Subject: [PATCH bpf-next v2 0/3] New BPF helpers to accelerate synproxy

From: Maxim Mikityanskiy <[email-masked]>
Date: Mon, 24 Jan 2022 17:13:37 +0200

The first patch of this series is an improvement to the existing
syncookie BPF helper.

The two other patches add new functionality that allows XDP to
accelerate iptables synproxy.

v1 of this series [1] used to include a patch that exposed conntrack
lookup to BPF using stable helpers. It was superseded by series [2] by
Kumar Kartikeya Dwivedi, which implements this functionality using
unstable helpers.

The second patch adds new helpers to issue and check SYN cookies without
binding to a socket, which is useful in the synproxy scenario.

The third patch adds a selftest, which consists of a script, an XDP
program and a userspace control application. The XDP program uses
socketless SYN cookie helpers and queries conntrack status instead of
socket status. The userspace control application allows to tune
parameters of the XDP program. This program also serves as a minimal
example of usage of the new functionality.

The draft of the new functionality was presented on Netdev 0x15 [3].

v2 changes:

Split into two series, submitted bugfixes to bpf, dropped the conntrack
patches, implemented the timestamp cookie in BPF using bpf_loop, dropped
the timestamp cookie patch.

[1]: https://lore.kernel.org/bpf/[email-masked]/t/
[2]: https://lore.kernel.org/bpf/[email-masked]/
[3]: https://netdevconf.info/0x15/session.html?Accelerating-synproxy-with-XDP

Maxim Mikityanskiy (3):
  bpf: Make errors of bpf_tcp_check_syncookie distinguishable
  bpf: Add helpers to issue and check SYN cookies in XDP
  bpf: Add selftests for raw syncookie helpers

 include/net/tcp.h                             |   1 +
 include/uapi/linux/bpf.h                      |  75 +-
 net/core/filter.c                             | 128 ++-
 net/ipv4/tcp_input.c                          |   3 +-
 tools/include/uapi/linux/bpf.h                |  75 +-
 tools/testing/selftests/bpf/.gitignore        |   1 +
 tools/testing/selftests/bpf/Makefile          |   5 +-
 .../selftests/bpf/progs/xdp_synproxy_kern.c   | 743 ++++++++++++++++++
 .../selftests/bpf/test_xdp_synproxy.sh        |  71 ++
 tools/testing/selftests/bpf/xdp_synproxy.c    | 418 ++++++++++
 10 files changed, 1510 insertions(+), 10 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/progs/xdp_synproxy_kern.c
 create mode 100755 tools/testing/selftests/bpf/test_xdp_synproxy.sh
 create mode 100644 tools/testing/selftests/bpf/xdp_synproxy.c

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2.30.2