From: Stefano Brivio <sbrivio@redhat.com>
To: Jon Maloy <jmaloy@redhat.com>
Cc: passt-dev@passt.top, lvivier@redhat.com, dgibson@redhat.com
Subject: Re: [PATCH v2] tap: always set the no_frag flag in IPv4 headers
Date: Thu, 20 Feb 2025 17:27:35 +0100 [thread overview]
Message-ID: <20250220172735.757f05a7@elisabeth> (raw)
In-Reply-To: <20250219152041.2257268-1-jmaloy@redhat.com>
On Wed, 19 Feb 2025 10:20:41 -0500
Jon Maloy <jmaloy@redhat.com> wrote:
> When studying the Linux source code and Wireshark dumps it seems like
> the no_frag flag in the IPv4 header is always set. Following discussions
> in the Internet on this subject indicates that modern routers never
> fragment packets, and that it isn't even supported in many cases.
>
> Adding to this that incoming messages forwarded on the tap interface
> never even pass through a router it seems safe to always set this flag.
>
> This makes the IPv4 headers of forwarded messages identical to those
> sent by the external sockets, something we must consider desirable.
>
> Signed-off-by: Jon Maloy <jmaloy@redhat.com>
> ---
> v2: Updated checksum algorithm to consider the change
Applied.
--
Stefano
prev parent reply other threads:[~2025-02-20 16:27 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-19 15:20 [PATCH v2] tap: always set the no_frag flag in IPv4 headers Jon Maloy
2025-02-20 16:27 ` Stefano Brivio [this message]
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=20250220172735.757f05a7@elisabeth \
--to=sbrivio@redhat.com \
--cc=dgibson@redhat.com \
--cc=jmaloy@redhat.com \
--cc=lvivier@redhat.com \
--cc=passt-dev@passt.top \
/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.
Code repositories for project(s) associated with this public inbox
https://passt.top/passt
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 IMAP folder(s).