### 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.

iptables -t nat -N ISTIO_POSTRT
iptables -t nat -A POSTROUTING -j ISTIO_POSTRT

iptables -t nat -N ISTIO_POSTRT
iptables -t nat -A POSTROUTING -j ISTIO_POSTRT
iptables -t nat -A ISTIO_POSTRT -m owner --socket-exists -p tcp -m set --match-set istio-inpod-probes-v4 dst -j SNAT --to-source 169.254.7.127
ip6tables -t nat -N ISTIO_POSTRT
ip6tables -t nat -A POSTROUTING -j ISTIO_POSTRT

			./pkg/istio-agent/... | sort | uniq |\
		grep -Pv '^k8s.io/(utils|klog|apimachinery)/' |\
		grep -Pv 'envoy/type/|envoy/annotations|envoy/config/core/' |\
		grep -Pv 'envoy/extensions/transport_sockets/tls/' |\
		grep -Pv 'envoy/service/discovery/v3' |\
		grep -Pv 'envoy/extensions/wasm/' |\
		grep -Pv 'envoy/extensions/filters/(http|network)/wasm/' |\

message Sysctl {
  // Name of a property to set
  optional string name = 1;

  // Value of a property to set
  optional string value = 2;
}

// TCPSocketAction describes an action based on opening a socket
message TCPSocketAction {
  // Number or name of the port to access on the container.
  // Number must be in the range 1 to 65535.
  // Name must be an IANA_SVC_NAME.

github.com/mdlayher/netlink v1.7.2/go.mod h1:xraEF7uJbxLhc5fpHL4cPe221LI2bdttWlU+ZGLfQSw=
github.com/mdlayher/socket v0.0.0-20210307095302-262dc9984e00/go.mod h1:GAFlyu4/XV68LkQKYzKhIo/WW7j3Zi0YRAz/BOoanUc=
github.com/mdlayher/socket v0.5.0 h1:ilICZmJcQz70vrWVes1MFera4jGiWNocSkykwwoy3XI=
github.com/mdlayher/socket v0.5.0/go.mod h1:WkcBFfvyG8QENs5+hfQPl1X6Jpd2yeLIYgrGFmJiJxI=