Support port mapping

[feiskyer]

CNI doesn't do port-mapping today. We could support port mapping via iptables.

[heartlock]

we can use portmapping-manager to do port mapping via iptables like https://github.com/kubernetes/kubernetes/blob/master/pkg/kubelet/network/kubenet/kubenet_linux.go. What do you think? @feiskyer

[feiskyer]

@heartlock A standard CNI plugin is more preferred, e.g. containernetworking/plugins#1, which is also depending on kubernetes/kubernetes#42202.

[heartlock]

Cool! I will follow containernetworking/plugins#1

[heartlock]

Good news! containernetworking/plugins#1 was merged. I will start to work on supporting port mapping.

[feiskyer]

@heartlock We need to support cni plugin chaining first. Would you like to file a PR for this first?

Refer kubernetes/kubernetes#42202.

[heartlock]

@feiskyer Sure, will do it.