
> diff --git a/docs/formatnetwork.html.in b/docs/formatnetwork.html.in
> index 4dd0415..cbf4a5c 100644
> --- a/docs/formatnetwork.html.in
> +++ b/docs/formatnetwork.html.in
> @@ -529,6 +529,60 @@
>        starting.
>      </p>
>  
> +    <h5><a name="elementsStaticroute">Static Routes</a></h5>
> +    <p>
> +      It has been possible to define static routes on a virtual bridge
> +      device <span class="since">Since 1.0.5</span>.  Static route


The documentation is meant to be a "snapshot of current behavior", not a
historical narrative (with annotations indicating when functionality was
introduced). Because of that, I think that "it has been possible to
define..." style isn't appropriate. We can just start of with "Static
route ....." and toss in a <since> at the end of the paragraph. That
will be more consistent with the rest of the document.



> +      definitions are used to provide routing information to the
> +      virtualization host for networks which are not defined as a
> +      network on one of the virtual bridges on the virtualization host.
> +    </p>
> +
> +    <p>
> +      As shown in <a href="formatnetwork.html#examplesNoGateway">this example</a>,
> +      it is possible to define a virtual bridge interface with no
> +      IPv4 or IPv6 networks.  Such interfaces are useful in supporting
> +      networks which have no visibility or direct connectivity with the
> +      virtualization host, but can be used to support
> +      virtual networks which only have guest connectivity.  A guest
> +      with connectivity to the guest-only network and another network
> +      that is directly reachable from the host can act as a gateway between the
> +      networks.  A static route added to the "visible" network definition
> +      provides the routing information so that IP packets can be sent
> +      from the virtualization host to guests on the hidden network.
> +    </p>


(This is all very good/useful information, but someday soon we need to
move it out of this "reference" type file into a "admin guide" type file.)


> +
> +    <p>
> +      Here is a fragment of a definition which shows the static
> +      route specification as well as the  IPv4 and IPv6 definitions
> +      for network addresses which are referred to in the
> +      <code>gateway</code> gateway address specifications.
> +    </p>
> +
> +    <pre>
> +      ...
> +        <ip address="192.168.122.1" netmask="255.255.255.0">
> +          <dhcp>
> +            <range start="192.168.122.128" end="192.168.122.254" />
> +          </dhcp>
> +        </ip>
> +        <route address="192.168.222.0" prefix="24" gateway="192.168.122.2" />
> +        <ip family="ipv6" address="2001:db8:ca2:2::1" prefix="64" />
> +        <route family="ipv6" address="2001:db8:ca2:3::" prefix="64" gateway="2001:db8:ca2:2::2">
> +        </route>
> +      ...
> +    </pre>
> +
> +    <p>
> +      Notice that the <code>route</code> elements look very similar to
> +      the <code>ip</code> address specification.  Although parts are the same,
> +      the meaning and effects of the two elements are very different.  The
> +      <code>ip</code> address specification results in an address being defined
> +      on the virtual bridge whereas the <code>route</code> definition is used
> +      to create the static route for the specified network via the gateway address
> +      on the virtual bridge device.
> +    </p>


This paragraph is unnecessary, and I think would just serve to confuse,
so it should be removed.


> +
>      <h3><a name="elementsAddress">Addressing</a></h3>
>  
>      <p>
> @@ -560,6 +614,7 @@
>            </dhcp>
>          </ip>
>          <ip family="ipv6" address="2001:db8:ca2:2::1" prefix="64" />
> +        <route family="ipv6" address="2001:db9:ca1:1::" prefix="64" gateway="2001:db8:ca2:2::2" />
>        </network></pre>
>  
>      <dl>
> @@ -809,6 +864,31 @@
>          </ip>
>        </network></pre>
>  
> +    <p>
> +      Below is yet another IPv6 variation.  This variation has only IPv6
> +      defined with DHCPv6 on the primary IPv6 network.  A static link
> +      if defined for a second IPv6 network which will not be visable on
> +      the bridge interface but rill have a static route defined for this

s/rill/will/


> +      network via the specified gateway. Note that the gateway address
> +      must be valid for the networks supported on the bridge interface.

"must be directly reachable via (on the same subnet as) one of the <ip>
addresses defined for this <network>"


> +      <span class="since">Since 1.0.5</span>
> +    </p>
> +
> +    <pre>
> +      <network>
> +        <name>net7</name>
> +        <bridge name="virbr7" />
> +        <forward mode="route"/>
> +        <ip family="ipv6" address="2001:db8:ca2:7::1" prefix="64" >
> +          <dhcp>
> +            <range start="2001:db8:ca2:7::100" end="2001:db8:ca2::1ff" />
> +            <host id="0:4:7e:7d:f0:7d:a8:bc:c5:d2:13:32:11:ed:16:ea:84:63" name="lucas" ip="2001:db8:ca2:2:3::4" />
> +          </dhcp>
> +        </ip>
> +        <route family="ipv6" address="2001:db8:ca2:8::" prefix="64" gateway="2001:db8:ca2:7::4" >
> +        </route>
> +      </network></pre>
> +
>      <h3><a name="examplesPrivate">Isolated network config</a></h3>
>  
>      <p>
> diff --git a/docs/schemas/network.rng b/docs/schemas/network.rng
> index 6c3fae2..5bcba32 100644
> --- a/docs/schemas/network.rng
> +++ b/docs/schemas/network.rng
> @@ -305,6 +305,28 @@
>              </optional>
>            </element>
>          </zeroOrMore>
> +        <!-- <route> element -->
> +        <zeroOrMore>
> +          <!-- The (static) route element specifies a network address and gateway
> +               address to access that network. -->
> +          <element name="route">
> +            <optional>
> +              <attribute name="family"><ref name="addr-family"/></attribute>
> +            </optional>
> +            <optional>
> +              <attribute name="address"><ref name="ipAddr"/></attribute>
> +            </optional>
> +            <optional>
> +              <choice>
> +                <attribute name="netmask"><ref name="ipv4Addr"/></attribute>
> +                <attribute name="prefix"><ref name="ipPrefix"/></attribute>
> +              </choice>
> +            </optional>
> +             <optional>
> +              <attribute name="gateway"><ref name="ipAddr"/></attribute>
> +            </optional>


<gateway> is mandatory. It doesn't make sense to have a route without a
gateway (w/o address or prefix is fine though - that makes it a default
route).


> +          </element>
> +        </zeroOrMore>
>        </interleave>
>      </element>
>    </define>
> diff --git a/src/conf/network_conf.c b/src/conf/network_conf.c
> index 1726066..2b56ca7 100644
> --- a/src/conf/network_conf.c
> +++ b/src/conf/network_conf.c
> @@ -137,6 +137,12 @@ virNetworkIpDefClear(virNetworkIpDefPtr def)
>  }
>  
>  static void
> +virNetworkRouteDefClear(virNetworkRouteDefPtr def)
> +{
> +    VIR_FREE(def->family);
> +}
> +
> +static void
>  virNetworkDNSTxtDefClear(virNetworkDNSTxtDefPtr def)
>  {
>      VIR_FREE(def->name);
> @@ -215,6 +221,11 @@ virNetworkDefFree(virNetworkDefPtr def)
>      }
>      VIR_FREE(def->ips);
>  
> +    for (ii = 0 ; ii < def->nroutes && def->routes ; ii++) {
> +        virNetworkRouteDefClear(&def->routes[ii]);
> +    }
> +    VIR_FREE(def->routes);
> +
>      for (ii = 0; ii < def->nPortGroups && def->portGroups; ii++) {
>          virPortGroupDefClear(&def->portGroups[ii]);
>      }
> @@ -1256,6 +1267,209 @@ cleanup:
>  }
>  
>  static int
> +virNetworkRouteDefParseXML(const char *networkName,
> +                           xmlNodePtr node,
> +                           xmlXPathContextPtr ctxt,
> +                           virNetworkRouteDefPtr def)
> +{
> +    /*
> +     * virNetworkRouteDef object is already allocated as part
> +     * of an array.  On failure clear: it out, but don't free it.
> +     */
> +
> +    xmlNodePtr save;
> +    char *address = NULL, *netmask = NULL;
> +    char *gateway = NULL;
> +    unsigned long prefix = 0;
> +    int result = -1;
> +    int prefixRc;
> +    virSocketAddr testAddr;
> +
> +    save = ctxt->node;
> +    ctxt->node = node;
> +
> +    /* grab raw data from XML */
> +    def->family = virXPathString("string(./@family)", ctxt);
> +
> +    address = virXPathString("string(./@address)", ctxt);
> +
> +    netmask = virXPathString("string(./@netmask)", ctxt);
> +
> +    gateway = virXPathString("string(./@gateway)", ctxt);
> +
> +    prefixRc = virXPathULong("string(./@prefix)", ctxt, &prefix);
> +    if (prefixRc == -2) {
> +        virReportError(VIR_ERR_XML_ERROR,
> +                       _("Invalid prefix specified in route definition '%s'"),
> +                       networkName);
> +        goto cleanup;
> +    }
> +
> +    /* Note: both network and gateway addresses must be specified */


address should be optional unless prefix or netmask is non-0, although
I've now noticed that won't be handled properly due to
virSocketAddrGetIpPrefix returning -1 when there is no address or prefix
or netmask (I'm fixing that before I push that patch, so you can just
toss your 1/2 patch, rebase, and assume it's fixed).


> +
> +    if (address) {
> +        if (virSocketAddrParse(&def->address, address, AF_UNSPEC) < 0) {
> +            virReportError(VIR_ERR_XML_ERROR,
> +                           _("Bad network address '%s' in route definition '%s'"),
> +                           address, networkName);
> +            goto cleanup;
> +        }
> +
> +    } else {
> +        virReportError(VIR_ERR_XML_ERROR,
> +                       _("A network address must be specified in route definition '%s'"),
> +                       networkName);
> +        goto cleanup;
> +    }
> +
> +    if (gateway) {
> +        if (virSocketAddrParse(&def->gateway, gateway, AF_UNSPEC) < 0) {
> +            virReportError(VIR_ERR_XML_ERROR,
> +                           _("Bad gateway address '%s' in route definition '%s'"),
> +                           gateway, networkName);
> +            goto cleanup;
> +        }
> +
> +    } else {
> +        virReportError(VIR_ERR_XML_ERROR,
> +                       _("A gateway address must be specified in route definition '%s'"),
> +                       networkName);
> +        goto cleanup;
> +    }

How about structuring it like this:


     if (!gateway) {
        "Missing error"
        goto cleanup;
     }
     if (virSocketAddrPars(...) < 0) {
        "bad gateway error"
        goto cleanup;
     }



> +
> +    /* validate network address, etc. for each family */
> +    if ((def->family == NULL) || (STREQ(def->family, "ipv4"))) {
> +        if (!(VIR_SOCKET_ADDR_IS_FAMILY(&def->address, AF_INET) ||
> +              VIR_SOCKET_ADDR_IS_FAMILY(&def->address, AF_UNSPEC))) {
> +            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> +                           _("%s family specified for non-IPv4 address '%s' in route definition '%s'"),
> +                           def->family == NULL? "no" : "ipv4", address, networkName);
> +            goto cleanup;
> +        }
> +        if (!(VIR_SOCKET_ADDR_IS_FAMILY(&def->gateway, AF_INET) ||
> +              VIR_SOCKET_ADDR_IS_FAMILY(&def->gateway, AF_UNSPEC))) {

gateway is required, so AF_UNSPEC is also unacceptable.


> +            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> +                           _("%s family specified for non-IPv4 gateway address '%s' in route definition '%s'"),
> +                           def->family == NULL? "no" : "ipv4", address, networkName);
> +            goto cleanup;
> +        }
> +        if (netmask) {
> +            if (virSocketAddrParse(&def->netmask, netmask, AF_UNSPEC) < 0) {
> +                virReportError(VIR_ERR_XML_ERROR,
> +                               _("Bad netmask address '%s' in route definition '%s'"),
> +                               netmask, networkName);
> +                goto cleanup;
> +            }


I think you're going to end up needing the parsed netmask sooner (when
you're trying to decide whether or not address is required), so you
should probably do this parsing right after you get the netmask string
from the xml.


> +
> +            if (!VIR_SOCKET_ADDR_IS_FAMILY(&def->netmask, AF_INET)) {
> +                virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> +                               _("network '%s' has invalid netmask '%s' for address '%s' (both must be IPv4)"),
> +                               networkName, netmask, address);
> +                goto cleanup;
> +            }
> +            if (!(prefixRc < 0)) {
> +                /* can't have both netmask and prefix at the same time */
> +                virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> +                               _("route definition '%s' cannot have both a prefix and a netmask"),
> +                               networkName);
> +                goto cleanup;
> +            }
> +        }
> +        else {

       } else {

> +            if (prefixRc < 0 || prefix == 0) {
> +                int num = virSocketAddrGetIpPrefix(&def->address, &def->netmask, prefix);
> +                if (num < 0) {
> +                    virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> +                                   _("Invalid IPv4 prefix specified in route definition '%s'"),
> +                                   networkName);
> +                    goto cleanup;
> +                }
> +                else
> +                    def->prefix = num;


You should only set def->prefix if the definition contains "prefix", not
if you're deriving it from netmask, or getting the natural netmask based
on network class. It will be useful to know the result of
virSocketAddrGetIpPrefix during the parse, but only in order to decide
whether or not "address" is optional; don't save it in the def.

> +            }
> +            else
> +                def->prefix = prefix;
> +        }
> +        if (prefix > 32 ) {


Extra space after "32" (make syntax-check catches this)


> +            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> +                           _("Invalid IPv4 prefix '%lu' for '%s' specified in route definition '%s'"),
> +                           prefix, def->family == NULL? "no" : "ipv4", networkName);
> +            goto cleanup;
> +        }
> +    } else if (STREQ(def->family, "ipv6")) {
> +        if (!VIR_SOCKET_ADDR_IS_FAMILY(&def->address, AF_INET6)) {
> +            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> +                           _("ipv6 family specified for non-IPv6 address '%s' in route definition '%s'"),
> +                           address, networkName);
> +            goto cleanup;
> +        }


address should be optional if prefix is 0.


> +        if (netmask) {
> +            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> +                           _("specifying netmask invalid for IPv6 address '%s' in route definition '%s'"),
> +                           address, networkName);
> +            goto cleanup;
> +        }
> +        if (!VIR_SOCKET_ADDR_IS_FAMILY(&def->gateway, AF_INET6)) {
> +            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> +                           _("ipv6 specified for non-IPv6 gateway address '%s' in route definition '%s'"),
> +                           gateway, networkName);
> +            goto cleanup;
> +        }
> +        if (prefix > 128 ) {

Another extra space.


> +            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> +                           _("Invalid IPv6 prefix '%lu' for '%s' specified in route definition '%s'"),
> +                           prefix, def->family, networkName);
> +            goto cleanup;
> +        }
> +        if (prefixRc < 0 || prefix == 0)
> +            def->prefix = 64;    /* IPv6 default */
> +        else
> +            def->prefix = prefix;


Again, you should only set def->prefix if the incoming xml has a prefix
attribute; don't automatically set it (only do that when you're creating
the commandline to add the route)


> +    } else {
> +        virReportError(VIR_ERR_XML_ERROR,
> +                       _("Unrecognized family '%s' in definition of route definition '%s'"),
> +                       def->family, networkName);
> +        goto cleanup;
> +    }
> +
> +    /* make sure the address is a network address */
> +    if (netmask) {
> +        if (virSocketAddrMask(&def->address, &def->netmask, &testAddr) < 0) {
> +            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> +                           _("error converting address '%s' with netmask '%s' to network-address in route definition '%s'"),
> +                           address, netmask, networkName);
> +            goto cleanup;
> +        }
> +    } else {
> +        if (virSocketAddrMaskByPrefix(&def->address, def->prefix, &testAddr) < 0) {
> +            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> +                           _("error converting address '%s' with prefix=%u to network-address in route definition '%s'"),
> +                           address, def->prefix, networkName);
> +            goto cleanup;
> +        }
> +    }
> +    if (!virSocketAddrEqual(&def->address, &testAddr)) {
> +        virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> +                       _("address '%s' is not a network-address in route definition '%s'"),


         "address '%s' in <route> definition of network '%s' is not a
network address"


> +                       address, networkName);
> +        goto cleanup;
> +    }
> +
> +    result = 0;
> +
> +cleanup:
> +    if (result < 0) {
> +        virNetworkRouteDefClear(def);
> +    }
> +    VIR_FREE(address);
> +    VIR_FREE(netmask);
> +    VIR_FREE(gateway);
> +
> +    ctxt->node = save;
> +    return result;
> +}
> +
> +static int
>  virNetworkPortGroupParseXML(virPortGroupDefPtr def,
>                              xmlNodePtr node,
>                              xmlXPathContextPtr ctxt)
> @@ -1652,8 +1866,9 @@ virNetworkDefParseXML(xmlXPathContextPtr ctxt)
>      char *tmp;
>      char *stp = NULL;
>      xmlNodePtr *ipNodes = NULL;
> +    xmlNodePtr *routeNodes = NULL;
>      xmlNodePtr *portGroupNodes = NULL;
> -    int nIps, nPortGroups;
> +    int nIps, nPortGroups, nRoutes;
>      xmlNodePtr dnsNode = NULL;
>      xmlNodePtr virtPortNode = NULL;
>      xmlNodePtr forwardNode = NULL;
> @@ -1807,6 +2022,76 @@ virNetworkDefParseXML(xmlXPathContextPtr ctxt)
>      }
>      VIR_FREE(ipNodes);
>  
> +    nRoutes = virXPathNodeSet("./route", ctxt, &routeNodes);
> +    if (nRoutes < 0)
> +        goto error;
> +
> +    if (nRoutes > 0) {
> +        int ii;
> +
> +        /* allocate array to hold all the route definitions */
> +        if (VIR_ALLOC_N(def->routes, nRoutes) < 0) {
> +            virReportOOMError();
> +            goto error;
> +        }
> +        /* parse each definition */
> +        for (ii = 0; ii < nRoutes; ii++) {
> +            int ret = virNetworkRouteDefParseXML(def->name, routeNodes[ii],
> +                                              ctxt, &def->routes[ii]);
> +            if (ret < 0)
> +                goto error;
> +            def->nroutes++;
> +        }
> +
> +        /* now validate the correctness of any static route gateways specified
> +         *
> +         * note: the parameters within each definition are varified/assumed valid;
> +         * the question being asked and answered here is if the specified gateway
> +         * address has a network definition (reachable) on this bridge.


   "if the specified gateway is directly reachable from this bridge"


> +         */
> +        nRoutes = def->nroutes;
> +        nIps = def->nips;
> +        for (ii = 0; ii < nRoutes; ii++) {
> +            int jj;
> +            virSocketAddr testAddr, testGw;
> +            bool addrMatch;
> +            virNetworkRouteDefPtr gwdef = &def->routes[ii];
> +            if (VIR_SOCKET_ADDR_VALID(&gwdef->gateway)) {
> +                addrMatch = false;
> +                for (jj = 0; jj < nIps; jj++) {
> +                    virNetworkIpDefPtr def2 = &def->ips[jj];
> +                    if ((VIR_SOCKET_ADDR_IS_FAMILY(&gwdef->gateway, AF_INET6)) &&
> +                        (!VIR_SOCKET_ADDR_IS_FAMILY(&def2->address, AF_INET6)))
> +                        continue;
> +                    if ((VIR_SOCKET_ADDR_IS_FAMILY(&def2->address, AF_INET6)) &&
> +                        (!VIR_SOCKET_ADDR_IS_FAMILY(&gwdef->gateway, AF_INET6)))
> +                        continue;
> +                    if ((VIR_SOCKET_ADDR_IS_FAMILY(&gwdef->gateway, AF_INET)) &&
> +                         VIR_SOCKET_ADDR_IS_FAMILY(&def2->address, AF_INET6))
> +                        continue;

Don't you just mean:

                       if (VIR_SOCKET_ADDR_FAMILY(&gwdef->gateway)
                           != VIR_SOCKET_ADDR_FAMILY(&def2->address)) {
                           continue;
                       }


> +                    int prefix = virNetworkIpDefPrefix(def2);
> +                    virSocketAddrMaskByPrefix(&def2->address, prefix, &testAddr);
> +                    virSocketAddrMaskByPrefix(&gwdef->gateway, prefix, &testGw);
> +                    if (VIR_SOCKET_ADDR_VALID(&testAddr) &&
> +                        VIR_SOCKET_ADDR_VALID(&testGw) &&
> +                        virSocketAddrEqual(&testAddr, &testGw)) {
> +                        addrMatch = true;
> +                        break;
> +                    }
> +                }
> +                if (!addrMatch) {
> +                    char *gw = virSocketAddrFormat(&gwdef->gateway);
> +                    virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> +                                   _("unreachable static route gateway '%s' specified for network '%s'"),
> +                                   gw, def->name);
> +                    VIR_FREE(gw);
> +                    goto error;
> +                }
> +            }
> +        }
> +    }
> +    VIR_FREE(routeNodes);


This VIR_FREE() needs to go down to the end of the function so that it's
always called, even on error returns.


> +
>      forwardNode = virXPathNode("./forward", ctxt);
>      if (forwardNode &&
>          virNetworkForwardDefParseXML(def->name, forwardNode, ctxt, &def->forward) < 0) {
> @@ -2179,6 +2464,48 @@ error:
>  }
>  
>  static int
> +virNetworkRouteDefFormat(virBufferPtr buf,
> +                      const virNetworkRouteDefPtr def)
> +{
> +    int result = -1;
> +
> +    virBufferAddLit(buf, "<route");
> +
> +    if (def->family) {
> +        virBufferAsprintf(buf, " family='%s'", def->family);
> +    }
> +    if (VIR_SOCKET_ADDR_VALID(&def->address)) {
> +        char *addr = virSocketAddrFormat(&def->address);
> +        if (!addr)
> +            goto error;
> +        virBufferAsprintf(buf, " address='%s'", addr);
> +        VIR_FREE(addr);
> +    }
> +    if (VIR_SOCKET_ADDR_VALID(&def->netmask)) {
> +        char *addr = virSocketAddrFormat(&def->netmask);
> +        if (!addr)
> +            goto error;
> +        virBufferAsprintf(buf, " netmask='%s'", addr);
> +        VIR_FREE(addr);
> +    }
> +    if (def->prefix > 0) {
> +        virBufferAsprintf(buf," prefix='%u'", def->prefix);
> +    }
> +    if (VIR_SOCKET_ADDR_VALID(&def->gateway)) {
> +        char *addr = virSocketAddrFormat(&def->gateway);
> +        if (!addr)
> +            goto error;
> +        virBufferAsprintf(buf, " gateway='%s'", addr);
> +        VIR_FREE(addr);
> +    }
> +    virBufferAddLit(buf, " />\n");


Remove the extra space before the "/" (don't forget to update the test
cases accordingly)


> +
> +    result = 0;
> +error:
> +    return result;
> +}
> +
> +static int
>  virPortGroupDefFormat(virBufferPtr buf,
>                        const virPortGroupDefPtr def)
>  {
> @@ -2376,6 +2703,11 @@ virNetworkDefFormatInternal(virBufferPtr buf,
>              goto error;
>      }
>  
> +    for (ii = 0; ii < def->nroutes; ii++) {
> +        if (virNetworkRouteDefFormat(buf, &def->routes[ii]) < 0)
> +            goto error;
> +    }
> +
>      if (virNetDevVPortProfileFormat(def->virtPortProfile, buf) < 0)
>          goto error;
>  
> diff --git a/src/conf/network_conf.h b/src/conf/network_conf.h
> index 6ce9a00..37e7858 100644
> --- a/src/conf/network_conf.h
> +++ b/src/conf/network_conf.h
> @@ -135,6 +135,23 @@ struct _virNetworkIpDef {
>      virSocketAddr bootserver;
>     };
>  
> +typedef struct _virNetworkRouteDef virNetworkRouteDef;
> +typedef virNetworkRouteDef *virNetworkRouteDefPtr;
> +struct _virNetworkRouteDef {
> +    char *family;               /* ipv4 or ipv6 - default is ipv4 */
> +    virSocketAddr address;      /* Routed Network IP address */
> +
> +    /* One or the other of the following two will be used for a given
> +     * Network address, but never both. The parser guarantees this.
> +     * The virSocketAddrGetIpPrefix() can be used to get a
> +     * valid prefix.
> +     */
> +    unsigned int prefix;        /* ipv6 - only prefix allowed */
> +    virSocketAddr netmask;      /* ipv4 - either netmask or prefix specified */
> +
> +    virSocketAddr gateway;      /* gateway IP address for ip-route */
> +   };
> +
>  typedef struct _virNetworkForwardIfDef virNetworkForwardIfDef;
>  typedef virNetworkForwardIfDef *virNetworkForwardIfDefPtr;
>  struct _virNetworkForwardIfDef {
> @@ -209,6 +226,9 @@ struct _virNetworkDef {
>      size_t nips;
>      virNetworkIpDefPtr ips; /* ptr to array of IP addresses on this network */
>  
> +    size_t nroutes;
> +    virNetworkRouteDefPtr routes; /* ptr to array of static routes on this interface */
> +
>      virNetworkDNSDef dns;   /* dns related configuration */
>      virNetDevVPortProfilePtr virtPortProfile;
>  
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index ade4525..987fe64 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -1466,6 +1466,7 @@ virNetDevReplaceMacAddress;
>  virNetDevReplaceNetConfig;
>  virNetDevRestoreMacAddress;
>  virNetDevRestoreNetConfig;
> +virNetDevSetGateway;
>  virNetDevSetIPv4Address;
>  virNetDevSetMAC;
>  virNetDevSetMTU;
> diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c
> index e8b314a..39f97d1 100644
> --- a/src/network/bridge_driver.c
> +++ b/src/network/bridge_driver.c
> @@ -2360,6 +2360,7 @@ out:
>      return ret;
>  }
>  
> +/* add an IP address to a bridge */
>  static int
>  networkAddAddrToBridge(virNetworkObjPtr network,
>                         virNetworkIpDefPtr ipdef)
> @@ -2380,6 +2381,30 @@ networkAddAddrToBridge(virNetworkObjPtr network,
>      return 0;
>  }
>  
> +/* add an IP (static) route to a bridge */
> +static int
> +networkAddRouteToBridge(virNetworkObjPtr network,
> +                        virNetworkRouteDefPtr routedef)
> +{
> +    int prefix = virSocketAddrGetIpPrefix(&routedef->address,
> +                                          &routedef->netmask,
> +                                          routedef->prefix);
> +
> +    if (prefix < 0) {
> +        virReportError(VIR_ERR_INTERNAL_ERROR,
> +                       _("bridge '%s' has an invalid netmask or IP address for route definition"),
> +                       network->def->bridge);
> +        return -1;
> +    }
> +
> +    if (virNetDevSetGateway(network->def->bridge,
> +                            &routedef->address,
> +                            prefix,
> +                            &routedef->gateway) < 0)
> +        return -1;
> +    return 0;
> +}
> +
>  static int
>  networkStartNetworkVirtual(struct network_driver *driver,
>                            virNetworkObjPtr network)
> @@ -2388,6 +2413,7 @@ networkStartNetworkVirtual(struct network_driver *driver,
>      bool v4present = false, v6present = false;
>      virErrorPtr save_err = NULL;
>      virNetworkIpDefPtr ipdef;
> +    virNetworkRouteDefPtr routedef;
>      char *macTapIfName = NULL;
>      int tapfd = -1;
>  
> @@ -2446,6 +2472,7 @@ networkStartNetworkVirtual(struct network_driver *driver,
>      if (networkAddIptablesRules(driver, network) < 0)
>          goto err1;
>  
> +    /* first, do all of the real addresses */

That comment just confuses - what is "real address"? (this is probably
an artifact of earlier versions of the patch where you re-used <ip> for
routes).


>      for (ii = 0;
>           (ipdef = virNetworkDefGetIpByIndex(network->def, AF_UNSPEC, ii));
>           ii++) {
> @@ -2464,6 +2491,20 @@ networkStartNetworkVirtual(struct network_driver *driver,
>      if (virNetDevSetOnline(network->def->bridge, 1) < 0)
>          goto err2;
>  
> +    /* now, do all of the static routes */


Now that routes have their own list, that comment is redundant as well
(the code self-documents)



> +    for (ii = 0; ii < network->def->nroutes; ii++) {
> +        routedef = &network->def->routes[ii];
> +        /* Add the IP route to the bridge */
> +        /* ignore errors, error msg will be generated */
> +        /* but libvirt will not know and net-destroy will work. */
> +        if (VIR_SOCKET_ADDR_VALID(&routedef->gateway)) {
> +            if (networkAddRouteToBridge(network, routedef) < 0) {
> +                /* an error occurred adding the static route */
> +                continue; /* for now, do nothing */
> +            }
> +        }
> +    }
> +
>      /* If forward.type != NONE, turn on global IP forwarding */
>      if (network->def->forward.type != VIR_NETWORK_FORWARD_NONE &&
>          networkEnableIpForwarding(v4present, v6present) < 0) {
> diff --git a/src/util/virnetdev.c b/src/util/virnetdev.c
> index 00e0f94..e4b5358 100644
> --- a/src/util/virnetdev.c
> +++ b/src/util/virnetdev.c
> @@ -769,6 +769,50 @@ cleanup:
>  }
>  
>  /**
> + * virNetDevSetGateway:
> + * @ifname: the interface name
> + * @addr: the IP network address (IPv4 or IPv6)
> + * @prefix: number of 1 bits in the netmask
> + * @gateway: via address for route (same as @addr)
> + *
> + * Add a route for a network IP address to an interface. This function
> + * *does not* remove any previously added IP static routes.
> + *
> + * Returns 0 in case of success or -1 in case of error.
> + */
> +
> +int virNetDevSetGateway(const char *ifname,
> +                        virSocketAddrPtr addr,
> +                        unsigned int prefix,
> +                        virSocketAddrPtr gateway)
> +{
> +    virCommandPtr cmd = NULL;
> +    char *addrstr = NULL, *gatewaystr = NULL;
> +    int ret = -1;
> +
> +    if (!(addrstr = virSocketAddrFormat(addr)))
> +        goto cleanup;
> +    if (!(gatewaystr = virSocketAddrFormat(gateway)))
> +        goto cleanup;
> +    cmd = virCommandNew(IP_PATH);
> +    virCommandAddArgList(cmd, "route", "add", NULL);
> +    virCommandAddArgFormat(cmd, "%s/%u", addrstr, prefix);
> +    virCommandAddArgList(cmd, "via", gatewaystr, "dev", ifname,
> +                              "proto", "static", "metric", NULL);
> +    virCommandAddArgFormat(cmd, "%u", 1);
> +
> +    if (virCommandRun(cmd, NULL) < 0)
> +        goto cleanup;
> +
> +    ret = 0;
> +cleanup:
> +    VIR_FREE(addrstr);
> +    VIR_FREE(gatewaystr);
> +    virCommandFree(cmd);
> +    return ret;
> +}
> +
> +/**
>   * virNetDevClearIPv4Address:
>   * @ifname: the interface name
>   * @addr: the IP address (IPv4 or IPv6)
> diff --git a/src/util/virnetdev.h b/src/util/virnetdev.h
> index 06d0650..07e2e63 100644
> --- a/src/util/virnetdev.h
> +++ b/src/util/virnetdev.h
> @@ -42,6 +42,11 @@ int virNetDevSetIPv4Address(const char *ifname,
>                              virSocketAddr *addr,
>                              unsigned int prefix)
>      ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
> +int virNetDevSetGateway(const char *ifname,
> +                        virSocketAddrPtr addr,
> +                        unsigned int prefix,
> +                        virSocketAddrPtr gateway)
> +    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(4) ATTRIBUTE_RETURN_CHECK;
>  int virNetDevClearIPv4Address(const char *ifname,
>                                virSocketAddr *addr,
>                                unsigned int prefix)
> diff --git a/tests/networkxml2xmlin/dhcp6host-routed-network.xml b/tests/networkxml2xmlin/dhcp6host-routed-network.xml
> index 2693d87..991ce19 100644
> --- a/tests/networkxml2xmlin/dhcp6host-routed-network.xml
> +++ b/tests/networkxml2xmlin/dhcp6host-routed-network.xml
> @@ -19,4 +19,6 @@
>        <host id='0:1:0:1:18:aa:62:fe:0:16:3e:44:55:66' name='badbob' ip='2001:db8:ac10:fd01::1:24' />
>      </dhcp>
>    </ip>
> +  <route address="192.168.222.0" netmask="255.255.255.0" gateway="192.168.122.10" />
> +  <route family="ipv6" address="2001:db8:ac10:fc00::" prefix="64" gateway="2001:db8:ac10:fd01::1:24" />
>  </network>
> diff --git a/tests/networkxml2xmlout/dhcp6host-routed-network.xml b/tests/networkxml2xmlout/dhcp6host-routed-network.xml
> index 7305043..90a0e0a 100644
> --- a/tests/networkxml2xmlout/dhcp6host-routed-network.xml
> +++ b/tests/networkxml2xmlout/dhcp6host-routed-network.xml
> @@ -21,4 +21,6 @@
>        <host id='0:1:0:1:18:aa:62:fe:0:16:3e:44:55:66' name='badbob' ip='2001:db8:ac10:fd01::1:24' />
>      </dhcp>
>    </ip>
> +  <route address='192.168.222.0' netmask='255.255.255.0' gateway='192.168.122.10' />
> +  <route family='ipv6' address='2001:db8:ac10:fc00::' prefix='64' gateway='2001:db8:ac10:fd01::1:24' />
>  </network>


This is *very* close!




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