From: Kristian Evensen <kristian.evensen@gmail.com>
To: Jan Engelhardt <jengelh@medozas.de>
Cc: netfilter-devel@vger.kernel.org
Subject: Re: Wrong MAC in redirected packet
Date: Wed, 25 Mar 2009 20:56:10 +0100 [thread overview]
Message-ID: <49CA8C5A.1030908@gmail.com> (raw)
In-Reply-To: <alpine.LSU.2.00.0903252047020.28681@fbirervta.pbzchgretzou.qr>
Jan Engelhardt skrev:
> On Wednesday 2009-03-25 20:47, Kristian Evensen wrote:
>
>> However, I have noticed a similar problem when using my module on incoming
>> packets in PREROUTING (on the multihomed receiver), the IP adress is changed
>> (accoring to my dmesg-output) but then they are not heard from again.
>>
>
> Probably dropped due to L3 or L4 checksum mismatches. While we try to
> change the checksum, I have not verified it for all cases.
>
>
Hm, I am noe sure. I recalculate the checksum (using csum_replace4 for
l3 and inet....replace4 for l4) after modifying the destination IP, and
when used with OUTPUT the checksum is correct. Since tcpdump/Wireshark
outputs the packets before they are modified I haven't been able to
verify this though.
-Kristian
next prev parent reply other threads:[~2009-03-25 19:52 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-25 14:27 Wrong MAC in redirected packet Kristian Evensen
2009-03-25 14:33 ` Jan Engelhardt
2009-03-25 15:00 ` Kristian Evensen
2009-03-25 15:04 ` Jan Engelhardt
2009-03-25 15:17 ` Kristian Evensen
2009-03-25 15:20 ` Jan Engelhardt
2009-03-25 19:47 ` Kristian Evensen
2009-03-25 19:48 ` Jan Engelhardt
2009-03-25 19:56 ` Kristian Evensen [this message]
2009-03-25 19:57 ` Jan Engelhardt
2009-03-25 21:00 ` Kristian Evensen
2009-03-26 10:26 ` Kristian Evensen
2009-03-26 20:07 ` Jan Engelhardt
2009-03-26 20:54 ` Kristian Evensen
2009-04-26 9:46 ` Jan Engelhardt
2009-04-26 16:22 ` Kristian Evensen
2009-04-26 21:29 ` Jan Engelhardt
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=49CA8C5A.1030908@gmail.com \
--to=kristian.evensen@gmail.com \
--cc=jengelh@medozas.de \
--cc=netfilter-devel@vger.kernel.org \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.