drivers/macvlan: Add support for optional runtime hint

docker supports alternate OCI runtimes including virtual machine
based runtimes. In certian cases network plugins can optionally
choose to support creation of  virtual machine friendly interfaces
using optional network options.

This is illustrated here with the hint being used by the macvlan
driver to create a macvtap interface vs a macvlan interface when
the runtime is known to be a VM based runtime.

docker run --runtime=cor -it --net=pub_net --network "name=pub_net,runtime=namespace" alpine sh

This is currently based off of
moby/moby#27638

However this will be implemented as per the proposal
moby/moby#31964

Signed-off-by: Manohar Castelino <manohar.r.castelino@intel.com>

drivers/macvlan/macvlan.go

@@ -46,6 +46,7 @@ type endpoint struct {
 	srcName  string
 	dbIndex  uint64
 	dbExists bool
+	runtime  string
 }
 
 type network struct {

drivers/macvlan/macvlan_endpoint.go

@@ -40,6 +40,7 @@ func (d *driver) CreateEndpoint(nid, eid string, ifInfo driverapi.InterfaceInfo,
 			return err
 		}
 	}
+
 	// disallow portmapping -p
 	if opt, ok := epOptions[netlabel.PortMap]; ok {
 		if _, ok := opt.([]types.PortBinding); ok {
@@ -57,6 +58,18 @@ func (d *driver) CreateEndpoint(nid, eid string, ifInfo driverapi.InterfaceInfo,
 		}
 	}
 
+	// Setup the runtime to default to namespace, override if specified
+	ep.runtime = "namespace"
+	if opt, ok := epOptions["runtime"]; ok {
+		if runtime, ok := opt.(string); ok {
+			if runtime != "namespace" && runtime != "vm" {
+				logrus.Warnf("driver does not support [%s] runtime", runtime)
+			} else {
+				ep.runtime = runtime
+			}
+		}
+	}
+
 	if err := d.storeUpdate(ep); err != nil {
 		return fmt.Errorf("failed to save macvlan endpoint %s to store: %v", ep.id[0:7], err)
 	}

drivers/macvlan/macvlan_joinleave.go

@@ -28,7 +28,7 @@ func (d *driver) Join(nid, eid string, sboxKey string, jinfo driverapi.JoinInfo,
 		return fmt.Errorf("error generating an interface name: %s", err)
 	}
 	// create the netlink macvlan interface
-	vethName, err := createMacVlan(containerIfName, n.config.Parent, n.config.MacvlanMode)
+	vethName, err := createMacVlan(containerIfName, n.config.Parent, n.config.MacvlanMode, endpoint.runtime)
 	if err != nil {
 		return err
 	}

drivers/macvlan/macvlan_setup.go

@@ -16,8 +16,8 @@ const (
 	macvlanMajorVer  = 9     // minimum macvlan major kernel support
 )
 
-// Create the macvlan slave specifying the source name
-func createMacVlan(containerIfName, parent, macvlanMode string) (string, error) {
+// Create the macvlan slave specifying the source name and the runtime type
+func createMacVlan(containerIfName, parent, macvlanMode, runtime string) (string, error) {
 	// Set the macvlan mode. Default is bridge mode
 	mode, err := setMacVlanMode(macvlanMode)
 	if err != nil {
@@ -32,20 +32,40 @@ func createMacVlan(containerIfName, parent, macvlanMode string) (string, error)
 	if err != nil {
 		return "", fmt.Errorf("error occoured looking up the %s parent iface %s error: %s", macvlanType, parent, err)
 	}
-	// Create a macvlan link
-	macvlan := &netlink.Macvlan{
-		LinkAttrs: netlink.LinkAttrs{
-			Name:        containerIfName,
-			ParentIndex: parentLink.Attrs().Index,
-		},
-		Mode: mode,
-	}
-	if err := ns.NlHandle().LinkAdd(macvlan); err != nil {
-		// If a user creates a macvlan and ipvlan on same parent, only one slave iface can be active at a time.
-		return "", fmt.Errorf("failed to create the %s port: %v", macvlanType, err)
-	}
 
-	return macvlan.Attrs().Name, nil
+	if runtime == "vm" {
+		// Create a macvtap link
+		macvtap := &netlink.Macvtap{
+			Macvlan: netlink.Macvlan{
+				LinkAttrs: netlink.LinkAttrs{
+					Name:        containerIfName,
+					ParentIndex: parentLink.Attrs().Index,
+				},
+				Mode: mode,
+			},
+		}
+
+		if err := ns.NlHandle().LinkAdd(macvtap); err != nil {
+			return "", fmt.Errorf("failed to create the %s port: %v", macvlanType, err)
+		}
+
+		return macvtap.Attrs().Name, nil
+	} else {
+		// Create a macvlan link
+		macvlan := &netlink.Macvlan{
+			LinkAttrs: netlink.LinkAttrs{
+				Name:        containerIfName,
+				ParentIndex: parentLink.Attrs().Index,
+			},
+			Mode: mode,
+		}
+		if err := ns.NlHandle().LinkAdd(macvlan); err != nil {
+			// If a user creates a macvlan and ipvlan on same parent, only one slave iface can be active at a time.
+			return "", fmt.Errorf("failed to create the %s port: %v", macvlanType, err)
+		}
+
+		return macvlan.Attrs().Name, nil
+	}
 }
 
 // setMacVlanMode setter for one of the four macvlan port types

drivers/macvlan/macvlan_store.go

@@ -255,6 +255,7 @@ func (ep *endpoint) MarshalJSON() ([]byte, error) {
 	epMap["id"] = ep.id
 	epMap["nid"] = ep.nid
 	epMap["SrcName"] = ep.srcName
+	epMap["runtime"] = ep.runtime
 	if len(ep.mac) != 0 {
 		epMap["MacAddress"] = ep.mac.String()
 	}
@@ -295,6 +296,7 @@ func (ep *endpoint) UnmarshalJSON(b []byte) error {
 	ep.id = epMap["id"].(string)
 	ep.nid = epMap["nid"].(string)
 	ep.srcName = epMap["SrcName"].(string)
+	ep.runtime = epMap["runtime"].(string)
 
 	return nil
 }