[ANNOUNCE] Wintun 0.9 Released with Major Usability Improvements

Guy Godfroy guy.godfroy at gugod.fr
Thu Nov 12 14:19:27 CET 2020

Just noticed that wintun icon is heavily inspired from french subway
warning message "Don't put yout hands on the door" :-)

Anyway, great job.

Le 09/11/2020 à 17:25, Jason A. Donenfeld a écrit :
> Hi folks,
> Simon and I are very excited to announce the release of Wintun 0.9, the
> release in which Wintun finally becomes easy and enjoyable to use by
> developers. I consider this the most significant release of Wintun yet.
> Webpage: https://www.wintun.net/
> For background: Wintun is a driver for the Windows kernel that enables
> userspace programs to create network tunnels. It's a "/dev/net/tun" of the
> Windows world. We use this for WireGuard. We had investigated OpenVPN's "tap6"
> driver but found it to be a crumbling mess with dubious security, and instead
> endeavored to write a lightweight minimal replacement that obtains extremely
> high speeds using a ring buffer, similar to Linux's io_uring.
> Big Change 1: API Library and Easy Distribution
> -----------------------------------------------
> We used to rely on an obscure Microsoft technology for distributing Wintun,
> called MSI Merge Modules (MSM), in which application writers would bundle the
> signed MSM we provided as part of their MSI installer. This was great in that
> it encapsulated a lot of logic and hid it from developers, but relying on MSM
> was a hassle and precluded the use of Wintun in many non-MSI apps.
> The MSM also would simply make sure the driver was installed, but wouldn't
> provide anything else. It was up to developers to then navigate arcane Windows
> driver instantiation APIs, which are some of the oldest and most obscure to
> use. Then, once installed, developers had to manage a ring and various IOCTLs
> themselves. It all worked -- WireGuard and OpenVPN (after receiving our
> assistance) successfully deployed it -- but it was cumbersome enough that
> nobody else was going to use this.
> With Wintun 0.9, we're changing what we distribute and also providing an easy
> to use API. Rather than shipping MSMs to developers, we now ship a single
> basic boring wintun.dll. This dll hides all of the driver installation and
> adapter instantiation logic, and provides a nice interface for managing
> adapters and shuffling data in and out of the ring buffer. So, application
> developers can now just grab that dll, plop it into their application like
> they would any other dll, and use Wintun without even noticing that it's
> inserting a kernel driver when necessary
> Big Change 2: Support for WOW64 and ARM
> ---------------------------------------
> Windows does not support setupapi.dll and related driver functions on 32-bit
> processes running on 64-bit operating systems. This meant that it was
> impossible for WOW64 processes to use Wintun. Wintun also formerly required
> 64bit addresses, which made the kernel ABI clumsy for WOW64 processes. With
> Wintun 0.9, we now bundle a 64-bit version of Wintun inside 32-bit versions of
> the wintun.dll, and we marshal calls back and forth to an on-demand proxy
> process running on the native architecture.
> Not only do we have this for basic WOW64, but we also have this working for
> Windows' ARM64 emulation of x86 binaries. So you can now run an x86 program on
> ARM64 and wintun.dll will figure out what to do.
> This has big effects for us. Since Go still has not been ported to ARM64, we
> use an ARM build and rely on this new feature of Wintun. This means we should
> have a WireGuard for ARM64 Windows release in the coming week or two.
> Big Change 3: Administrator User Permissions
> --------------------------------------------
> Wintun requires the Local System user. But if you're running as Administrator,
> the wintun.dll library will attempt to do its operations as Local System,
> automatically. This effectively means that normal apps can bundle Wintun now,
> rather than just services.
> Please let us know if you have any questions or feedback. We're certainly
> interested in developer reports on what integrating this is like.
> - The API reference is available online:
>   https://git.zx2c4.com/wintun/about/
> - And there's some simple example code too:
>   https://git.zx2c4.com/wintun/tree/example/example.c
> - A signed wintun.dll for amd64, arm64, x86, and arm is on the webpage:
>   https://www.wintun.net/
> - And of course, it's open source:
>   git clone https://git.zx2c4.com/wintun
> Regards,
> Jason

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