Added flannel-ipv6-masq flag to enable IPv6 nat

Signed-off-by: Roberto Bonafiglia <roberto.bonafiglia@gmail.com>

pkg/agent/config/config.go

@@ -388,6 +388,7 @@ func get(ctx context.Context, envInfo *cmds.Agent, proxy proxy.Proxy) (*config.N
 		SELinux:                  envInfo.EnableSELinux,
 		ContainerRuntimeEndpoint: envInfo.ContainerRuntimeEndpoint,
 		FlannelBackend:           controlConfig.FlannelBackend,
+		FlannelIPv6Masq:          controlConfig.FlannelIPv6Masq,
 		ServerHTTPSPort:          controlConfig.HTTPSPort,
 	}
 	nodeConfig.FlannelIface = flannelIface

pkg/agent/flannel/flannel.go

@@ -39,7 +39,7 @@ const (
 	subnetFile = "/run/flannel/subnet.env"
 )
 
-func flannel(ctx context.Context, flannelIface *net.Interface, flannelConf, kubeConfigFile string, netMode int) error {
+func flannel(ctx context.Context, flannelIface *net.Interface, flannelConf, kubeConfigFile string, flannelIPv6Masq bool, netMode int) error {
 	extIface, err := LookupExtInterface(flannelIface, netMode)
 	if err != nil {
 		return err
@@ -71,7 +71,7 @@ func flannel(ctx context.Context, flannelIface *net.Interface, flannelConf, kube
 	go network.SetupAndEnsureIPTables(network.MasqRules(config.Network, bn.Lease()), 60)
 	go network.SetupAndEnsureIPTables(network.ForwardRules(config.Network.String()), 50)
 
-	if config.IPv6Network.String() != emptyIPv6Network {
+	if flannelIPv6Masq && config.IPv6Network.String() != emptyIPv6Network {
 		go network.SetupAndEnsureIP6Tables(network.MasqIP6Rules(config.IPv6Network, bn.Lease()), 60)
 		go network.SetupAndEnsureIP6Tables(network.ForwardRules(config.IPv6Network.String()), 50)
 	}

pkg/agent/flannel/setup.go

@@ -99,7 +99,7 @@ func Run(ctx context.Context, nodeConfig *config.Node, nodes typedcorev1.NodeInt
 		return errors.Wrap(err, "failed to check netMode for flannel")
 	}
 	go func() {
-		err := flannel(ctx, nodeConfig.FlannelIface, nodeConfig.FlannelConfFile, nodeConfig.AgentConfig.KubeConfigKubelet, netMode)
+		err := flannel(ctx, nodeConfig.FlannelIface, nodeConfig.FlannelConfFile, nodeConfig.AgentConfig.KubeConfigKubelet, nodeConfig.FlannelIPv6Masq, netMode)
 		if err != nil && !errors.Is(err, context.Canceled) {
 			logrus.Fatalf("flannel exited: %v", err)
 		}

pkg/cli/cmds/server.go

@@ -52,6 +52,7 @@ type Server struct {
 	DisableScheduler         bool
 	ServerURL                string
 	FlannelBackend           string
+	FlannelIPv6Masq          bool
 	DefaultLocalStoragePath  string
 	DisableCCM               bool
 	DisableNPC               bool
@@ -193,6 +194,11 @@ var ServerFlags = []cli.Flag{
 		Destination: &ServerConfig.FlannelBackend,
 		Value:       "vxlan",
 	},
+	cli.BoolFlag{
+		Name:        "flannel-ipv6-masq",
+		Usage:       "(networking) Enable IPv6 masquerading for pod",
+		Destination: &ServerConfig.FlannelIPv6Masq,
+	},
 	ServerToken,
 	cli.StringFlag{
 		Name:        "token-file",

pkg/cli/server/server.go

@@ -131,6 +131,7 @@ func run(app *cli.Context, cfg *cmds.Server, leaderControllers server.CustomCont
 	serverConfig.ControlConfig.AdvertiseIP = cfg.AdvertiseIP
 	serverConfig.ControlConfig.AdvertisePort = cfg.AdvertisePort
 	serverConfig.ControlConfig.FlannelBackend = cfg.FlannelBackend
+	serverConfig.ControlConfig.FlannelIPv6Masq = cfg.FlannelIPv6Masq
 	serverConfig.ControlConfig.ExtraCloudControllerArgs = cfg.ExtraCloudControllerArgs
 	serverConfig.ControlConfig.DisableCCM = cfg.DisableCCM
 	serverConfig.ControlConfig.DisableNPC = cfg.DisableNPC

pkg/daemons/config/types.go

@@ -34,6 +34,7 @@ type Node struct {
 	FlannelConfFile          string
 	FlannelConfOverride      bool
 	FlannelIface             *net.Interface
+	FlannelIPv6Masq          bool
 	Containerd               Containerd
 	Images                   string
 	AgentConfig              Agent
@@ -115,6 +116,7 @@ type CriticalControlArgs struct {
 	DisableNPC       bool
 	DisableServiceLB bool
 	FlannelBackend   string
+	FlannelIPv6Masq  bool
 	NoCoreDNS        bool
 	ServiceIPRange   *net.IPNet
 	ServiceIPRanges  []*net.IPNet