Share memory between Kernel and user

gomathisankar · 05-23-2007, 05:56 AM

Hi

I want to make a common memory space between user and Kernel. I need to send each packet to a particular place from my network driver to a memory. And One of the application will take that and will do some process.Is there any way to share a common space between user and kernel. Thanks in advance for your help

Thanks & Regards
Gomathisankar.P

Mara · 05-24-2007, 03:53 PM

You should do this using one of the standard mechanisms. Iptables module is one solution, you can also think about extra /proc or /dev file by your driver, depending on what you want to do with the packet after it is processed.

asprakash · 05-25-2007, 01:46 AM

My suggestion is, using shared memory you can do this. Cretae an shared memory device in /dev, send ur data from ur driver to that share memory. Ur Application can access those spaces as a device, like "/dev/shm".

gomathisankar · 05-25-2007, 07:17 AM

Hi

Thanks for your reply. Can you guide me how to do that.

Thanks & regards
Gomathisankar.P

asprakash · 05-26-2007, 05:59 AM

Sure. I have implemented this concept in RTLinux and Linux.

What type of help you want.

The ceoncept is simple,Create a shared memory device from kernel. Write your data here.Read the same data by application program.

Any other info you need.

gomathisankar · 05-28-2007, 01:33 AM

Thank you very much Prakash.I understood your thought.But how to access the device from the Kernel(i mean to say from my driver). From the application you can access using open the dev,read and write . But how it is possible from the driver .

Thanks & Regards

Gomathisankar.P

asprakash · 05-29-2007, 01:16 AM

Then my logic is not suitable for you.I used IPC to shared the data b/w the processes.Ur case is diffi. You just ignore the above and go to the following link.Hope it will helpful for you.
I dont have more idea abt it, but APMK, we can share the data from kernel to user land by the following ways, relayfs, procfs, debugfs, ioctls, mmap....

http://www.linuxjournal.com/article/1287
http://www.linuxjournal.com/article/1312

gomathisankar · 05-31-2007, 01:55 AM

Hi

Seems netlink is a good technique ofr these kind of application.But i am not able to find any Good working program in Linux kernle 2.6 . Anybodies please help me
Thanks & regards
Gomathisankar