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From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Miller <davem@davemloft.net>, Netdev <netdev@vger.kernel.org>
Subject: Re: [PATCH net 3/3] wireguard: send: account for mtu=0 devices
Date: Fri, 14 Feb 2020 16:56:22 +0100	[thread overview]
Message-ID: <CAHmME9qErQbU5Y36i=3L_R_PYw2Li_Vv2a9k7bSuMxpuLMcgsg@mail.gmail.com> (raw)
In-Reply-To: <ba6b4c66-3c15-cdbc-7d0e-eaf307c5904c@gmail.com>

On Fri, Feb 14, 2020 at 4:18 PM Eric Dumazet <eric.dumazet@gmail.com> wrote:
> > However, while min_mtu=0 seems fine, it makes sense to restrict the
> > max_mtu. This commit also restricts the maximum MTU to the greatest
> > number for which rounding up to the padding multiple won't overflow a
> > signed integer. Packets this large were always rejected anyway
> > eventually, due to checks deeper in, but it seems more sound not to even
> > let the administrator configure something that won't work anyway.
> >
> If mtu is set to 0, the device must not send any payload.

Yes, but there's still internal keepalive messages.

>
> Are you sure this works ?
>
> Last statement :
>
> return padded_size - last_unit;
>
> will return a a ' negative number'

Woah nelly I don't know how I missed this. Thanks! Will send a v2 of
this patchset.

      reply	other threads:[~2020-02-14 18:00 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-14 13:34 [PATCH net 0/3] wireguard fixes for 5.6-rc2 Jason A. Donenfeld
2020-02-14 13:34 ` [PATCH net 1/3] wireguard: selftests: reduce complexity and fix make races Jason A. Donenfeld
2020-02-14 13:34 ` [PATCH net 2/3] wireguard: receive: reset last_under_load to zero Jason A. Donenfeld
2020-02-14 13:34 ` [PATCH net 3/3] wireguard: send: account for mtu=0 devices Jason A. Donenfeld
2020-02-14 15:18   ` Eric Dumazet
2020-02-14 15:56     ` Jason A. Donenfeld [this message]

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