linux-kernel - tcp_recvmsg question

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Date:	Sun, 12 Sep 2010 03:11:09 -0400
From:	Mihail Ionescu <bucalelinux@...il.com>
To:	linux-kernel@...r.kernel.org
Subject: tcp_recvmsg question

Hi,

I am working on a research project, where I try to intercept the
incoming tcp packets going to a specific process. I use the 2.6.24.5
kernel version.

I tried to find out how the data is copied to the user level pointer
in the tcp_recvmsg function, but I could not find anything. I disabled
CONFIG_NET_DMA. I was assuming that, before the function finishes, the
data to be transferred to the user space is located at
msg->msg_iov->iov_base. I tried to copy this data to a kernel buffer
using copy_from_user, just before the tcp_recvmsg finishes, but the
data copied is not the same as the one which gets to the user
application. Any ideas how to get the data that is sent to the user at
this level?

Thanks,

Mihail
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