From: Eric Dumazet <eric.dumazet@gmail.com>
To: Jerry Yu <jerryy@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Protocol handler using dev_add_pack
Date: Wed, 11 Jul 2012 16:17:19 +0200 [thread overview]
Message-ID: <1342016239.3265.8007.camel@edumazet-glaptop> (raw)
In-Reply-To: <CAP2AAQMvx5yxVRLN4AT_YdsFJAUDRgSNwzq0A3x8JyZgXKEjmw@mail.gmail.com>
On Wed, 2012-07-11 at 10:38 -0300, Jerry Yu wrote:
> I am working on a kernel module to monitor all TCP packets. I created a protocol
> handler with protocol code ETH_P_ALL to handle all incoming and outgoing
> TCP packets. The code worked fine on 2.6.14 kernel, but in current 3.2.0-26
> kernel, I am no longer able to get the TCP payload for outgoing packets.
> The data in TCP payload section of skb->data are mainly 0x00. I am still
> able to get incoming TCP packets' payloads though.
>
> Is there any change in 3.2.0 or other early kernel versions that will cause
> this issue?
Maybe you make wrong assumptions in your code.
skb->data doesnt exactly contains tcp payload of locally generated TCP
packets, unless you disabled scatter-gather on the NIC
ehtool -K eth0 sg off
next prev parent reply other threads:[~2012-07-11 14:17 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-11 13:38 Protocol handler using dev_add_pack Jerry Yu
2012-07-11 14:17 ` Eric Dumazet [this message]
2012-07-12 18:05 ` Jerry Yu
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