Add flag 'enableIPv4' to libnetwork.Network

Similar to EnableIPv6:
- Set it if EnableIPv4 is specified in a create request.
- Otherwise, set it if included in `default-network-opts`.
  - Apart from in a config-from network, so that it doesn't look
    like the API request set the field.
- Include the new field in  Network marshalling/unmarshalling test.

Signed-off-by: Rob Murray <rob.murray@docker.com>

daemon/network.go

@@ -316,18 +316,33 @@ func (daemon *Daemon) createNetwork(cfg *config.Config, create networktypes.Crea
 		}
 	}
 
+	enableIPv4 := create.ConfigFrom == nil
+	if create.EnableIPv4 != nil {
+		enableIPv4 = *create.EnableIPv4
+	} else if v, ok := networkOptions[netlabel.EnableIPv4]; ok {
+		var err error
+		if enableIPv4, err = strconv.ParseBool(v); err != nil {
+			return nil, errdefs.InvalidParameter(fmt.Errorf("driver-opt %q is not a valid bool", netlabel.EnableIPv4))
+		}
+	}
+	if !enableIPv4 && !daemon.config().Experimental && create.ConfigFrom == nil {
+		return nil, errdefs.InvalidParameter(
+			errors.New("IPv4 can only be disabled if experimental features are enabled"),
+		)
+	}
+
 	var enableIPv6 bool
 	if create.EnableIPv6 != nil {
 		enableIPv6 = *create.EnableIPv6
-	} else {
+	} else if v, ok := networkOptions[netlabel.EnableIPv6]; ok {
 		var err error
-		v, ok := networkOptions[netlabel.EnableIPv6]
-		if enableIPv6, err = strconv.ParseBool(v); ok && err != nil {
+		if enableIPv6, err = strconv.ParseBool(v); err != nil {
 			return nil, errdefs.InvalidParameter(fmt.Errorf("driver-opt %q is not a valid bool", netlabel.EnableIPv6))
 		}
 	}
 
 	nwOptions := []libnetwork.NetworkOption{
+		libnetwork.NetworkOptionEnableIPv4(enableIPv4),
 		libnetwork.NetworkOptionEnableIPv6(enableIPv6),
 		libnetwork.NetworkOptionDriverOpts(networkOptions),
 		libnetwork.NetworkOptionLabels(create.Labels),
@@ -620,6 +635,7 @@ func buildNetworkResource(nw *libnetwork.Network) networktypes.Inspect {
 		Created:    nw.Created(),
 		Scope:      nw.Scope(),
 		Driver:     nw.Type(),
+		EnableIPv4: nw.IPv4Enabled(),
 		EnableIPv6: nw.IPv6Enabled(),
 		IPAM:       buildIPAMResources(nw),
 		Internal:   nw.Internal(),

integration/internal/network/ops.go

@@ -11,6 +11,14 @@ func WithDriver(driver string) func(*network.CreateOptions) {
 	}
 }
 
+// WithIPv4 enables/disables IPv4 on the network
+func WithIPv4(enable bool) func(*network.CreateOptions) {
+	return func(n *network.CreateOptions) {
+		enableIPv4 := enable
+		n.EnableIPv4 = &enableIPv4
+	}
+}
+
 // WithIPv6 Enables IPv6 on the network
 func WithIPv6() func(*network.CreateOptions) {
 	return func(n *network.CreateOptions) {

libnetwork/libnetwork_internal_test.go

@@ -29,6 +29,7 @@ func TestNetworkMarshalling(t *testing.T) {
 		ipamType:    "default",
 		addrSpace:   "viola",
 		networkType: "bridge",
+		enableIPv4:  true,
 		enableIPv6:  true,
 		persist:     true,
 		configOnly:  true,
@@ -138,7 +139,7 @@ func TestNetworkMarshalling(t *testing.T) {
 	}
 
 	if n.name != nn.name || n.id != nn.id || n.networkType != nn.networkType || n.ipamType != nn.ipamType ||
-		n.addrSpace != nn.addrSpace || n.enableIPv6 != nn.enableIPv6 ||
+		n.addrSpace != nn.addrSpace || n.enableIPv4 != nn.enableIPv4 || n.enableIPv6 != nn.enableIPv6 ||
 		n.persist != nn.persist || !compareIpamConfList(n.ipamV4Config, nn.ipamV4Config) ||
 		!compareIpamInfoList(n.ipamV4Info, nn.ipamV4Info) || !compareIpamConfList(n.ipamV6Config, nn.ipamV6Config) ||
 		!compareIpamInfoList(n.ipamV6Info, nn.ipamV6Info) ||

libnetwork/netlabel/labels.go

@@ -30,6 +30,9 @@ const (
 	// where the interface name is represented by the string "IFNAME".
 	EndpointSysctls = Prefix + ".endpoint.sysctls"
 
+	// EnableIPv4 constant represents enabling IPV4 at network level
+	EnableIPv4 = Prefix + ".enable_ipv4"
+
 	// EnableIPv6 constant represents enabling IPV6 at network level
 	EnableIPv6 = Prefix + ".enable_ipv6"
 

libnetwork/network.go

@@ -187,6 +187,7 @@ type Network struct {
 	ipamV6Config     []*IpamConf
 	ipamV4Info       []*IpamInfo
 	ipamV6Info       []*IpamInfo
+	enableIPv4       bool
 	enableIPv6       bool
 	postIPv6         bool
 	epCnt            *endpointCnt
@@ -368,7 +369,7 @@ func (n *Network) validateConfiguration() error {
 		}
 		if n.ipamType != "" &&
 			n.ipamType != defaultIpamForNetworkType(n.networkType) ||
-			n.enableIPv6 ||
+			n.enableIPv4 || n.enableIPv6 ||
 			len(n.labels) > 0 || len(n.ipamOptions) > 0 ||
 			len(n.ipamV4Config) > 0 || len(n.ipamV6Config) > 0 {
 			return types.ForbiddenErrorf("user specified configurations are not supported if the network depends on a configuration network")
@@ -401,6 +402,7 @@ func (n *Network) validateConfiguration() error {
 
 // applyConfigurationTo applies network specific configurations.
 func (n *Network) applyConfigurationTo(to *Network) error {
+	to.enableIPv4 = n.enableIPv4
 	to.enableIPv6 = n.enableIPv6
 	if len(n.labels) > 0 {
 		to.labels = make(map[string]string, len(n.labels))
@@ -450,6 +452,7 @@ func (n *Network) CopyTo(o datastore.KVObject) error {
 	dstN.scope = n.scope
 	dstN.dynamic = n.dynamic
 	dstN.ipamType = n.ipamType
+	dstN.enableIPv4 = n.enableIPv4
 	dstN.enableIPv6 = n.enableIPv6
 	dstN.persist = n.persist
 	dstN.postIPv6 = n.postIPv6
@@ -539,6 +542,7 @@ func (n *Network) MarshalJSON() ([]byte, error) {
 	netMap["ipamType"] = n.ipamType
 	netMap["ipamOptions"] = n.ipamOptions
 	netMap["addrSpace"] = n.addrSpace
+	netMap["enableIPv4"] = n.enableIPv4
 	netMap["enableIPv6"] = n.enableIPv6
 	if n.generic != nil {
 		netMap["generic"] = n.generic
@@ -601,6 +605,12 @@ func (n *Network) UnmarshalJSON(b []byte) (err error) {
 		}
 	}
 	n.networkType = netMap["networkType"].(string)
+	if v, ok := netMap["enableIPv4"]; ok {
+		n.enableIPv4 = v.(bool)
+	} else {
+		// Set enableIPv4 for IPv4 networks created before the option was added.
+		n.enableIPv4 = len(n.ipamV4Info) > 0
+	}
 	n.enableIPv6 = netMap["enableIPv6"].(bool)
 
 	// if we weren't unmarshaling to netMap we could simply set n.labels
@@ -713,6 +723,9 @@ func NetworkOptionGeneric(generic map[string]interface{}) NetworkOption {
 		if n.generic == nil {
 			n.generic = make(map[string]interface{})
 		}
+		if val, ok := generic[netlabel.EnableIPv4]; ok {
+			n.enableIPv4 = val.(bool)
+		}
 		if val, ok := generic[netlabel.EnableIPv6]; ok {
 			n.enableIPv6 = val.(bool)
 		}
@@ -740,6 +753,17 @@ func NetworkOptionPersist(persist bool) NetworkOption {
 	}
 }
 
+// NetworkOptionEnableIPv4 returns an option setter to explicitly configure IPv4
+func NetworkOptionEnableIPv4(enableIPv4 bool) NetworkOption {
+	return func(n *Network) {
+		if n.generic == nil {
+			n.generic = make(map[string]interface{})
+		}
+		n.enableIPv4 = enableIPv4
+		n.generic[netlabel.EnableIPv4] = enableIPv4
+	}
+}
+
 // NetworkOptionEnableIPv6 returns an option setter to explicitly configure IPv6
 func NetworkOptionEnableIPv6(enableIPv6 bool) NetworkOption {
 	return func(n *Network) {
@@ -1842,6 +1866,13 @@ func (n *Network) Dynamic() bool {
 	return n.dynamic
 }
 
+func (n *Network) IPv4Enabled() bool {
+	n.mu.Lock()
+	defer n.mu.Unlock()
+
+	return n.enableIPv4
+}
+
 func (n *Network) IPv6Enabled() bool {
 	n.mu.Lock()
 	defer n.mu.Unlock()