Subject: [RFC net-next 00/14] XDP in tx path

From: Prashant Bhole <[email-masked]>
Date: Wed, 18 Dec 2019 17:10:36 +0900

This series introduces tx path XDP. RFC also includes usage of the
feature in tun driver. Later both can be posted separately. Another
possible use of this feature can be in veth driver. It can improve
container networking where veth pair links the host and the container.
Host can set ACL by setting tx path XDP to the veth iface.

It was originally a part of Jason Wang's work "XDP offload with
virtio-net" [1]. In order to simplify this work we decided to split
it and introduce tx path XDP separately in this set.

The performance improvment can be seen when an XDP program is attached
to tun tx path opposed to rx path in the guest.

* Case 1: When packets are XDP_REDIRECT'ed towards tun.

                     virtio-net rx XDP      tun tx XDP
  xdp1(XDP_DROP)        2.57 Mpps           12.90 Mpps
  xdp2(XDP_TX)          1.53 Mpps            7.15 Mpps

* Case 2: When packets are pass through bridge towards tun

                     virtio-net rx XDP      tun tx XDP
  xdp1(XDP_DROP)        0.99 Mpps           1.00 Mpps
  xdp2(XDP_TX)          1.19 Mpps           0.97 Mpps

Since this set modifies tun and vhost_net, below are the netperf
performance numbers.

    Netperf_test       Before      After   Difference
  UDP_STREAM 18byte     90.14       88.77    -1.51%
  UDP_STREAM 1472byte   6955        6658     -4.27%
  TCP STREAM            9409        9402     -0.07%
  UDP_RR                12658       13030    +2.93%
  TCP_RR                12711       12831    +0.94%

XDP_REDIRECT will be handled later because we need to come up with
proper way to handle it in tx path.

Patches 1-4 are related to adding tx path XDP support.
Patches 5-14 implement tx path XDP in tun driver.

[1]: https://netdevconf.info/0x13/session.html?xdp-offload-with-virtio-net

David Ahern (2):
  net: add tx path XDP support
  tun: set tx path XDP program

Jason Wang (2):
  net: core: rename netif_receive_generic_xdp() to do_generic_xdp_core()
  net: core: export do_xdp_generic_core()

Prashant Bhole (10):
  tools: sync kernel uapi/linux/if_link.h header
  libbpf: API for tx path XDP support
  samples/bpf: xdp1, add XDP tx support
  tuntap: check tun_msg_ctl type at necessary places
  vhost_net: user tap recvmsg api to access ptr ring
  tuntap: remove usage of ptr ring in vhost_net
  tun: run XDP program in tx path
  tun: add a way to inject tx path packet into Rx path
  tun: handle XDP_TX action of tx path XDP program
  tun: run xdp prog when tun is read from file interface

 drivers/net/tap.c                  |  42 +++--
 drivers/net/tun.c                  | 278 +++++++++++++++++++++++++----
 drivers/vhost/net.c                |  77 ++++----
 include/linux/if_tap.h             |   5 -
 include/linux/if_tun.h             |  23 ++-
 include/linux/netdevice.h          |   6 +-
 include/uapi/linux/if_link.h       |   1 +
 net/core/dev.c                     |  39 ++--
 net/core/rtnetlink.c               | 112 +++++++++++-
 samples/bpf/xdp1_user.c            |  28 ++-
 tools/include/uapi/linux/if_link.h |   2 +
 tools/lib/bpf/libbpf.h             |   4 +
 tools/lib/bpf/libbpf.map           |   3 +
 tools/lib/bpf/netlink.c            |  77 +++++++-
 14 files changed, 571 insertions(+), 126 deletions(-)

-- 
2.21.0