On Fri, 2 Aug 2019 12:45:55 +0530 Nilesh <[email protected]> wrote:
> Hello, > > We are building an application where a majority of the packets on the > fast path are handled by DPDK, but a small subset of packets on the slow > path need to be redirected to a legacy userspace socket program that > runs over the kernel TCP/IP stack. Therefore, we are trying to inject > the slow path packets received by DPDK into the kernel via TUN/TAP device. > > We have done the following: we created a tun device, assigned it an IP > address, and bound the legacy socket program to this address. The DPDK > program reads all packets from the NIC and writes the slow path packets > into this tun device. These packets are then successfully received by > the legacy socket program. However, we are unable to get this to work > with DPDK's tun/tap devices (dtun/dtap). > > When we use dtap then packet is received in dtap0 (can be seen in > wireshark) but not reached the socket program. > When we use dtun then packet is received in dtun0 (rx value increases > but is not captured by wireshark) and not reached the socket program. > (We enabled ip_forwarding and disabled rp_filter for both "all" and > "dtun0" iface) > (Reference:https://doc.dpdk.org/guides/nics/tap.html) > <https://doc.dpdk.org/guides/nics/tap.html> > > Any pointers regarding how to do this using dtun/dtap will be helpful. > Are we missing anything due to which linux tun device is working but > dtun/dtap isn't? > > System specification : > 2 machines with > Distributor ID: Ubuntu > Description: Ubuntu 18.04.2 LTS > Release: 18.04 > Codename: bionic > > Kernel: 4.15.0-55-generic > *DPDK* version: 19.05.0 > > Hardware: > CPU: Intel(R) Xeon(R) CPU E5-2650 v4 @ 2.20GHz > NIC 1: Intel Corporation Ethernet Controller XL710 for 40GbE QSFP+ (i40e) > > (If any extra setup configuration information required will be provided) > Make sure tap device in kernel is up? You might try virtio as faster exception path. https://doc.dpdk.org/guides-18.08/howto/virtio_user_as_exceptional_path.html
