Re: Tips for local testing guestfwd

[Lukas Straub]

CC'ing SLIRP and net maintainer.

On Sun, 25 Jun 2023 22:58:36 -0700
Felix Wu <flwu@google.com> wrote:

> Hi all,
> 
> TL,DR: I am working on QEMU ipv6 guestfwd feature and finished coding, and
> would like to learn the best practice to test it.
> Context: in slirp side this task is tracking by [1].
> Currently, I have done following:
> i. made char parse + guestfwd functions happy with ipv6 address.
> ii. enabled debug print and made sure the ip and port are inserted into the
> forward list in libslirp.
> To sufficiently verify it's working, I do have three questions:
> 1. I want to forward a port in the guest (OS in QEMU) to a port 22 on the
> host OS, and ssh from guest back to host,
> does this sound reasonable? If this is not a good idea, what method is
> recommended?
> 2. I want to understand what ip I should use. Currently I have following
> formats for the QEMU invocation in ipv6:
> ```
> guestfwd=tcp:[::1]:1234-tcp:[my:host:ip:from:ifconfig]:22
> ```
> I know the general form is `guestfwd=tcp:server:port-dev`, where
> server:port is for guest, dev is for host.
> Adding [] in my implementation will let QEMU know it's ipv6.
> Is the aforementioned invocation correct? Or in this case [::1] is the
> local host address and I should put qemu address
> for it instead?
> 3. Is there a default ipv6 address for QEMU instance? I think I need it in
> the invocation.
> 
> Thanks in advance! Felix
> 
> [1]. https://gitlab.freedesktop.org/slirp/libslirp/-/issues/67

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