Re: IOVisor help

Ashhad Sheikh <ashhadsheikh394@...>

Hello Brenden,
Thanks for your helpful replay. These are actually interesting things you mentioned I will surely look into these. Using SOCKET was my initial idea but I want to know that are they full duplex or not?(What if user space wants to send back something)
I simple want to send traffic from data plane to user space and back to data plane after some processing. Also it will be highly appreciable if you please link me any example related to SOCKETS.


On Wed, Sep 23, 2015 at 10:00 AM Brenden Blanco <bblanco@...> wrote:
Hello Ashhad,

It would be good to know what type of use case you have in mind for transferring data between user and kernel space, then perhaps I can answer more accurately.

For instance, if using the KPROBE program type, it is possible to use a BPF program as a filter of events that are later accessible through mmap, see "MMAP layout" in

Or, if using a SOCKET type, the BPF program works as it does traditionally with tcpdump, to filter packets into a socket. A userspace program can listen on said socket.

For the SCHED_ACT and SCHED_CLS types, the BPF program can use a helper function to clone or redirect a packet to an ifindex of its choosing.

Please let me know which of these categories you are interested in.

Brenden Blanco

On Tue, Sep 22, 2015 at 4:57 AM, Ashhad Sheikh via iovisor-dev <iovisor-dev@...> wrote:
Hello, I am Ashhad. A CS major undergraduate student. I am researching on iOVISOR, specifically on it's real life performance.

I want to ask that Is it possible to have netlink communication between eBPF code and userspace --- if so how? I want to see if user space programs can communicate with eBPF beyond polling shared maps or not.
Waiting for a helpful response


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