Implement requesting the name ip

Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)

container.go

@@ -1109,36 +1109,32 @@ func (container *Container) allocateNetwork() error {
 
 	var (
 		env *engine.Env
+		err error
 		eng = container.runtime.eng
 	)
+
 	if container.State.IsGhost() {
 		if container.runtime.config.DisableNetwork {
 			env = &engine.Env{}
 		} else {
-			// TODO: @crosbymichael
-			panic("not implemented")
-			/*
-				iface = &NetworkInterface{
-					IPNet:   net.IPNet{IP: net.ParseIP(container.NetworkSettings.IPAddress), Mask: manager.bridgeNetwork.Mask},
-					Gateway: manager.bridgeNetwork.IP,
-				}
+			currentIP := container.NetworkSettings.IPAddress
 
-				// request an existing ip
-				if iface != nil && iface.IPNet.IP != nil {
-					if _, err := ipallocator.RequestIP(manager.bridgeNetwork, &iface.IPNet.IP); err != nil {
-						return err
-					}
-				} else {
-					job = eng.Job("allocate_interface", container.ID)
-					if err := job.Run(); err != nil {
-						return err
-					}
-				}
-			*/
+			job := eng.Job("allocate_interface", container.ID)
+			if currentIP != "" {
+				job.Setenv("RequestIP", currentIP)
+			}
+
+			env, err = job.Stdout.AddEnv()
+			if err != nil {
+				return err
+			}
+
+			if err := job.Run(); err != nil {
+				return err
+			}
 		}
 	} else {
 		job := eng.Job("allocate_interface", container.ID)
-		var err error
 		env, err = job.Stdout.AddEnv()
 		if err != nil {
 			return err

networkdriver/lxc/driver.go

@@ -304,9 +304,18 @@ func createBridgeIface(name string) error {
 
 // Allocate a network interface
 func Allocate(job *engine.Job) engine.Status {
-	id := job.Args[0]
+	var (
+		ip          *net.IP
+		err         error
+		id          = job.Args[0]
+		requestedIP = net.ParseIP(job.Getenv("RequestedIP"))
+	)
 
-	ip, err := ipallocator.RequestIP(bridgeNetwork, nil)
+	if requestedIP != nil {
+		ip, err = ipallocator.RequestIP(bridgeNetwork, &requestedIP)
+	} else {
+		ip, err = ipallocator.RequestIP(bridgeNetwork, nil)
+	}
 	if err != nil {
 		job.Error(err)
 		return engine.StatusErr