Re: Accessing Skbuff in RTLinux

> Hi,
> 
> I am a student and newbie to RTLinux and I am using
> free version of RTLinux.
> 
> I am using linux kernel 2.4.20 for a small networking
> project. I divert the linux network packets from
> netfilter post route hooks to my kernel module and add
> my own ethernet addresses in the eth header and sends
> the packet out by calling dev_queue_xmit() at a
> precise time interval .
> 
> Now I want to achieve the same with RTLinux. 
> 
> My questions are
> 1) Can I access skbuff pointer in Linux kernel module
> and as well as RTLinux process at the same time? If
> yes how to achieve the synchronization between these
> two? If not, can it be achieved by calling alloc_skb()
> in RTLinux process and copying the original buffer
> through FIFOs?
> 
> 2) How can we achieve synchronization between my linux
> kernel module and my RTLinux module?
> 
> 3) Can I access ethernet driver functions (like
> dev_queue_xmit) from RTLinux module?
> 
> 4) I have a softIRQ in my linux kernel module. Does it
> work seemly with RTLinux module?
> 
you can't really do that deterministically even if you call the xmit 
function in some deterministic way as you can't enforce reliable allocation
for the packet related data structs - so you might want to use REDD if you
need deterministic communication or RTSock if you just want RT-safe access
to non-RT Linux networking facilities.

So depending on the other end of the wire -
if receiving side is RT -> REDD
if receiving side is non-RT -> RTSock

hofrat
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