.addEqualityGroup(Funnels.longFunnel())
        .addEqualityGroup(Funnels.unencodedCharsFunnel())
        .addEqualityGroup(Funnels.stringFunnel(UTF_8))
        .addEqualityGroup(Funnels.stringFunnel(US_ASCII))
        .addEqualityGroup(
            Funnels.sequentialFunnel(Funnels.integerFunnel()),
            SerializableTester.reserialize(Funnels.sequentialFunnel(Funnels.integerFunnel())))

      Funnel<? super T> funnel, long expectedInsertions, double fpp) {
    return create(funnel, expectedInsertions, fpp, BloomFilterStrategies.MURMUR128_MITZ_64);
  }

  @VisibleForTesting
  static <T extends @Nullable Object> BloomFilter<T> create(
      Funnel<? super T> funnel, long expectedInsertions, double fpp, Strategy strategy) {
    checkNotNull(funnel);
    checkArgument(

        .addEqualityGroup(BloomFilter.create(Funnels.byteArrayFunnel(), 100, 0.01))
        .addEqualityGroup(BloomFilter.create(Funnels.byteArrayFunnel(), 100, 0.02))
        .addEqualityGroup(BloomFilter.create(Funnels.byteArrayFunnel(), 200, 0.01))
        .addEqualityGroup(BloomFilter.create(Funnels.byteArrayFunnel(), 200, 0.02))
        .addEqualityGroup(BloomFilter.create(Funnels.unencodedCharsFunnel(), 100, 0.01))

              + Integer.toHexString(expected)
              + " got: "
              + Integer.toHexString(verification));
    }
  }

  static final Funnel<Object> BAD_FUNNEL =
      new Funnel<Object>() {
        @Override
        public void funnel(Object object, PrimitiveSink bytePrimitiveSink) {
          bytePrimitiveSink.putInt(object.hashCode());
        }
      };

  enum RandomHasherAction {

    HashFn hf =
        new HashFn() {
          @Override
          public byte[] hash(byte[] input, int seed) {
            Hasher hasher = murmur3_32(seed).newHasher();
            Funnels.byteArrayFunnel().funnel(input, hasher);
            return hasher.hash().asBytes();
          }
        };
    // Murmur3A, MurmurHash3 for x86, 32-bit (MurmurHash3_x86_32)

See [architecture doc](../architecture/ambient/ztunnel-cni-lifecycle.md).

## Reference

### Design details

Broadly, `istio-cni` accomplishes ambient redirection by instructing ztunnel to set up sockets within the application pod network namespace, where:

- one end of the socket is in the application pod
- and the other end is in ztunnel's pod

and setting up iptables rules to funnel traffic thru that socket "tube" to ztunnel and back.

If there is no waypoint, ztunnel will enforce RBAC policies against the request.

If all checks pass, ztunnel will open a connection to the target. This will spoof the source IP (from `Forwarded` for waypoints, or the incoming IP otherwise).
Once the connection is established we return a 200 HTTP code, and bi-directionally copy data to/from the tunnel to the destination.

## Certificates

local queries = (import './queries.libsonnet').queries({
  container: "istio-proxy",
  pod: "ztunnel-.*",
  component: "ztunnel",
  app: "ztunnel",
});

dashboard.new('Istio Ztunnel Dashboard')
+ g.dashboard.withPanels(
  grid.makeGrid([
    row.new('Process')
    + row.withPanels([
      panels.timeSeries.base('Ztunnel Versions', queries.istioBuild, 'Version number of each running instance'),

```mermaid
graph TD;
src[src pod]-->|plaintext port|ztunnel{"ztunnel (L4 policy applied here)"}
ztunnel{ztunnel}-->|TLS|wp{waypoint}
wp-->|mTLS|ztunnel
ztunnel-->|plaintext|dst[dst pod]
```

And here's an example of an authenticated request to a captured destination:

```mermaid
graph TD;
src[src pod]-->|15008|ztunnel{ztunnel}
ztunnel-->|HBONE|dwp{"destination waypoint (all policy applied here)"}

1. Immediately upon starting a drain, `ztunnel-old` will close its listeners. Now only `ztunnel-new` is listening. Critically, at all times there was at least one ztunnel listening.
1. While `ztunnel-old` will not accept *new* connections, it will continue processing existing connections.
1. After `drain period` seconds, `ztunnel-old` will forcefully terminate any outstanding connections.

> [!NOTE]