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Windows "host-gw" and "vxlan" support
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    - Add Windows host-gw
        (*) patch for #921
    - Add windows vxlan
        (*) patch for #922

Co-authored-by: rakelkar <rakelkar@outlook.com>
Co-authored-by: madhanrm <madhanrajm@outlook.com>
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@thxCode @madhanrm
3 people authored and frank committed Nov 6, 2018
1 parent 6d72802 commit e6fc2a2
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Showing 6 changed files with 905 additions and 11 deletions.
9 changes: 5 additions & 4 deletions Documentation/backends.md
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Expand Up @@ -19,10 +19,11 @@ Use in-kernel VXLAN to encapsulate the packets.

Type and options:
* `Type` (string): `vxlan`
* `VNI` (number): VXLAN Identifier (VNI) to be used. Defaults to 1.
* `Port` (number): UDP port to use for sending encapsulated packets. Defaults to kernel default, currently 8472.
* `GBP` (Boolean): Enable [VXLAN Group Based Policy](https://github.com/torvalds/linux/commit/3511494ce2f3d3b77544c79b87511a4ddb61dc89). Defaults to `false`.
* `DirectRouting` (Boolean): Enable direct routes (like `host-gw`) when the hosts are on the same subnet. VXLAN will only be used to encapsulate packets to hosts on different subnets. Defaults to `false`.
* `VNI` (number): VXLAN Identifier (VNI) to be used. On Linux, defaults to 1. On Windows should be greater than or equal to 4096.
* `Port` (number): UDP port to use for sending encapsulated packets. On Linux, defaults to kernel default, currently 8472, but on Windows, must be 4789.
* `GBP` (Boolean): Enable [VXLAN Group Based Policy](https://github.com/torvalds/linux/commit/3511494ce2f3d3b77544c79b87511a4ddb61dc89). Defaults to `false`. GBP is not supported on Windows
* `DirectRouting` (Boolean): Enable direct routes (like `host-gw`) when the hosts are on the same subnet. VXLAN will only be used to encapsulate packets to hosts on different subnets. Defaults to `false`. DirectRouting is not supported on Windows.
* `MacPrefix` (String): Only use on Windows, set to the MAC prefix. Defaults to `0E-2A`.

### host-gw

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237 changes: 232 additions & 5 deletions backend/hostgw/hostgw_windows.go
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@@ -1,6 +1,4 @@
// +build windows

// Copyright 2015 flannel authors
// Copyright 2018 flannel authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
Expand All @@ -13,14 +11,243 @@
// 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/pkg/ip"
"github.com/coreos/flannel/subnet"
log "github.com/golang/glog"
"github.com/juju/errors"
"github.com/rakelkar/gonetsh/netroute"
"github.com/rakelkar/gonetsh/netsh"
"golang.org/x/net/context"
"k8s.io/apimachinery/pkg/util/json"
"k8s.io/apimachinery/pkg/util/wait"
utilexec "k8s.io/utils/exec"
)

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: %+v", cfg)

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{
DestinationSubnet: lease.Subnet.ToIPNet(),
GatewayAddress: 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.New(utilexec.New())
createNewNetwork := true
expectedSubnet := n.SubnetLease.Subnet
expectedAddressPrefix := expectedSubnet.String()
expectedGatewayAddress := (expectedSubnet.IP + 1).String()
expectedPodGatewayAddress := expectedSubnet.IP + 2
networkName := cfg.Name
var waitErr, lastErr error

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)
}

// Wait for the network to populate Management IP
log.Infof("Waiting to get ManagementIP from HNSNetwork %s", networkName)
waitErr = wait.Poll(500*time.Millisecond, 5*time.Second, func() (done bool, err error) {
newNetwork, lastErr = hcsshim.HNSNetworkRequest("GET", newNetwork.Id, "")
return newNetwork != nil && len(newNetwork.ManagementIP) != 0, nil
})
if waitErr == wait.ErrWaitTimeout {
return nil, errors.Annotatef(lastErr, "timeout, failed to get management IP from HNSNetwork %s", networkName)
}

// Wait for the interface with the management IP
log.Infof("Waiting to get net interface for HNSNetwork %s (%s)", networkName, newNetwork.ManagementIP)
waitErr = wait.Poll(500*time.Millisecond, 5*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 for HNSNetwork %s (%s)", networkName, 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 expectedBridgeEndpoint, err = expectedBridgeEndpoint.Create(); err != nil {
return nil, errors.Annotatef(err, "failed to create bridge HNSEndpoint %s", bridgeEndpointName)
}

log.Infof("Created bridge HNSEndpoint %s", bridgeEndpointName)
}

// Wait for the bridgeEndpoint to attach to the host
log.Infof("Waiting to attach bridge endpoint %s to host", bridgeEndpointName)
waitErr = wait.Poll(500*time.Millisecond, 5*time.Second, func() (done bool, err error) {
lastErr = expectedBridgeEndpoint.HostAttach(1)
return lastErr == nil, nil
})
if waitErr == wait.ErrWaitTimeout {
return nil, errors.Annotatef(lastErr, "failed to hot attach bridge HNSEndpoint %s to host compartment", bridgeEndpointName)
}
log.Infof("Attached bridge endpoint %s to host successfully", bridgeEndpointName)

// 7. Enable forwarding on the host interface and endpoint
for _, interfaceIpAddress := range []string{expectedNetwork.ManagementIP, expectedBridgeEndpoint.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 interface 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 %s", netInterface.Name, interfaceIdx)
}
log.Infof("Enabled forwarding on %s index %s", netInterface.Name, interfaceIdx)
}

return n, nil
}

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