Add windows host-gw

    - patch for flannel-io#921

backend/hostgw/hostgw.go

@@ -13,7 +13,6 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
-// +build !windows
 
 package hostgw
 

backend/hostgw/hostgw_windows.go

@@ -1,5 +1,3 @@
-// +build windows
-
 // Copyright 2015 flannel authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
@@ -13,14 +11,235 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
-// +build windows
 
 package hostgw
 
 import (
+	"fmt"
+	"strconv"
+	"sync"
+	"time"
+
+	"github.com/Microsoft/hcsshim"
+	"github.com/coreos/flannel/backend"
+	"github.com/coreos/flannel/network/netroute"
+	"github.com/coreos/flannel/network/netsh"
+	"github.com/coreos/flannel/pkg/ip"
+	"github.com/coreos/flannel/subnet"
 	log "github.com/golang/glog"
+	"github.com/juju/errors"
+	"golang.org/x/net/context"
+	"k8s.io/apimachinery/pkg/util/json"
+	utilexec "k8s.io/utils/exec"
+	"k8s.io/apimachinery/pkg/util/wait"
 )
 
 func init() {
-	log.Infof("hostgw is not supported on this platform")
+	backend.Register("host-gw", New)
+}
+
+type HostgwBackend struct {
+	sm       subnet.Manager
+	extIface *backend.ExternalInterface
+}
+
+func New(sm subnet.Manager, extIface *backend.ExternalInterface) (backend.Backend, error) {
+	if !extIface.ExtAddr.Equal(extIface.IfaceAddr) {
+		return nil, fmt.Errorf("your PublicIP differs from interface IP, meaning that probably you're on a NAT, which is not supported by host-gw backend")
+	}
+
+	be := &HostgwBackend{
+		sm:       sm,
+		extIface: extIface,
+	}
+
+	return be, nil
+}
+
+func (be *HostgwBackend) RegisterNetwork(ctx context.Context, wg sync.WaitGroup, config *subnet.Config) (backend.Network, error) {
+	// 1. Parse configuration
+	cfg := struct {
+		Name          string
+		DNSServerList string
+	}{}
+	if len(config.Backend) > 0 {
+		if err := json.Unmarshal(config.Backend, &cfg); err != nil {
+			return nil, errors.Annotate(err, "error decoding windows host-gw backend config")
+		}
+	}
+	if len(cfg.Name) == 0 {
+		cfg.Name = "cbr0"
+	}
+	log.Infof("HOST-GW config: Name=%s DNSServerList=%s", cfg.Name, cfg.DNSServerList)
+
+	n := &backend.RouteNetwork{
+		SimpleNetwork: backend.SimpleNetwork{
+			ExtIface: be.extIface,
+		},
+		SM:          be.sm,
+		BackendType: "host-gw",
+		Mtu:         be.extIface.Iface.MTU,
+		LinkIndex:   be.extIface.Iface.Index,
+	}
+	n.GetRoute = func(lease *subnet.Lease) *netroute.Route {
+		return &netroute.Route{
+			Dst:       lease.Subnet.ToIPNet(),
+			Gw:        lease.Attrs.PublicIP.ToIP(),
+			LinkIndex: n.LinkIndex,
+		}
+	}
+
+	// 2. Acquire the lease form subnet manager
+	attrs := subnet.LeaseAttrs{
+		PublicIP:    ip.FromIP(be.extIface.ExtAddr),
+		BackendType: "host-gw",
+	}
+
+	l, err := be.sm.AcquireLease(ctx, &attrs)
+	switch err {
+	case nil:
+		n.SubnetLease = l
+
+	case context.Canceled, context.DeadlineExceeded:
+		return nil, err
+
+	default:
+		return nil, errors.Annotate(err, "failed to acquire lease")
+	}
+
+	// 3. Check if the network exists and has the expected settings
+	netshHelper := netsh.NewHelper(utilexec.New())
+	createNewNetwork := true
+	expectedSubnet := n.SubnetLease.Subnet
+	expectedAddressPrefix := expectedSubnet.String()
+	expectedGatewayAddress := (expectedSubnet.IP + 1).String()
+	expectedPodGatewayAddress := expectedSubnet.IP + 2
+	networkName := cfg.Name
+
+	existingNetwork, err := hcsshim.GetHNSNetworkByName(networkName)
+	if err == nil {
+		for _, subnet := range existingNetwork.Subnets {
+			if subnet.AddressPrefix == expectedAddressPrefix && subnet.GatewayAddress == expectedGatewayAddress {
+				createNewNetwork = false
+				log.Infof("Found existing HNSNetwork %s", networkName)
+				break
+			}
+		}
+	}
+
+	// 4. Create a new HNSNetwork
+	expectedNetwork := existingNetwork
+	if createNewNetwork {
+		if existingNetwork != nil {
+			if _, err := existingNetwork.Delete(); err != nil {
+				return nil, errors.Annotatef(err, "failed to delete existing HNSNetwork %s", networkName)
+			}
+			log.Infof("Deleted stale HNSNetwork %s", networkName)
+		}
+
+		expectedNetwork = &hcsshim.HNSNetwork{
+			Name:          networkName,
+			Type:          "L2Bridge",
+			DNSServerList: cfg.DNSServerList,
+			Subnets: []hcsshim.Subnet{
+				{
+					AddressPrefix:  expectedAddressPrefix,
+					GatewayAddress: expectedGatewayAddress,
+				},
+			},
+		}
+		jsonRequest, err := json.Marshal(expectedNetwork)
+		if err != nil {
+			return nil, errors.Annotatef(err, "failed to marshal %+v", expectedNetwork)
+		}
+
+		log.Infof("Attempting to create HNSNetwork %s", string(jsonRequest))
+		newNetwork, err := hcsshim.HNSNetworkRequest("POST", "", string(jsonRequest))
+		if err != nil {
+			return nil, errors.Annotatef(err, "failed to create HNSNetwork %s", networkName)
+		}
+
+		var waitErr, lastErr error
+		// Wait for the network to populate Management IP
+		waitErr = wait.Poll(1*time.Second, 10*time.Second, func() (done bool, err error) {
+			newNetwork, lastErr = hcsshim.HNSNetworkRequest("GET", newNetwork.Id, "")
+			return len(newNetwork.ManagementIP) == 0, nil
+		})
+		if waitErr == wait.ErrWaitTimeout {
+			return nil, errors.Annotatef(lastErr, "timeout, failed to get management IP from HNSNetwork by ID: %s", newNetwork.Id)
+		}
+
+		// Wait for the interface with the management IP
+		waitErr = wait.Poll(1*time.Second, 10*time.Second, func() (done bool, err error) {
+			_, lastErr = netshHelper.GetInterfaceByIP(newNetwork.ManagementIP)
+			return lastErr == nil, nil
+		})
+		if waitErr == wait.ErrWaitTimeout {
+			return nil, errors.Annotatef(lastErr, "timeout, failed to get net interface by IP: %s", newNetwork.ManagementIP)
+		}
+
+		log.Infof("Created HNSNetwork %s", networkName)
+		expectedNetwork = newNetwork
+	}
+
+	// 5. Ensure a 1.2 endpoint on this network in the host compartment
+	createNewBridgeEndpoint := true
+	bridgeEndpointName := networkName + "_ep"
+	existingBridgeEndpoint, err := hcsshim.GetHNSEndpointByName(bridgeEndpointName)
+	if err == nil && existingBridgeEndpoint.IPAddress.String() == expectedPodGatewayAddress.String() {
+		log.Infof("Found existing bridge HNSEndpoint %s", bridgeEndpointName)
+		createNewBridgeEndpoint = false
+	}
+
+	// 6. Create a bridge HNSEndpoint
+	expectedBridgeEndpoint := existingBridgeEndpoint
+	if createNewBridgeEndpoint {
+		if existingBridgeEndpoint != nil {
+			if _, err = existingBridgeEndpoint.Delete(); err != nil {
+				return nil, errors.Annotatef(err, "failed to delete existing bridge HNSEndpoint %s", bridgeEndpointName)
+			}
+			log.Infof("Deleted stale bridge HNSEndpoint %s", bridgeEndpointName)
+		}
+
+		expectedBridgeEndpoint = &hcsshim.HNSEndpoint{
+			Name:           bridgeEndpointName,
+			IPAddress:      expectedPodGatewayAddress.ToIP(),
+			VirtualNetwork: expectedNetwork.Id,
+		}
+
+		log.Infof("Attempting to create bridge HNSEndpoint %+v", expectedBridgeEndpoint)
+		if existingBridgeEndpoint, err = expectedBridgeEndpoint.Create(); err != nil {
+			return nil, errors.Annotatef(err, "failed to create bridge HNSEndpoint %s", bridgeEndpointName)
+		}
+
+		log.Infof("Created bridge HNSEndpoint %s", bridgeEndpointName)
+	}
+
+	if err = expectedBridgeEndpoint.HostAttach(1); err != nil {
+		return nil, errors.Annotatef(err, "failed to hot attach bridge HNSEndpoint %s to host compartment", bridgeEndpointName)
+	}
+	log.Infof("Attached bridge endpoint %s to host", bridgeEndpointName)
+
+	// 7. Enable forwarding on the host interface and endpoint
+	for _, interfaceIpAddress := range []string{expectedNetwork.ManagementIP, existingBridgeEndpoint.IPAddress.String()} {
+		netInterface, err := netshHelper.GetInterfaceByIP(interfaceIpAddress)
+		if err != nil {
+			return nil, errors.Annotatef(err, "failed to find interface for IP Address %s", interfaceIpAddress)
+		}
+		log.Infof("Found %v NetshInterface with IP %s", netInterface, interfaceIpAddress)
+
+		// When a new hns network is created, the interface is modified, esp the name, index
+		if expectedNetwork.ManagementIP == netInterface.IpAddress {
+			n.LinkIndex = netInterface.Idx
+			n.Name = netInterface.Name
+		}
+
+		interfaceIdx := strconv.Itoa(netInterface.Idx)
+		if err := netshHelper.EnableForwarding(interfaceIdx); err != nil {
+			return nil, errors.Annotatef(err, "failed to enable forwarding on %s index %d", netInterface.Name, interfaceIdx)
+		}
+		log.Infof("Enabled forwarding on %s index %d", netInterface.Name, interfaceIdx)
+	}
+
+	return n, nil
 }