From: Daniel P. Berrangé <berrange@redhat.com>
Date: Mon, 8 Jun 2020 13:35:02 +0000 (+0100)
Subject: conf: add an attribute to turn on NAT for IPv6 virtual networks
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=927acaedec7effbe67a154d8bfa0e67f7d08e6c7;p=libvirt.git

conf: add an attribute to turn on NAT for IPv6 virtual networks

Historically IPv6 did not support NAT, so when IPv6 was added to
libvirt's virtual networks, when requesting <forward mode="nat"/>
libvirt will NOT apply NAT to IPv6 traffic, only IPv4 traffic.

This is an annoying historical design decision as it means we
cannot enable IPv6 automatically. We thus need to introduce a
new attribute

   <forward mode="nat">
     <nat ipv6="yes"/>
   </forward>

Reviewed-by: Laine Stump <laine@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---

diff --git a/docs/formatnetwork.html.in b/docs/formatnetwork.html.in
index 0383e2d891..fb740111b1 100644
--- a/docs/formatnetwork.html.in
+++ b/docs/formatnetwork.html.in
@@ -276,6 +276,20 @@
     &lt;/nat&gt;
   &lt;/forward&gt;
 ...</pre>
+
+            <p>
+              <span class="since">Since 6.5.0</span> it is possible to
+              enable NAT with IPv6 networking. As noted above, IPv6
+              has historically done plain forwarding and thus to avoid
+              breaking historical compatibility, IPv6 NAT must be
+              explicitly requested.
+            </p>
+            <pre>
+...
+  &lt;forward mode='nat'&gt;
+    &lt;nat ipv6='yes'/&gt;
+  &lt;/forward&gt;
+...</pre>
           </dd>
 
           <dt><code>route</code></dt>
diff --git a/docs/schemas/network.rng b/docs/schemas/network.rng
index 88b6f4dfdd..3a5eb3ced4 100644
--- a/docs/schemas/network.rng
+++ b/docs/schemas/network.rng
@@ -181,6 +181,11 @@
               </optional>
               <optional>
                 <element name='nat'>
+                  <optional>
+                    <attribute name="ipv6">
+                      <ref name="virYesNo"/>
+                    </attribute>
+                  </optional>
                   <interleave>
                     <optional>
                       <element name='address'>
diff --git a/src/conf/network_conf.c b/src/conf/network_conf.c
index f1d22b25b1..caccc6b1b9 100644
--- a/src/conf/network_conf.c
+++ b/src/conf/network_conf.c
@@ -1358,6 +1358,7 @@ virNetworkForwardNatDefParseXML(const char *networkName,
     int nNatAddrs, nNatPorts;
     char *addrStart = NULL;
     char *addrEnd = NULL;
+    char *ipv6 = NULL;
     VIR_XPATH_NODE_AUTORESTORE(ctxt);
 
     ctxt->node = node;
@@ -1369,6 +1370,21 @@ virNetworkForwardNatDefParseXML(const char *networkName,
         goto cleanup;
     }
 
+    ipv6 = virXMLPropString(node, "ipv6");
+    if (ipv6) {
+        int natIPv6;
+        if ((natIPv6 = virTristateBoolTypeFromString(ipv6)) <= 0) {
+            virReportError(VIR_ERR_XML_ERROR,
+                           _("Invalid ipv6 setting '%s' "
+                             "in network '%s' NAT"),
+                           ipv6, networkName);
+            VIR_FREE(ipv6);
+            goto cleanup;
+        }
+        def->natIPv6 = natIPv6;
+        VIR_FREE(ipv6);
+    }
+
     /* addresses for SNAT */
     nNatAddrs = virXPathNodeSet("./address", ctxt, &natAddrNodes);
     if (nNatAddrs < 0) {
@@ -2516,10 +2532,18 @@ virNetworkForwardNatDefFormat(virBufferPtr buf,
             goto cleanup;
     }
 
-    if (!addrEnd && !addrStart && !fwd->port.start && !fwd->port.end)
+    if (!addrEnd && !addrStart && !fwd->port.start && !fwd->port.end && !fwd->natIPv6)
         return 0;
 
-    virBufferAddLit(buf, "<nat>\n");
+    virBufferAddLit(buf, "<nat");
+    if (fwd->natIPv6)
+        virBufferAsprintf(buf, " ipv6='%s'", virTristateBoolTypeToString(fwd->natIPv6));
+
+    if (!addrEnd && !addrStart && !fwd->port.start && !fwd->port.end) {
+        virBufferAddLit(buf, "/>\n");
+        return 0;
+    }
+    virBufferAddLit(buf, ">\n");
     virBufferAdjustIndent(buf, 2);
 
     if (addrStart) {
@@ -2627,7 +2651,8 @@ virNetworkDefFormatBuf(virBufferPtr buf,
                          || def->forward.port.start
                          || def->forward.port.end
                          || (def->forward.driverName
-                             != VIR_NETWORK_FORWARD_DRIVER_NAME_DEFAULT));
+                             != VIR_NETWORK_FORWARD_DRIVER_NAME_DEFAULT)
+                         || def->forward.natIPv6);
         virBufferAsprintf(buf, "%s>\n", shortforward ? "/" : "");
         virBufferAdjustIndent(buf, 2);
 
diff --git a/src/conf/network_conf.h b/src/conf/network_conf.h
index f2dc388ef0..e3a61c62ea 100644
--- a/src/conf/network_conf.h
+++ b/src/conf/network_conf.h
@@ -244,6 +244,8 @@ struct _virNetworkForwardDef {
     /* ranges for NAT */
     virSocketAddrRange addr;
     virPortRange port;
+
+    virTristateBool natIPv6;
 };
 
 typedef struct _virPortGroupDef virPortGroupDef;
diff --git a/tests/networkxml2xmlin/nat-network-forward-nat-ipv6.xml b/tests/networkxml2xmlin/nat-network-forward-nat-ipv6.xml
new file mode 100644
index 0000000000..c360941e1e
--- /dev/null
+++ b/tests/networkxml2xmlin/nat-network-forward-nat-ipv6.xml
@@ -0,0 +1,10 @@
+<network>
+  <name>default</name>
+  <uuid>81ff0d90-c91e-6742-64da-4a736edb9a9b</uuid>
+  <bridge name="virbr0"/>
+  <forward mode="nat">
+    <nat ipv6="yes"/>
+  </forward>
+  <ip family="ipv6" address="2001:db8:ac10:fe01::1" prefix="64">
+  </ip>
+</network>
diff --git a/tests/networkxml2xmlout/nat-network-forward-nat-ipv6.xml b/tests/networkxml2xmlout/nat-network-forward-nat-ipv6.xml
new file mode 100644
index 0000000000..cfec391ee2
--- /dev/null
+++ b/tests/networkxml2xmlout/nat-network-forward-nat-ipv6.xml
@@ -0,0 +1,10 @@
+<network>
+  <name>default</name>
+  <uuid>81ff0d90-c91e-6742-64da-4a736edb9a9b</uuid>
+  <forward mode='nat'>
+    <nat ipv6='yes'/>
+  </forward>
+  <bridge name='virbr0' stp='on' delay='0'/>
+  <ip family='ipv6' address='2001:db8:ac10:fe01::1' prefix='64'>
+  </ip>
+</network>
diff --git a/tests/networkxml2xmltest.c b/tests/networkxml2xmltest.c
index 700744785a..17817418b7 100644
--- a/tests/networkxml2xmltest.c
+++ b/tests/networkxml2xmltest.c
@@ -140,6 +140,7 @@ mymain(void)
     DO_TEST("nat-network-dns-forward-plain");
     DO_TEST("nat-network-dns-forwarders");
     DO_TEST("nat-network-dns-forwarder-no-resolv");
+    DO_TEST("nat-network-forward-nat-ipv6");
     DO_TEST("nat-network-forward-nat-address");
     DO_TEST("nat-network-forward-nat-no-address");
     DO_TEST("nat-network-mtu");