conf: support partially-specified <virtualport> in parser and formatter

Until now, all attributes in a <virtualport> parameter list that were
acceptable for a particular type, were also required. There were no
optional attributes.

One of the aims of supporting <virtualport> in libvirt's virtual
networks and portgroups is to allow specifying the group-wide
parameters in the network's virtualport, and merge that with the
interface's virtualport, which will have the instance-specific info
(i.e. the interfaceid or instanceid).

Additionally, the guest's interface XML shouldn't need to know what
type of network connection will be used prior to runtime - it could be
openvswitch, 802.1Qbh, 802.1Qbg, or none of the above - but should
still be able to specify instance-specific info just in case it turns
out to be applicable.

Finally, up to now, the parser for virtualport has always generated a
random instanceid/interfaceid when appropriate, making it impossible
to leave it blank (which is what's required for virtualports within a
network/portprofile definition).

This patch modifies the parser and formatter of the <virtualport>
element in the following ways:

* because most of the attributes in a virNetDevVPortProfile are fixed
  size binary data with no reserved values, there is no way to embed a
  "this value wasn't specified" sentinel into the existing data. To
  solve this problem, the new *_specified fields in the
  virNetDevVPortProfile object that were added in a previous patch of
  this series are now set when the corresponding attribute is present
  during the parse.

* allow parsing/formatting a <virtualport> that has no type set. In
  this case, all fields are settable, but all are also optional.

* add a GENERATE_MISSING_DEFAULTS flag to the parser - if this flag is
  set and an instanceid/interfaceid is expected but not provided, a
  random one will be generated. This was previously the default
  behavior, but is now done only for virtualports inside an
  <interface> definition, not for those in <network> or <portgroup>.

* add a REQUIRE_ALL_ATTRIBUTES flag to the parser - if this flag is
  set the parser will call the new
  virNetDevVPortProfileCheckComplete() functions at the end of the
  parser to check for any missing attributes (based on type), and
  return failure if anything is missing. This used to be default
  behavior. Now it is only used for the virtualport defined inside an
  interface's <actual> element (by the time you've figured out the
  contents of <actual>, you should have all the necessary data to fill
  in the entire virtualport)

* add a REQUIRE_TYPE flag to the parser - if this flag is set, the
  parser will return an error if the virtualport has no type
  attribute. This also was previously the default behavior, but isn't
  needed in the case of the virtualport for a type='network' interface
  (i.e. the exact type isn't yet known), or the virtualport of a
  portgroup (i.e. the portgroup just has modifiers for the network's
  virtualport, which *does* require a type) - in those cases, the
  check will be done at domain startup, once the final virtualport is
  assembled (this is handled in the next patch).

2 files changed, 19 insertions, 3 deletions

diff --git a/tests/networkxml2xmlin/openvswitch-net.xml b/tests/networkxml2xmlin/openvswitch-net.xml
new file mode 100644
index 000000000..8aa1897ab
--- /dev/null
+++ b/tests/networkxml2xmlin/openvswitch-net.xml
@@ -0,0 +1,16 @@
+<network>
+  <name>openvswitch-net</name>
+  <uuid>81ff0d90-c92e-6742-64da-4a736edb9a8b</uuid>
+  <forward mode='bridge'/>
+  <virtualport type='openvswitch'/>
+  <portgroup name='bob' default='yes'>
+    <virtualport>
+      <parameters profileid='bob-profile'/>
+    </virtualport>
+  </portgroup>
+  <portgroup name='alice'>
+    <virtualport>
+      <parameters profileid='alice-profile'/>
+    </virtualport>
+  </portgroup>
+</network>
diff --git a/tests/networkxml2xmlin/vepa-net.xml b/tests/networkxml2xmlin/vepa-net.xml
index b1a40c6e5..030c1d162 100644
--- a/tests/networkxml2xmlin/vepa-net.xml
+++ b/tests/networkxml2xmlin/vepa-net.xml
@@ -7,16 +7,16 @@
     <interface dev="eth3"/>
   </forward>
   <virtualport type="802.1Qbg">
-    <parameters managerid="11" typeid="1193047" typeidversion="2" instanceid="b153fa89-1b87-9719-ec12-99e0054fb844"/>
+    <parameters managerid="11" typeid="1193047" typeidversion="2"/>
   </virtualport>
   <portgroup name="bob" default="yes">
     <virtualport type="802.1Qbg">
-      <parameters managerid="12" typeid="2193047" typeidversion="3" instanceid="5d00e0ba-e15c-959c-fbb6-b595b0655735"/>
+      <parameters typeid="2193047" typeidversion="3"/>
     </virtualport>
   </portgroup>
   <portgroup name="alice">
     <virtualport type="802.1Qbg">
-      <parameters managerid="13" typeid="3193047" typeidversion="4" instanceid="70bf45f9-01a8-f5ee-3c0f-e25a0a2e44a6"/>
+      <parameters managerid="13"/>
     </virtualport>
   </portgroup>
 </network>