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 It was superseded by series [2] by Kumar Kartikeya Dwivedi, which implements this functionality using unstable helpers.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/20211020095815.GJ28644@xxxxxxxxxxxxx/t/ [2]: https://lore.kernel.org/bpf/20220114163953.1455836-1-memxor@xxxxxxxxx/ [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 -- 2.30.2
