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From: David Woodhouse <dwmw2@infradead.org>
To: Simon Rozman <simon@rozman.si>,Daniel Lenski <dlenski@gmail.com>
Cc: WireGuard mailing list <wireguard@lists.zx2c4.com>
Subject: RE: Allowing space for packet headers in Wintun Tx/Rx
Date: Mon, 12 Apr 2021 14:00:21 +0100	[thread overview]
Message-ID: <38E774FD-16C8-4788-8C31-634A7AA4248A@infradead.org> (raw)
In-Reply-To: <9940aef2c1064fc785b51ac860020a18@rozman.si>



On 12 April 2021 12:38:30 BST, Simon Rozman <simon@rozman.si> wrote:
>> > We'll also need to be able to WintunAllocateSendPacket() of the
>full
>> > possible MTU, then receive and decrypt into that, and send only the
>> > actual size of the packet we received.
>
>How about this:
>https://git.zx2c4.com/wintun/commit/?id=03b6cd410c8963d1888966edf31fdc35a4c8b523
>
>Should be backward compatible. Tested with the existing stable
>wireguard-windows release 0.3.10.

Looks good; thanks. However...

>> 2) Some VPN protocols concatenate multiple packets into a single
>> aggregate on the wire. On Linux we can decrypt, truncate, and send to
>> the tunnel interface without further copying.
>> 
>> Case (1) can be handled with overallocate-and-shrink. Case (2) is
>pretty
>> rare among the protocols that OpenConnect supports, so fallback to
>> memcpy seems fine.

Case (2) is fairly easy to handle when the L3 packet size doesn't use up the whole TUN_PACKET size, isn't it? We can loop and consume multiple smaller packets?

-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.

  reply	other threads:[~2021-04-12 13:00 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-07 11:49 Allowing space for packet headers in Wintun Tx/Rx David Woodhouse
2021-04-07 23:15 ` Daniel Lenski
2021-04-08 14:37   ` David Woodhouse
2021-04-08 16:42     ` Daniel Lenski
2021-04-08 17:10       ` David Woodhouse
2021-04-08 17:37         ` Daniel Lenski
2021-04-10 13:38         ` Simon Rozman
2021-04-10 14:35           ` David Woodhouse
2021-04-10 18:32             ` Daniel Lenski
2021-04-12 11:38               ` Simon Rozman
2021-04-12 13:00                 ` David Woodhouse [this message]
2021-04-12 17:03                   ` Jason A. Donenfeld
2021-04-13 22:09                     ` Jason A. Donenfeld

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