Very Computer

Hi all,

I have a kernel module that receive IP datagram, using netfilter that
pass the datagram to my module.
The kernel module execute some operation and I have the necessity to
pass the results (a string of char essentially) to an application
(user-mode).
How I can make? There is someone that has an example of such type of
passage of data?

I have realized the contrary passage (from user-mode to kernel)
registering a sys_call to a function that is implementes in my kernel
module.
There are other mechanisms that make both passages?

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Quote:> Hi all,

> I have a kernel module that receive IP datagram, using netfilter that
> pass the datagram to my module.
> The kernel module execute some operation and I have the necessity to
> pass the results (a string of char essentially) to an application
> (user-mode).

Try looking at the raw driver, which implements a zero copy device
which you can use to pass data to user mode.

- --
burton samograd

http://kruhftwerk.dydns.org
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The usual paradyme for kernel-to-user space data movement is the user-space
initiated open(2) / read(2) sequence.

Quote:> I have realized the contrary passage (from user-mode to kernel)
> registering a sys_call to a function that is implementes in my kernel
> module.

Why? Isn't open(2) / write(2) good enough?

Quote:> There are other mechanisms that make both passages?

Yes. open(2) / read(2) / write(2) / close(2)

--
Lew Pitcher

Master Codewright and JOAT-in-training
Registered (Slackware) Linux User #112576 (http://counter.li.org/)

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Quote:>> I have realized the contrary passage (from user-mode to kernel)
>> registering a sys_call to a function that is implementes in my kernel
>> module.

> Why? Isn't open(2) / write(2) good enough?

Maybe he wants zero copy data transfer.

- --
burton samograd

http://kruhftwerk.dydns.org
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