platform/qemu: Enable forwarding multiple ports

[mike-nguyen]

One of the limitations of unprivileged qemu is there is no
machine to machine networking. Host port forwarding allows the
host machine to communicate to the guest machine through the local
host address. It also allows the guest machine to communicate
with the host machine through the gateway address. With two
guest machines, we can bridge the two guests through the host
machine with port forwarding. For example, Host A can run a
webserver on port 8080 and Host B can access Host A's webserver
through its gateway (host machine) address http://10.0.2.2:8080.

This is useful for creating test services (such as tang) for use
by the test machine.

This is a prep PR for Tang/SSS tests.

[darkmuggle]

While I was looking at the code the other day, I wondered about doing this; well done for tackling it.

One request though: could you add a basic test? We have a problem with this code changing quickly and having a test would ensure to protect it.

Otherwise, LGTM

[openshift-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: darkmuggle, mike-nguyen

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Details

Needs approval from an approver in each of these files:

• OWNERS [darkmuggle,mike-nguyen]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[mike-nguyen]

While I was looking at the code the other day, I wondered about doing this; well done for tackling it.

One request though: could you add a basic test? We have a problem with this code changing quickly and having a test would ensure to protect it.

Otherwise, LGTM

#1407 has a tests included

[mike-nguyen]

Closing in favor of #1407 with the test