Porting to macOS

Porting to macOS

[DUO Labs]

I started doing some preliminary work on porting passt to macOS (I would have responded to issue 6 directly, but I can't seem to make an account); however, I wanted to know how exactly the system works --- does it _require_ a tap device, or can I safely remove that file from the compilation target (I know that pasta requires it, though)?

Re: Porting to macOS

[Stefano Brivio]

Hi,

On Tue, 10 Sep 2024 16:15:33 -0400
DUO Labs <dvdugo333@gmail.com> wrote:

> I started doing some preliminary work on porting passt to macOS

That's great to hear!

> (I would have responded to issue 6 directly, but I can't seem to make an
> account);

Sorry for that, you should have your request confirmation email now.

I'm reviewing those manually as we have botnets sending automated
account requests for seemingly no benefit, so they might be a bit
delayed from time to time.

> however, I wanted to know how exactly the system works ---
> does it _require_ a tap device, or can I safely remove that file from
> the compilation target (I know that pasta requires it, though)?

passt itself doesn't need a tap device, but note that tap.c is a bit of
a misnomer: it refers to anything guest/container side (be it a UNIX
domain socket, a pre-opened file, or an actual tuntap network
interface).

I guess a reasonable way forward would be to conditionally disable
pasta-related functions, in tap.c and elsewhere, for non-Linux targets
(perhaps easier: conditionally enable them for Linux?).

That is, you won't need tap_handler_pasta() and friends, but you'll need
tap_handler_passt().

-- 
Stefano

Re: Porting to macOS

[DUO Labs]

Question: In icmp.c:110, the line reads `ih6->icmp6_identifier = htons(ini->eport);`, where `ih6` is of type icmp6hdr *. However, this field does not exist --- ih6->u_echo.icmp6_identifier does. Is this intended?

Re: Porting to macOS

[DUO Labs]

Oh, never mind --- forgot to copy over the entire header, which includes the #defines.

Re: Porting to macOS

[DUO Labs]

Is AF_NETLINK required for passt usage, or is it only for pasta?

Re: Porting to macOS

[Stefano Brivio]

On Wed, 11 Sep 2024 22:19:15 -0400
DUO Labs <dvdugo333@gmail.com> wrote:

> Looking at the archives, it looks like my message was never received (I'm
> still figuring this mailing list stuff out). I'm pasting my message below:

Non-subscribers' posts are held to avoid spam, I have to approve them
manually. You can register to the list to avoid delays:

  https://lists.passt.top/postorius/lists/passt-dev.passt.top/

> Is AF_NETLINK required for passt usage, or is it only for pasta?

It's more heavily needed for pasta because, there, we use it to
directly configure the networking in the container (with --config-net),
whereas with passt the configuration happens via DHCP/NDP/DHCPv6.

With passt, we use netlink just to source addresses and routes from the
host. I see two alternatives for Darwin:

- use sysctls with NET_RT_DUMP / NET_RT_IFLIST2 / NET_RT_DUMP2 to fetch
  the same information. It's not clear to me if it needs root, though,
  or if there's a different way to fetch information without root

- force the user to give a manual configuration (with options -a, -g at
  least)

-- 
Stefano