[dpdk-dev] [PATCH v3 0/2] TAP RSS eBPF cover letter

[Ophir Munk]

The patches of TAP RSS eBPF follow the RFC on this issue
https://dpdk.org/dev/patchwork/patch/31781/

v3 changes with respect to v2
=============================
* Add support for IPv6 RSS in BPF program
* Bug fixes
* Updated compatibility to kernel versions:
  eBPF requires Linux version 4.9 configured with BPF
* New license header (SPDX) for newly added files

v2 changes with respect to v1
=============================
* v2 has new commits organization (3 --> 2)
* BPF program was revised. It is successfully tested on
  IPv4 L3 L4 layers (compatible to mlx4 device)
* Licensing: no comments received for using "Dual BSD/GPL"
  string during BPF program loading to the kernel.
  (v1 and v2 are using the same license strings)
  Any comments are welcome.
* Compatibility to kernel versions:
  eBPF requires Linux version 4.2 configured with BPF. TAP PMD will
  successfully compile on systems with old or non-BPF configured kernels.
  During compilation time the required Linux headers are searched for.
  If they are not present missing definitions are locally added
  (tap_autoconf.h).
  If the kernel cannot support a BPF operation - at runtime it will
  gracefully reject the netlink message (with BPF) sent to it.

Commit #1:
net/tap: add eBPF instructions to TAP device
===========================================
  This commit introduces BPF program (tap_bpf_program.c)
  with a classifier and an action sections.
  The current implementation calculates RSS hash
  over L3 addresses and L4 ports.
  BPF program compilation is not part of dpdk compilation.
  This commit includes the eBPF machine instructions
  in the format of C arrays (tap_bpf_insns.c).

  The option to update the BPF program and download new machine
  instructions will be described in another commit.

Commit #2:
net/tap: implement RSS with eBPF classifier and action
======================================================
This commit builds and sends netlink messages to the kernel
that include BPF programs.
There is a single BPF classifier for each TAP queue. Packets
marked with an RSS queue will be directed to this queue using a traffic
control with "skbedit" action otherwise they will be pipelined to
the following rules.
There is a single BPF action for each RSS rule (may add more
to support IPv6).
The action is to calculate Toeplitz hash based on L3 addresses and L4 ports,
mark the packet with the RSS queue according the resulting hash,
then reclassify the packet.
Ophir Munk (2):
  net/tap: add eBPF instructions to TAP device
  net/tap: implement RSS with eBPF classifier and action

 drivers/net/tap/Makefile          |   31 +
 drivers/net/tap/rte_eth_tap.h     |    9 +-
 drivers/net/tap/tap_bpf.h         |   92 ++
 drivers/net/tap/tap_bpf_insns.c   | 1905 +++++++++++++++++++++++++++++++++++++
 drivers/net/tap/tap_bpf_program.c |  221 +++++
 drivers/net/tap/tap_flow.c        |  635 +++++++++++--
 drivers/net/tap/tap_flow.h        |   15 +
 drivers/net/tap/tap_rss.h         |   32 +
 drivers/net/tap/tap_tcmsgs.h      |    4 +
 9 files changed, 2848 insertions(+), 96 deletions(-)
 create mode 100644 drivers/net/tap/tap_bpf.h
 create mode 100644 drivers/net/tap/tap_bpf_insns.c
 create mode 100644 drivers/net/tap/tap_bpf_program.c
 create mode 100644 drivers/net/tap/tap_rss.h

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2.7.4