Re: [Fwd: Re: upcall sample patch]

From: Steve French
Date: Thu Dec 07 2006 - 14:08:35 EST


Steve French wrote:
For the CIFS Kerberos/SPNEGO case the Kerberos ticket can end up almost 64K in size and need to be passed down by Samba userspace helpers to kernel (for sending over the kernel socket to the server in the data area of the smb that the kernel cifs code formats).

Is the limit on the Linux kernel connector really 1K for passing down to kernel?

On Wed, 2006-12-06 at 17:55 -0600, Steve French wrote:
simo wrote:
Steve,
I am experimenting using netlink.

I could v. easily send messages from user space to the kernel module,
adapting the provided examples. I am finding some difficulty in
understanding how the other way around is supposed to work though.

However while digging into headers, I found that currently the maximum
message size is set to 1024 bytes. That's a bit annoying.


Linux kernel connector is the preferred netlink wrapper and it has
sample programs that I found.
Not sure the maximum size

Steve I looked into the sample programs in 2.6.19, cn_test.c and ucon.c
are provided. Unfortunately it is not clear from them how to make
upcalls. It is very easy to make downcalls, but I found it hard to find
out what's the right way to catch messages sent from the kernel in the
user space. Do you have nay other examples?

For the limit, just look in linux/connector.h there you can find a
define that sets the MAX LEN of the message to 1024.

Simo.
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