From: Krzysztof Oledzki <olel@ans.pl>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: netdev@vger.kernel.org
Subject: Re: incorrect cksum with tcp/udp on lo with 2.6.20/2.6.21/2.6.22
Date: Tue, 2 Oct 2007 16:15:15 +0200 (CEST) [thread overview]
Message-ID: <Pine.LNX.4.64.0710021606550.3175@bizon.gios.gov.pl> (raw)
In-Reply-To: <20071002104033.GA30281@gondor.apana.org.au>
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On Tue, 2 Oct 2007, Herbert Xu wrote:
> On Mon, Sep 24, 2007 at 11:44:19AM +0200, Krzysztof Oledzki wrote:
>>
>> So, with DR mode, packet goes by the lo device (with bad checksum) and
>> then get redirected outside. Unfortunately, when it leaves host it has bad
>> checksum, too. :(
>
> Did you check this by taking a tcpdump on an external host?
Yes.
> Doing a local tcpdump doesn't work as tcpdump won't show the
> correct checksum if checksum offload is enabled.
Indeed, I'm aware about this.
> If it's really sending a bogus checksum then it's a bug in
> LVS.
I'm not sure if we should call it a bug. LVS does not support such
configuration by default - it requires kernel patching. However, it worked
with older kernels so that's why I asked if it is possible to force full
TCP/UDP checksum calculation?
Thank you.
Best regards,
Krzysztof Olędzki
next prev parent reply other threads:[~2007-10-02 14:15 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-13 17:55 incorrect cksum with tcp/udp on lo with 2.6.20/2.6.21/2.6.22 Krzysztof Oledzki
2007-09-23 4:39 ` Herbert Xu
2007-09-23 21:18 ` Krzysztof Oledzki
2007-09-24 1:30 ` Herbert Xu
2007-09-24 9:44 ` Krzysztof Oledzki
2007-10-02 10:40 ` Herbert Xu
2007-10-02 14:15 ` Krzysztof Oledzki [this message]
2007-10-02 14:17 ` Herbert Xu
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