[ovs-dev] How dpif-linux query the flow table, and where it maintain the flow table?

LIU Binghan binghanluc at gmail.com
Sat Apr 7 11:19:35 PDT 2012

No, No, No.  I think you did not get my point.     

My question is how user space(the controller) processes the packets that kernel space does not know? Is there any tables in user space?

On 2012-4-7, at 下午7:46, Ben Pfaff wrote:

> On Sat, Apr 07, 2012 at 02:12:40PM +0200, LIU Binghan wrote:
>> My idea is, in the beginning,' datapath' does not have any flow
>> table. If it found a flow that it does not know, then it would pass
>> the flow key and packet through netlink to 'dpif'. 'dpif' processes
>> the packet, and also tells the datapath through netlink to expand its
>> flow table about this flow. After that, packets would process by
>> kernel.
> Yes, this is correct.
>> Thus, I think datapath need to learn the flow information(flow key
>> associate with actions) from dpif.
> Yes.
>> But, right now, as my understanding about what you say, there should
>> be some flowtable in the kernel(not datapath kernel module).
> I don't understand this distinction.  What is the difference between a
> flow table in the kernel and a flow table in the datapath kernel module?
>> I asked this kind of questions is because I want to develop a new
>> tunnel protocol for openvswitch. Therefore, i want to know how user
>> space maintains the flow table, I lost in this part.
> Good luck!

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