@@ -37,24 +37,16 @@ func SetIptablesChain(c *iptables.Chain) {

 	chain = c

 }

-func Map(container net.Addr, hostIP net.IP, hostPort int) (net.Addr, error) {

+func Map(container net.Addr, hostIP net.IP, hostPort int) (host net.Addr, err error) {

 	lock.Lock()

 	defer lock.Unlock()

 	var (

 		m                 *mapping

-		err               error

 		proto             string

 		allocatedHostPort int

 	)

-	// release the port on any error during return.

-	defer func() {

-		if err != nil {

-			portallocator.ReleasePort(hostIP, proto, allocatedHostPort)

-		}

-	}()

-

 	switch container.(type) {

 	case *net.TCPAddr:

 		proto = "tcp"

@@ -77,14 +69,19 @@ func Map(container net.Addr, hostIP net.IP, hostPort int) (net.Addr, error) {

 			container: container,

 		}

 	default:

-		err = ErrUnknownBackendAddressType

-		return nil, err

+		return nil, ErrUnknownBackendAddressType

 	}

+	// release the allocated port on any further error during return.

+	defer func() {

+		if err != nil {

+			portallocator.ReleasePort(hostIP, proto, allocatedHostPort)

+		}

+	}()

+

 	key := getKey(m.host)

 	if _, exists := currentMappings[key]; exists {

-		err = ErrPortMappedForIP

-		return nil, err

+		return nil, ErrPortMappedForIP

 	}

 	containerIP, containerPort := getIPAndPort(m.container)