On Thu, Nov 08, 2012 at 08:08:05PM +0200, Dan Shechter wrote:
> For unrelated reasons, I can't directly receive the TCP stream.
>
> I must copy the TCP data from a running stream to another server. I
> can use tap or just port-mirroring on the switch. So I can't use any
> network stack or leverage any offloading.
>
> I also need to modify the received data, and add few application
> headers before sending it as a multicast udp stream.
>
> Winsock is userland. What I want to do is in the kernel, even before
> ip_input. I guess it should be faster.
>
> I am looking at netFPGA too, but prefer to do this in software.
>
You might want to try this:
http://info.iet.unipi.it/~luigi/netmap/
It's FreeBSD and Linux only, though.
The emerging solution for high performance traffic routers like this is to
have one or more threads loop in userspace over a memory mapped NIC buffer.
Most of these interfaces are highly proprietary. Netmap provides the
relative programmatic simplicity of a TAP-type interface with the zero-copy
performance of the mapped buffering.
