mirror of
https://github.com/k3s-io/k3s.git
synced 2024-06-07 19:41:36 +00:00
261 lines
8.1 KiB
Go
261 lines
8.1 KiB
Go
package flannel
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import (
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"context"
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"fmt"
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"net"
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"os"
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"path/filepath"
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goruntime "runtime"
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"strings"
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"github.com/k3s-io/k3s/pkg/agent/util"
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"github.com/k3s-io/k3s/pkg/daemons/config"
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"github.com/pkg/errors"
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"github.com/sirupsen/logrus"
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v1 "k8s.io/api/core/v1"
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metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
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"k8s.io/apimachinery/pkg/fields"
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"k8s.io/apimachinery/pkg/runtime"
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"k8s.io/apimachinery/pkg/watch"
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typedcorev1 "k8s.io/client-go/kubernetes/typed/core/v1"
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"k8s.io/client-go/tools/cache"
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toolswatch "k8s.io/client-go/tools/watch"
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utilsnet "k8s.io/utils/net"
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)
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const (
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flannelConf = `{
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"Network": "%CIDR%",
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"EnableIPv6": %IPV6_ENABLED%,
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"EnableIPv4": %IPV4_ENABLED%,
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"IPv6Network": "%CIDR_IPV6%",
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"Backend": %backend%
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}
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`
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hostGWBackend = `{
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"Type": "host-gw"
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}`
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tailscaledBackend = `{
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"Type": "extension",
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"PostStartupCommand": "tailscale set --accept-routes --advertise-routes=%Routes%",
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"ShutdownCommand": "tailscale down"
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}`
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wireguardNativeBackend = `{
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"Type": "wireguard",
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"PersistentKeepaliveInterval": %PersistentKeepaliveInterval%,
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"Mode": "%Mode%"
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}`
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emptyIPv6Network = "::/0"
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ipv4 = iota
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ipv6
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)
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func Prepare(ctx context.Context, nodeConfig *config.Node) error {
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if err := createCNIConf(nodeConfig.AgentConfig.CNIConfDir, nodeConfig); err != nil {
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return err
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}
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return createFlannelConf(nodeConfig)
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}
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func Run(ctx context.Context, nodeConfig *config.Node, nodes typedcorev1.NodeInterface) error {
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logrus.Infof("Starting flannel with backend %s", nodeConfig.FlannelBackend)
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if err := waitForPodCIDR(ctx, nodeConfig.AgentConfig.NodeName, nodes); err != nil {
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return errors.Wrap(err, "flannel failed to wait for PodCIDR assignment")
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}
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netMode, err := findNetMode(nodeConfig.AgentConfig.ClusterCIDRs)
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if err != nil {
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return errors.Wrap(err, "failed to check netMode for flannel")
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}
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go func() {
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err := flannel(ctx, nodeConfig.FlannelIface, nodeConfig.FlannelConfFile, nodeConfig.AgentConfig.KubeConfigKubelet, nodeConfig.FlannelIPv6Masq, netMode)
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if err != nil && !errors.Is(err, context.Canceled) {
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logrus.Errorf("flannel exited: %v", err)
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os.Exit(1)
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}
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os.Exit(0)
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}()
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return nil
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}
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// waitForPodCIDR watches nodes with this node's name, and returns when the PodCIDR has been set.
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func waitForPodCIDR(ctx context.Context, nodeName string, nodes typedcorev1.NodeInterface) error {
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fieldSelector := fields.Set{metav1.ObjectNameField: nodeName}.String()
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lw := &cache.ListWatch{
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ListFunc: func(options metav1.ListOptions) (object runtime.Object, e error) {
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options.FieldSelector = fieldSelector
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return nodes.List(ctx, options)
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},
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WatchFunc: func(options metav1.ListOptions) (i watch.Interface, e error) {
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options.FieldSelector = fieldSelector
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return nodes.Watch(ctx, options)
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},
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}
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condition := func(ev watch.Event) (bool, error) {
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if n, ok := ev.Object.(*v1.Node); ok {
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return n.Spec.PodCIDR != "", nil
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}
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return false, errors.New("event object not of type v1.Node")
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}
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if _, err := toolswatch.UntilWithSync(ctx, lw, &v1.Node{}, nil, condition); err != nil {
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return errors.Wrap(err, "failed to wait for PodCIDR assignment")
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}
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logrus.Info("Flannel found PodCIDR assigned for node " + nodeName)
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return nil
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}
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func createCNIConf(dir string, nodeConfig *config.Node) error {
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logrus.Debugf("Creating the CNI conf in directory %s", dir)
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if dir == "" {
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return nil
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}
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p := filepath.Join(dir, "10-flannel.conflist")
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if nodeConfig.AgentConfig.FlannelCniConfFile != "" {
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logrus.Debugf("Using %s as the flannel CNI conf", nodeConfig.AgentConfig.FlannelCniConfFile)
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return util.CopyFile(nodeConfig.AgentConfig.FlannelCniConfFile, p, false)
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}
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cniConfJSON := cniConf
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if goruntime.GOOS == "windows" {
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extIface, err := LookupExtInterface(nodeConfig.FlannelIface, ipv4)
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if err != nil {
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return err
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}
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cniConfJSON = strings.ReplaceAll(cniConfJSON, "%IPV4_ADDRESS%", extIface.IfaceAddr.String())
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cniConfJSON = strings.ReplaceAll(cniConfJSON, "%CLUSTER_CIDR%", nodeConfig.AgentConfig.ClusterCIDR.String())
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cniConfJSON = strings.ReplaceAll(cniConfJSON, "%SERVICE_CIDR%", nodeConfig.AgentConfig.ServiceCIDR.String())
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}
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return util.WriteFile(p, cniConfJSON)
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}
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func createFlannelConf(nodeConfig *config.Node) error {
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var ipv4Enabled string
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logrus.Debugf("Creating the flannel configuration for backend %s in file %s", nodeConfig.FlannelBackend, nodeConfig.FlannelConfFile)
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if nodeConfig.FlannelConfFile == "" {
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return errors.New("Flannel configuration not defined")
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}
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if nodeConfig.FlannelConfOverride {
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logrus.Infof("Using custom flannel conf defined at %s", nodeConfig.FlannelConfFile)
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return nil
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}
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netMode, err := findNetMode(nodeConfig.AgentConfig.ClusterCIDRs)
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if err != nil {
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logrus.Fatalf("Flannel error checking netMode: %v", err)
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return err
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}
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if netMode == ipv4 || netMode == (ipv4+ipv6) {
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ipv4Enabled = "true"
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} else {
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ipv4Enabled = "false"
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}
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confJSON := strings.ReplaceAll(flannelConf, "%IPV4_ENABLED%", ipv4Enabled)
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if netMode == ipv4 {
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confJSON = strings.ReplaceAll(confJSON, "%CIDR%", nodeConfig.AgentConfig.ClusterCIDR.String())
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confJSON = strings.ReplaceAll(confJSON, "%IPV6_ENABLED%", "false")
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confJSON = strings.ReplaceAll(confJSON, "%CIDR_IPV6%", emptyIPv6Network)
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} else if netMode == (ipv4 + ipv6) {
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confJSON = strings.ReplaceAll(confJSON, "%IPV6_ENABLED%", "true")
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for _, cidr := range nodeConfig.AgentConfig.ClusterCIDRs {
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if utilsnet.IsIPv6(cidr.IP) {
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// Only one ipv6 range available. This might change in future: https://github.com/kubernetes/enhancements/issues/2593
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confJSON = strings.ReplaceAll(confJSON, "%CIDR_IPV6%", cidr.String())
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} else {
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confJSON = strings.ReplaceAll(confJSON, "%CIDR%", cidr.String())
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}
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}
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} else {
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confJSON = strings.ReplaceAll(confJSON, "%CIDR%", "0.0.0.0/0")
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confJSON = strings.ReplaceAll(confJSON, "%IPV6_ENABLED%", "true")
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for _, cidr := range nodeConfig.AgentConfig.ClusterCIDRs {
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if utilsnet.IsIPv6(cidr.IP) {
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// Only one ipv6 range available. This might change in future: https://github.com/kubernetes/enhancements/issues/2593
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confJSON = strings.ReplaceAll(confJSON, "%CIDR_IPV6%", cidr.String())
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}
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}
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}
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var backendConf string
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backendOptions := make(map[string]string)
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// precheck and error out unsupported flannel backends.
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switch nodeConfig.FlannelBackend {
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case config.FlannelBackendHostGW:
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case config.FlannelBackendTailscale:
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case config.FlannelBackendWireguardNative:
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if goruntime.GOOS == "windows" {
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return fmt.Errorf("unsupported flannel backend '%s' for Windows", nodeConfig.FlannelBackend)
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}
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}
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switch nodeConfig.FlannelBackend {
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case config.FlannelBackendVXLAN:
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backendConf = vxlanBackend
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case config.FlannelBackendHostGW:
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backendConf = hostGWBackend
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case config.FlannelBackendTailscale:
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var routes string
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switch netMode {
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case ipv4:
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routes = "$SUBNET"
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case (ipv4 + ipv6):
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routes = "$SUBNET,$IPV6SUBNET"
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case ipv6:
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routes = "$IPV6SUBNET"
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default:
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return fmt.Errorf("incorrect netMode for flannel tailscale backend")
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}
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backendConf = strings.ReplaceAll(tailscaledBackend, "%Routes%", routes)
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case config.FlannelBackendWireguardNative:
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mode, ok := backendOptions["Mode"]
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if !ok {
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mode = "separate"
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}
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keepalive, ok := backendOptions["PersistentKeepaliveInterval"]
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if !ok {
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keepalive = "25"
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}
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backendConf = strings.ReplaceAll(wireguardNativeBackend, "%Mode%", mode)
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backendConf = strings.ReplaceAll(backendConf, "%PersistentKeepaliveInterval%", keepalive)
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default:
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return fmt.Errorf("Cannot configure unknown flannel backend '%s'", nodeConfig.FlannelBackend)
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}
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confJSON = strings.ReplaceAll(confJSON, "%backend%", backendConf)
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logrus.Debugf("The flannel configuration is %s", confJSON)
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return util.WriteFile(nodeConfig.FlannelConfFile, confJSON)
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}
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// fundNetMode returns the mode (ipv4, ipv6 or dual-stack) in which flannel is operating
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func findNetMode(cidrs []*net.IPNet) (int, error) {
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dualStack, err := utilsnet.IsDualStackCIDRs(cidrs)
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if err != nil {
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return 0, err
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}
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if dualStack {
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return ipv4 + ipv6, nil
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}
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for _, cidr := range cidrs {
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if utilsnet.IsIPv4CIDR(cidr) {
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return ipv4, nil
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}
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if utilsnet.IsIPv6CIDR(cidr) {
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return ipv6, nil
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}
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}
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return 0, errors.New("Failed checking netMode")
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}
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