Development discussion of WireGuard
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From: Daniel Lenski <dlenski@gmail.com>
To: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: David Woodhouse <dwmw2@infradead.org>,
	WireGuard mailing list <wireguard@lists.zx2c4.com>
Subject: Re: Duplicate IP address, and permissions problems on Windows
Date: Wed, 7 Apr 2021 16:00:46 -0700	[thread overview]
Message-ID: <CAOw_LSEasJuHDPXGkVQnYh_aHd+nOY53D0LRUXuH+pN45ynz2w@mail.gmail.com> (raw)
In-Reply-To: <CAHmME9q-qw=sCxz6Fije+ENQTY2-GdS4bZLSakuh+6Eze4LR3w@mail.gmail.com>

On Tue, Apr 6, 2021 at 5:17 PM Jason A. Donenfeld <Jason@zx2c4.com> wrote:
> It's pretty typical behavior on Windows for IP addresses to be
> exclusive per interface. WireGuard for Windows does something similar:
> https://git.zx2c4.com/wireguard-windows/tree/tunnel/addressconfig.go#n22

Thank you! That's very interesting.

Following David's initial implementation, I wrote something for
OpenConnect that's pretty much the same as yours:
https://gitlab.com/openconnect/openconnect/-/compare/5e6e9b850756157164f83cd4fedafb747fbbd50f...0bca5b32ac478b5d03b6e88f96bf29c6556610a5

1. Uses GetAdaptersAddresses to list all the addresses
2. If/when it finds a clashing address, it uses
GetUnicastIpAddressTable to determine the up/down state of the other
interface
3. Only delete the address from the other interface if it's non-UP.

I was also annoyed that the GetAdaptersAddresses return structure
doesn't provide the adapter state, and that I had to go for this
convoluted O(n^2) design.

I guess this reassures me that there isn't an obviously-better way to do it.

Dan

  parent reply	other threads:[~2021-04-10 14:30 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-06 11:29 David Woodhouse
2021-04-07  0:17 ` Jason A. Donenfeld
2021-04-07  8:18   ` David Woodhouse
2021-04-07 23:05     ` Daniel Lenski
2021-04-12 17:50       ` Jason A. Donenfeld
2021-04-07 23:00   ` Daniel Lenski [this message]
2021-04-08  8:46     ` David Woodhouse
2021-04-08 16:09       ` Daniel Lenski
2021-04-08 16:59     ` David Woodhouse
2021-04-08 17:53       ` Daniel Lenski
2021-04-10  9:25         ` David Woodhouse

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