Create test suite that works with userspace networking.

[alfreb]

Several tests will work with slirp, but not the UDP test as it stands, because it has an IPv6 part, and there doesn't seem to be a way to forward ports to IPv6 addresses with slirp. For example, hostfwd=udp::4242-:4242 forwards traffic to IPv4 addresses, has no effect on IPv6. See more details here: includeos/vmrunner#31

Ideally we'd find a way to run all the current networking tests with userspace networking, but if not, a subset would be a great start. The value of this would be that we would not require any sudo setup before running a reasonable test suite. If this would let us run tests in e.g. github actions, that's a great benefit. If we still have to maintain our own CI servers, maybe less important, but still nice to not require sudo.

A third alternative is to use the IncludeOS userspace mode to run tests. This will be a great way to test the IP stack against itself, but it won't stress tests the x86 hardware platform, which is hard to get right. So I don't see userspace tests ever displacing tests running in an actual VM (emulated or not).

Acceptance criteria:

• At least TCP, UDP is tested over IPv4
• Some aspects of IPv6 is tested
• No sudo is required either for setup or running of the tests.
• QUICK_SMOKE=1 ./test.sh will run only network tests that pass in usermode.

[MagnusS]

Perhaps some of the tests could be updated to run with -netdev socket and python scapy: https://john-millikin.com/improved-unix-socket-networking-in-qemu-7.2

[fwsGonzo]

This is my userspace networking implementation that I used to, among other things, fuzz the network stack with:

https://github.com/fwsGonzo/userspace

It should have a TAP driver for IncludeOS. I don't remember the details.