From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: Roman Mamedov <rm@romanrm.net>
Cc: Luis Ressel <aranea@aixah.de>,
WireGuard mailing list <wireguard@lists.zx2c4.com>,
Roman Mamedov <rm.wg@romanrm.net>
Subject: Re: Mixed MTU hosts on a network
Date: Sat, 14 Apr 2018 16:15:07 +0200 [thread overview]
Message-ID: <CAHmME9rHTu1dQi+xyyRnkKxVkC9bx91V06-qF513SsVt8e7FKg@mail.gmail.com> (raw)
In-Reply-To: <20180414184018.0166bc48@natsu>
Hi Roman,
I answered this in my first email to you, which perhaps got lost in
the mix of emails, so I'll quote the relevant part:
> 2) When we pad the packet payload. In this case, we pad it to the
> nearest multiple of 16, but we don't let it exceed the device MTU.
> This is skb_padding in send.c. This behavior seems like the bug in
> your particular case, since what matters here is the route's MTU, not
> the device MTU. For full 1412 size packets, the payload is presumably
> being padded to 1424, since that's still less than the device MTU. In
> order to test this theory, try setting your route MTU, as you've
> described in your first email, to 1408 (which is a multiple of 16). If
> this works, let me know, as it will be good motivation for fixing
> skb_padding. If not, then it means there's a problem elsewhere to
> investigate too.
In short, because 1408 is a multiple of 16 so it didn't get rounded
up, whereas 1412 got rounded up to 1424.
Jason
next prev parent reply other threads:[~2018-04-14 14:00 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-16 9:25 Roman Mamedov
2018-03-16 9:35 ` Matthias Ordner
2018-03-16 10:53 ` Roman Mamedov
2018-03-16 16:20 ` Roman Mamedov
2018-03-16 10:01 ` Kalin KOZHUHAROV
2018-03-26 19:12 ` Luis Ressel
2018-04-14 1:38 ` Jason A. Donenfeld
2018-04-14 2:40 ` Jason A. Donenfeld
2018-04-14 13:16 ` Jason A. Donenfeld
2018-04-14 13:40 ` Roman Mamedov
2018-04-14 14:15 ` Jason A. Donenfeld [this message]
2018-04-14 14:38 ` Roman Mamedov
2018-04-14 14:45 ` Jason A. Donenfeld
2018-04-14 15:20 ` Roman Mamedov
2018-04-14 23:08 ` Jason A. Donenfeld
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAHmME9rHTu1dQi+xyyRnkKxVkC9bx91V06-qF513SsVt8e7FKg@mail.gmail.com \
--to=jason@zx2c4.com \
--cc=aranea@aixah.de \
--cc=rm.wg@romanrm.net \
--cc=rm@romanrm.net \
--cc=wireguard@lists.zx2c4.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).