}

		case <-time.After(ztunnelKeepAliveCheckInterval):
			// do a short read, just to see if the connection to ztunnel is
			// still alive. As ztunnel shouldn't send anything unless we send
			// something first, we expect to get an os.ErrDeadlineExceeded error
			// here if the connection is still alive.
			// note that unlike tcp connections, reading is a good enough test here.
			_, err := conn.readMessage(time.Second / 100)

# Controllers

Istio has a variety of [controllers](https://kubernetes.io/docs/concepts/architecture/controller/), which basically watch some inputs and do something.
This can be reading from Kubernetes and writing other objects back, writing to proxies over XDS, etc.

Unfortunately, writing controllers is very error prone, even for seemingly simple cases.
To work around this, Istio has a variety of abstractions meant to make writing controllers easier.

## Clients

FROM ubuntu:jammy

ENV DEBIAN_FRONTEND=noninteractive

# Do not add more stuff to this list that isn't small or critically useful.
# If you occasionally need something on the container do
# sudo apt-get update && apt-get whichever

# hadolint ignore=DL3005,DL3008
RUN apt-get update && \
  apt-get install --no-install-recommends -y \
  ca-certificates \
  curl \
  iptables \
  iproute2 \
  iputils-ping \
  knot-dnsutils \
  netcat \

	}

	return pods, namespace, nil
}

func getClientForResource(resname, ns string, factory cmdutil.Factory) (*corev1client.CoreV1Client, string, string, string, error) {
	// Pod is referred to using something like "deployment/httpbin".  Use the kubectl
	// libraries to look up the resource name, find the pods it selects, and return
	// one of those pods.
	builder := factory.NewBuilder().

		// Add IP/port combo to set. Note that we set Replace to true - a pod ip/port combo already being
		// in the set is perfectly fine, and something we can always safely overwrite, so we will.
		if err := hostsideProbeSet.AddIP(pip, ipProto, podUID, true); err != nil {
			ipsetAddrErrs = append(ipsetAddrErrs, err)

	checkOutputFiles(t, testdir, checkFiles)
}

func runTestCmd(t *testing.T, createResourceFunc func(client kube.CLIClient), rev string, args []string) (string, error) {
	t.Helper()
	// TODO there is already probably something else that does this
	var out bytes.Buffer
	ctx := cli.NewFakeContext(&cli.NewFakeContextOption{
		IstioNamespace: "istio-system",
	})
	rootCmd := Cmd(ctx)
	rootCmd.SetArgs(args)

			"sidecar.istio.io/status": "something",
		},
		Labels: map[string]string{
			"testlabel": "true",
		},
		NodeName:            "test-node",
		InitContainerStatus: &brokenInitContainerTerminating,
	})

	brokenPodWaiting = makePod(makePodArgs{
		PodName: "broken-pod-waiting",
		Annotations: map[string]string{
			"sidecar.istio.io/status": "something",
		},
		NodeName:            "test-node",

  echo "Copying '${2}' to ${TARGET_OUT_LINUX}/ztunnel"
  cp -f "${2}" "${TARGET_OUT_LINUX}/ztunnel"
}

function maybe_build_ztunnel() {
  # TODO detect git changes or something to avoid unnecessarily building
  # BUILD_ZTUNNEL=1 with no BUILD_ZTUNNEL_REPO tries to infer BUILD_ZTUNNEL_REPO
  if [[ "${BUILD_ZTUNNEL_REPO:-}" == "" ]] && [[ "${BUILD_ZTUNNEL:-}" != "" ]]; then
    local ZTUNNEL_DIR

	// We don't want to constantly try to apply the iptables rules, which is unneeded and will fail.
	// Instead, we track which UIDs we repaired and skip them if already repaired.
	//
	// An alternative would be to write something to the Pod (status, annotation, etc).
	// However, this requires elevated privileges we want to avoid
	if uid, f := c.repairedPods[key]; f {
		if uid == pod.UID {
			log.Debugf("Skipping pod, already repaired")

	netns io.Closer
	fd    uintptr
	inode uint64
}

func (n *NetnsWithFd) Close() error {
	if n.netns == nil {
		return nil
	}

	ret := n.netns.Close()
	// set fd to invalid value, so if something uses it by mistake it will err
	uintZero := uintptr(0)
	n.fd = ^uintZero
	return ret
}

func (n *NetnsWithFd) Fd() uintptr {
	return n.fd
}

func (n *NetnsWithFd) Inode() uint64 {
	return n.inode