datapath-windows: Clarify externalVport.

In this patch, we add some explanation about the usage of
'externalVport' in the switch context. Also, we rename 'externalVport'
to 'virtualExternalVport' in alignment with the explanation. Also, we
rename 'numVports' to 'numHvVports' since ports are added from 2 ends
now.

Signed-off-by: Nithin Raju <nithin@vmware.com>
Acked-by: Alin Gabriel Serdean <aserdean@cloudbasesolutions.com>
Tested-by: Alin Gabriel Serdean <aserdean@cloudbasesolutions.com>
Acked-by: Ankur Sharma <ankursharma@vmware.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>

1 files changed, 43 insertions, 9 deletions

diff --git a/datapath-windows/ovsext/Switch.h b/datapath-windows/ovsext/Switch.h
index b61462b43..11d9df623 100644
--- a/datapath-windows/ovsext/Switch.h
+++ b/datapath-windows/ovsext/Switch.h
@@ -95,26 +95,60 @@ typedef struct _OVS_SWITCH_CONTEXT
 
     UINT32                  dpNo;
 
-    NDIS_SWITCH_PORT_ID     externalPortId;
+    /*
+     * 'virtualExternalVport' represents default external interface. This is
+     * a virtual interface. The friendly name of such an interface has
+     * been observed to be: "Microsoft Default External Interface". This NIC
+     * has 'NicIndex' == 0.
+     *
+     * The "real" physical external NIC has 'NicIndex' > 0. For each
+     * external interface, virtual or physical, NDIS gives an NIC level
+     * OID callback. Note that, even though there are multile "NICs",
+     * there's only one underlying Hyper-V port. Thus, we get a single
+     * NDIS port-level callback, but multiple NDIS NIC-level callbacks.
+     *
+     * The virtual external NIC can be accessed at 'virtualExternalVport', and
+     * is assigned the name "external.defaultAdapter". The virtual external
+     * NIC is not inserted into the 'portIdHashArray' since the port must not
+     * be exposed to OVS userspace.
+     *
+     * The physical external NICs are assigned names "external.%INDEX%",
+     * where '%INDEX%' represents the 'NicIndex' of the NIC.
+     *
+     * While adding a physical external NIC in OvsInitConfiguredSwitchNics(),
+     * some required properties of the vport are available only at the
+     * NDIS port-level. So, these are copied from 'virtualExternalVport'.
+     * The vport created for the physical external NIC is inserted into the
+     * 'portIdHashArray'.
+     *
+     * When the virtual external NIC is torn down or deleted, the
+     * corresponding physical external ports are also torn down or
+     * deleted. The number of physical external NICs is tracked by
+     * 'numPhysicalNics'.
+     */
+    NDIS_SWITCH_PORT_ID     virtualExternalPortId;
     NDIS_SWITCH_PORT_ID     internalPortId;
-    POVS_VPORT_ENTRY        externalVport;  // the virtual adapter vport
+    POVS_VPORT_ENTRY        virtualExternalVport;   // the virtual adapter vport
     POVS_VPORT_ENTRY        internalVport;
 
-    /*
-     * XXX when we support multiple VXLAN ports, we will need a list entry
-     * instead
-     */
     POVS_VPORT_ENTRY        vxlanVport;
 
     PLIST_ENTRY             ovsPortNameHashArray;   // based on ovsName
-    PLIST_ENTRY             portIdHashArray;        // based on portId
+    PLIST_ENTRY             portIdHashArray;        // based on Hyper-V portId
     PLIST_ENTRY             portNoHashArray;        // based on ovs port number
     PLIST_ENTRY             pidHashArray;           // based on packet pids
     NDIS_SPIN_LOCK          pidHashLock;            // Lock for pidHash table
 
+    /*
+     * 'numPhysicalNics' is the number of physical external NICs.
+     * 'numHvVports' is the number of Hyper-V switch ports added to OVS
+     * via the NDIS callbacks.
+     * 'numNonHvVports' is the number of ports added from userspace that are
+     * not on the Hyper-V switch. Eg. tunnel ports.
+     */
     UINT32                  numPhysicalNics;
-    UINT32                  numVports;     // include validation port
-    UINT32                  lastPortIndex;
+    UINT32                  numHvVports;
+    UINT32                  numNonHvVports;
 
     /* Lock taken over the switch. This protects the ports on the switch. */
     PNDIS_RW_LOCK_EX        dispatchLock;