@@ -455,12 +455,25 @@ func initBridgeDriver(controller libnetwork.NetworkController, config *Config) e

 		ipamV4Conf.AuxAddresses["DefaultGatewayIPv4"] = config.Bridge.DefaultGatewayIPv4.String()

 	}

-	var ipamV6Conf *libnetwork.IpamConf

+	var (

+		ipamV6Conf     *libnetwork.IpamConf

+		deferIPv6Alloc bool

+	)

 	if config.Bridge.FixedCIDRv6 != "" {

 		_, fCIDRv6, err := net.ParseCIDR(config.Bridge.FixedCIDRv6)

 		if err != nil {

 			return err

 		}

+

+		// In case user has specified the daemon flag --fixed-cidr-v6 and the passed network has

+		// at least 48 host bits, we need to guarantee the current behavior where the containers'

+		// IPv6 addresses will be constructed based on the containers' interface MAC address.

+		// We do so by telling libnetwork to defer the IPv6 address allocation for the endpoints

+		// on this network until after the driver has created the endpoint and returned the

+		// constructed address. Libnetwork will then reserve this address with the ipam driver.

+		ones, _ := fCIDRv6.Mask.Size()

+		deferIPv6Alloc = ones <= 80

+

 		if ipamV6Conf == nil {

 			ipamV6Conf = &libnetwork.IpamConf{}

 		}

@@ -485,7 +498,8 @@ func initBridgeDriver(controller libnetwork.NetworkController, config *Config) e

 			netlabel.GenericData: netOption,

 			netlabel.EnableIPv6:  config.Bridge.EnableIPv6,

 		}),

-		libnetwork.NetworkOptionIpam("default", "", v4Conf, v6Conf))

+		libnetwork.NetworkOptionIpam("default", "", v4Conf, v6Conf),

+		libnetwork.NetworkOptionDeferIPv6Alloc(deferIPv6Alloc))

 	if err != nil {

 		return fmt.Errorf("Error creating default \"bridge\" network: %v", err)

 	}

@@ -377,6 +377,29 @@ func (s *DockerSuite) TestDaemonIPv6FixedCIDR(c *check.C) {

 	}

 }

+// TestDaemonIPv6FixedCIDRAndMac checks that when the daemon is started with ipv6 fixed CIDR

+// the running containers are given a an IPv6 address derived from the MAC address and the ipv6 fixed CIDR

+func (s *DockerSuite) TestDaemonIPv6FixedCIDRAndMac(c *check.C) {

+	err := setupV6()

+	c.Assert(err, checker.IsNil)

+

+	d := NewDaemon(c)

+

+	err = d.StartWithBusybox("--ipv6", "--fixed-cidr-v6='2001:db8:1::/64'")

+	c.Assert(err, checker.IsNil)

+	defer d.Stop()

+

+	out, err := d.Cmd("run", "-itd", "--name=ipv6test", "--mac-address", "AA:BB:CC:DD:EE:FF", "busybox")

+	c.Assert(err, checker.IsNil)

+

+	out, err = d.Cmd("inspect", "--format", "'{{.NetworkSettings.Networks.bridge.GlobalIPv6Address}}'", "ipv6test")

+	c.Assert(err, checker.IsNil)

+	c.Assert(strings.Trim(out, " \r\n'"), checker.Equals, "2001:db8:1::aabb:ccdd:eeff")

+

+	err = teardownV6()

+	c.Assert(err, checker.IsNil)

+}

+

 func (s *DockerDaemonSuite) TestDaemonLogLevelWrong(c *check.C) {

 	c.Assert(s.d.Start("--log-level=bogus"), check.NotNil, check.Commentf("Daemon shouldn't start with wrong log level"))

 }