From: David Miller <davem@davemloft.net>
To: Jason@zx2c4.com
Cc: netdev@vger.kernel.org, wireguard@lists.zx2c4.com,
linux-kernel@vger.kernel.org, linux-mips@linux-mips.org
Subject: Re: Misalignment, MIPS, and ip_hdr(skb)->version
Date: Thu, 08 Dec 2016 18:14:53 -0500 (EST) [thread overview]
Message-ID: <20161208.181453.1681964885150767592.davem@davemloft.net> (raw)
In-Reply-To: <CAHmME9qGoPGEFyqe0jBaZD5R51wHTEgAYb9edj+nu9nNPWSYCA@mail.gmail.com>
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Thu, 8 Dec 2016 23:20:04 +0100
> Hi David,
>
> On Thu, Dec 8, 2016 at 1:37 AM, David Miller <davem@davemloft.net> wrote:
>> You really have to land the IP header on a proper 4 byte boundary.
>>
>> I would suggest pushing 3 dummy garbage bytes of padding at the front
>> or the end of your header.
>
> Are you sure 3 bytes to get 4 byte alignment is really the best? I was
> thinking that adding 1 byte to get 2 byte alignment might be better,
> since it would then ensure that the subsequent TCP header winds up
> being 4 byte aligned. Or is this in fact not the desired trade off,
> and so I should stick with the 3 bytes you suggested?
If the IP header is 4 byte aligned, the TCP header will be as well.
next prev parent reply other threads:[~2016-12-08 23:09 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-07 18:35 Jason A. Donenfeld
2016-12-07 18:47 ` Dave Taht
2016-12-07 18:51 ` David Miller
2016-12-07 18:54 ` Jason A. Donenfeld
2016-12-07 19:52 ` David Miller
2016-12-08 0:29 ` Jason A. Donenfeld
2016-12-08 0:37 ` David Miller
2016-12-08 22:20 ` Jason A. Donenfeld
2016-12-08 23:14 ` David Miller [this message]
2016-12-11 8:07 ` Willy Tarreau
2016-12-11 10:47 ` Måns Rullgård
2016-12-10 12:25 ` Felix Fietkau
2016-12-10 13:25 ` Måns Rullgård
2016-12-10 20:09 ` Felix Fietkau
2016-12-10 20:32 ` Måns Rullgård
2016-12-10 20:36 ` Felix Fietkau
2016-12-12 16:19 ` David Laight
2016-12-12 16:31 ` Måns Rullgård
2016-12-08 0:30 ` Hannes Frederic Sowa
2016-12-08 4:34 ` Daniel Kahn Gillmor
2016-12-09 11:26 ` Jiri Benc
2016-12-10 22:18 ` Dan Lüdtke
2016-12-11 7:15 ` Greg KH
2016-12-11 14:50 ` Jason A. Donenfeld
2016-12-11 15:30 ` Andrew Lunn
2016-12-11 15:37 ` Jason A. Donenfeld
2016-12-11 16:44 ` Willy Tarreau
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