vm: support UDP port forwarding

[stek29]

Should fix #1292 and fix #1300, and maybe others

gRPC port forwarder is considered stable in lima, no need to force older SSH forwarder by default

[abiosoft]

Thanks a lot for this :)
Have you tested this and verified the behaviour?

[abiosoft]

Build failing, it looks like you didn't commit all files.

Build failing.

[stek29]

@abiosoft I have indeed forgotten to push the latest commit, sorry for that

[stek29]

Here's how I've tested it originally:

docker run --rm --name socat9k \
  --entrypoint sh \
  -p 9999:9999/tcp \
  -p 9999:9999/udp \
  alpine/socat \
  -c 'socat -u -v TCP-LISTEN:9999,fork STDOUT & socat -u -v UDP-RECV:9999 STDOUT & wait'

and in another terminal tab:

$ echo hi | nc -u localhost 9999
^C
$ echo hi | nc localhost 9999

[stek29]

I've also tested it with an actual UDP server, and looks like there are issues with udp forwarding, unfortunately.

docker run --rm \
  -p 5053:53/udp -p 5053:53/tcp \
  coredns/coredns:latest

and then:

dig @127.0.0.1 -p 5053 example.com
dig +tcp @127.0.0.1 -p 5053 example.com

udp only works exactly once, after that responses aren't delivered correctly.

I can still see the requests:

[INFO] 172.17.0.1:49232 - 33323 "A IN example.com. udp 40 false 4096" NOERROR qr,aa,rd 91 0.000146837s

but the responses never arrive (I can see the response packets on colima vm with tcpdump though, up to response from docker-proxy to the lima guestagent)

I guess lima udp forwarding isn't really working yet, I'll look further into this and report to lima upstream.

[stek29]

I've submitted a fix to upstream for lima udp forwarding being broken, I guess merging this doesn't make sense before lima issue is fixed: lima-vm/lima#3724

[abiosoft]

Thanks for your efforts.
I will wait for the upstream PR to get merged.

[stek29]

@abiosoft upstream PR has been merged, and is selected for cherry-picking into 1.2.1 release of lima

lima-vm/lima#3743

[abiosoft]

Thanks :)