Support NDP proxying on bridge networks

- Proxying is enabled via the network label com.docker.network.bridge.ndp_proxy_interface=<interface>

fixes #1159

Signed-off-by: Zvi "CtrlZvi" Effron <[email protected]>

Author: CtrlZvi

drivers/bridge/bridge.go

@@ -58,6 +58,7 @@ type networkConfiguration struct {
 	BridgeName         string
 	EnableIPv6         bool
 	EnableIPMasquerade bool
+	NDPProxyInterface  string
 	EnableICC          bool
 	Mtu                int
 	DefaultBindingIP   net.IP
@@ -215,6 +216,8 @@ func (c *networkConfiguration) fromLabels(labels map[string]string) error {
 			if c.EnableIPMasquerade, err = strconv.ParseBool(value); err != nil {
 				return parseErr(label, value, err.Error())
 			}
+		case NDPProxyInterface:
+			c.NDPProxyInterface = value
 		case EnableICC:
 			if c.EnableICC, err = strconv.ParseBool(value); err != nil {
 				return parseErr(label, value, err.Error())
@@ -680,6 +683,7 @@ func (d *driver) createNetwork(config *networkConfiguration) error {
 	bridgeSetup.queueStep(setupBridgeIPv4)
 
 	enableIPv6Forwarding := d.config.EnableIPForwarding && config.AddressIPv6 != nil
+	enableNDPProxying := config.NDPProxyInterface != "" && config.AddressIPv6 != nil
 
 	// Conditionally queue setup steps depending on configuration values.
 	for _, step := range []struct {
@@ -699,6 +703,9 @@ func (d *driver) createNetwork(config *networkConfiguration) error {
 		// Enable IPv6 Forwarding
 		{enableIPv6Forwarding, setupIPv6Forwarding},
 
+		// Enable NDP Proxying
+		{enableNDPProxying, setupNDPProxying},
+
 		// Setup Loopback Adresses Routing
 		{!d.config.EnableUserlandProxy, setupLoopbackAdressesRouting},
 
@@ -1019,6 +1026,27 @@ func (d *driver) CreateEndpoint(nid, eid string, ifInfo driverapi.InterfaceInfo,
 		}
 	}
 
+	// Add a neighbor proxy if using NDP proxying
+	if config.NDPProxyInterface != "" && config.EnableIPv6 {
+		link, err := d.nlh.LinkByName(config.NDPProxyInterface)
+		if err != nil {
+			return err
+		}
+		neighbor := netlink.Neigh{
+			LinkIndex:    link.Attrs().Index,
+			Family:       netlink.FAMILY_V6,
+			State:        netlink.NUD_PERMANENT,
+			Type:         netlink.NDA_UNSPEC,
+			Flags:        netlink.NTF_PROXY,
+			IP:           endpoint.addrv6.IP,
+			HardwareAddr: endpoint.macAddress,
+		}
+		if err := d.nlh.NeighAdd(&neighbor); err != nil {
+			logrus.Warnf("could not add the neighbor proxy: %v", err)
+			return err
+		}
+	}
+
 	if err = d.storeUpdate(endpoint); err != nil {
 		return fmt.Errorf("failed to save bridge endpoint %s to store: %v", endpoint.id[0:7], err)
 	}
@@ -1077,6 +1105,24 @@ func (d *driver) DeleteEndpoint(nid, eid string) error {
 		}
 	}()
 
+	// Try removal of neighbor proxy. Discard error: it is a best effort.
+	// Also make sure defer does not see this error either.
+	if n.config.NDPProxyInterface != "" && n.config.EnableIPv6 {
+		link, err := d.nlh.LinkByName(n.config.NDPProxyInterface)
+		if err == nil {
+			neighbor := netlink.Neigh{
+				LinkIndex:    link.Attrs().Index,
+				Family:       netlink.FAMILY_V6,
+				State:        netlink.NUD_PERMANENT,
+				Type:         netlink.NDA_UNSPEC,
+				Flags:        netlink.NTF_PROXY,
+				IP:           ep.addrv6.IP,
+				HardwareAddr: ep.macAddress,
+			}
+			d.nlh.NeighDel(&neighbor)
+		}
+	}
+
 	// Try removal of link. Discard error: it is a best effort.
 	// Also make sure defer does not see this error either.
 	if link, err := d.nlh.LinkByName(ep.srcName); err == nil {

drivers/bridge/bridge_store.go

@@ -136,6 +136,7 @@ func (ncfg *networkConfiguration) MarshalJSON() ([]byte, error) {
 	nMap["BridgeName"] = ncfg.BridgeName
 	nMap["EnableIPv6"] = ncfg.EnableIPv6
 	nMap["EnableIPMasquerade"] = ncfg.EnableIPMasquerade
+	nMap["NDPProxyInterface"] = ncfg.NDPProxyInterface
 	nMap["EnableICC"] = ncfg.EnableICC
 	nMap["Mtu"] = ncfg.Mtu
 	nMap["Internal"] = ncfg.Internal
@@ -185,6 +186,9 @@ func (ncfg *networkConfiguration) UnmarshalJSON(b []byte) error {
 	ncfg.BridgeName = nMap["BridgeName"].(string)
 	ncfg.EnableIPv6 = nMap["EnableIPv6"].(bool)
 	ncfg.EnableIPMasquerade = nMap["EnableIPMasquerade"].(bool)
+	if v, ok := nMap["NDPProxyInterface"]; ok {
+		ncfg.NDPProxyInterface = v.(string)
+	}
 	ncfg.EnableICC = nMap["EnableICC"].(bool)
 	ncfg.Mtu = int(nMap["Mtu"].(float64))
 	if v, ok := nMap["Internal"]; ok {

drivers/bridge/bridge_test.go

@@ -16,6 +16,7 @@ import (
 	"github.com/docker/libnetwork/options"
 	"github.com/docker/libnetwork/testutils"
 	"github.com/docker/libnetwork/types"
+	"github.com/vishvananda/netlink"
 )
 
 func init() {
@@ -269,13 +270,15 @@ func TestCreateFullOptionsLabels(t *testing.T) {
 	gwV6s := "2001:db8:2600:2700:2800::25/80"
 	nwV6, _ := types.ParseCIDR(nwV6s)
 	gwV6, _ := types.ParseCIDR(gwV6s)
+	ndpPxyIface := "lo"
 
 	labels := map[string]string{
 		BridgeName:         DefaultBridgeName,
 		DefaultBridge:      "true",
 		EnableICC:          "true",
 		EnableIPMasquerade: "true",
 		DefaultBindingIP:   bndIPs,
+		NDPProxyInterface:  ndpPxyIface,
 	}
 
 	netOption := make(map[string]interface{})
@@ -318,6 +321,10 @@ func TestCreateFullOptionsLabels(t *testing.T) {
 		t.Fatalf("incongruent EnableIPMasquerade in bridge network")
 	}
 
+	if nw.config.NDPProxyInterface != ndpPxyIface {
+		t.Fatalf("incongruend NDPProxyInterface in bridge network")
+	}
+
 	bndIP := net.ParseIP(bndIPs)
 	if !bndIP.Equal(nw.config.DefaultBindingIP) {
 		t.Fatalf("Unexpected: %v", nw.config.DefaultBindingIP)
@@ -347,6 +354,22 @@ func TestCreateFullOptionsLabels(t *testing.T) {
 	if te.Interface().AddressIPv6().IP.String() != "2001:db8:2600:2700:2800:aabb:ccdd:eeff" {
 		t.Fatalf("Unexpected endpoint IPv6 address: %v", te.Interface().AddressIPv6().IP)
 	}
+
+	// Check that the neighbor proxy was created by trying to delete it,
+	// because netlink.NeighList currently can't list proxies.
+	link, _ := d.nlh.LinkByName(ndpPxyIface)
+	err = d.nlh.NeighDel(&netlink.Neigh{
+		LinkIndex:    link.Attrs().Index,
+		Family:       netlink.FAMILY_V6,
+		State:        netlink.NUD_PERMANENT,
+		Type:         netlink.NDA_UNSPEC,
+		Flags:        netlink.NTF_PROXY,
+		IP:           te.Interface().AddressIPv6().IP,
+		HardwareAddr: te.Interface().MacAddress(),
+	})
+	if err != nil {
+		t.Fatalf("Cannot delete neighbor proxy, suggesting it wasn't created: %v", err)
+	}
 }
 
 func TestCreate(t *testing.T) {

drivers/bridge/labels.go

@@ -7,6 +7,9 @@ const (
 	// EnableIPMasquerade label for bridge driver
 	EnableIPMasquerade = "com.docker.network.bridge.enable_ip_masquerade"
 
+	// NDPProxyInterface label for bridge driver
+	NDPProxyInterface = "com.docker.network.bridge.ndp_proxy_interface"
+
 	// EnableICC label
 	EnableICC = "com.docker.network.bridge.enable_icc"
 

drivers/bridge/setup_ipv6.go

@@ -18,6 +18,9 @@ const (
 	ipv6ForwardConfPerm    = 0644
 	ipv6ForwardConfDefault = "/proc/sys/net/ipv6/conf/default/forwarding"
 	ipv6ForwardConfAll     = "/proc/sys/net/ipv6/conf/all/forwarding"
+	ndpProxyConfPerm       = 0644
+	ndpProxyConfDefault    = "/proc/sys/net/ipv6/conf/default/proxy_ndp"
+	ndpProxyConfAll        = "/proc/sys/net/ipv6/conf/all/proxy_ndp"
 )
 
 func init() {
@@ -117,3 +120,31 @@ func setupIPv6Forwarding(config *networkConfiguration, i *bridgeInterface) error
 
 	return nil
 }
+
+func setupNDPProxying(config *networkConfiguration, i *bridgeInterface) error {
+	// Get current NDP default proxying setup
+	ndpProxyDataDefault, err := ioutil.ReadFile(ndpProxyConfDefault)
+	if err != nil {
+		return fmt.Errorf("Cannot read NDP default proxying setup: %v", err)
+	}
+	// Enable NDP default proxying only if it is not already enabled
+	if ndpProxyDataDefault[0] != '1' {
+		if err := ioutil.WriteFile(ndpProxyConfDefault, []byte{'1', '\n'}, ndpProxyConfPerm); err != nil {
+			logrus.Warnf("Unable to enable NDP default proxying: %v", err)
+		}
+	}
+
+	// Get current NDP all proxying setup
+	ndpProxyDataAll, err := ioutil.ReadFile(ndpProxyConfAll)
+	if err != nil {
+		return fmt.Errorf("Cannot read NDP all proxying setup: %v", err)
+	}
+	// Enable NDP all proxying only if it is not already enabled
+	if ndpProxyDataAll[0] != '1' {
+		if err := ioutil.WriteFile(ndpProxyConfAll, []byte{'1', '\n'}, ndpProxyConfPerm); err != nil {
+			logrus.Warnf("Unable to enable NDP all proxying: %v", err)
+		}
+	}
+
+	return nil
+}