The first patch of this series is a documentation fix.
The second patch allows BPF helpers to accept memory regions of fixed size without doing runtime size checks.
The two next 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 It was superseded by series [2] by Kumar Kartikeya Dwivedi, which implements this functionality using unstable helpers.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 third patch adds new helpers to issue and check SYN cookies without binding to a socket, which is useful in the synproxy scenario.
The fourth patch adds a selftest, which includes 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 last two patches expose the new helpers to TC BPF and extend the selftest.
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.
v3 changes:
Moved some patches from bpf to bpf-next, dropped the patch that changed error codes, split the new helpers into IPv4/IPv6, added verifier functionality to accept memory regions of fixed size.
v4 changes:
Converted the selftest to the test_progs runner. Replaced some deprecated functions in xdp_synproxy userspace helper.
v5 changes:
Fixed a bug in the selftest. Added questionable functionality to support new helpers in TC BPF, added selftests for it.
v6 changes:
Wrap the new helpers themselves into #ifdef CONFIG_SYN_COOKIES, replaced fclose with pclose and fixed the MSS for IPv6 in the selftest.
v7 changes:
Fixed the off-by-one error in indices, changed the section name to "xdp", added missing kernel config options to vmtest in CI.
v8 changes:
Properly rebased, dropped the first patch (the same change was applied by someone else), updated the cover letter.
v9 changes:
Fixed selftests for no_alu32.
v10 changes:
Selftests for s390x were blacklisted due to lack of support of kfunc, rebased the series, split selftests to separate commits, created ARG_PTR_TO_FIXED_SIZE_MEM and packed arg_size, addressed the rest of comments.
[1]: https://lore.kernel.org/bpf/20211020095815.GJ28644@breakpoint.cc/t/ [2]: https://lore.kernel.org/bpf/20220114163953.1455836-1-memxor@gmail.com/ [3]: https://netdevconf.info/0x15/session.html?Accelerating-synproxy-with-XDP
Maxim Mikityanskiy (6): bpf: Fix documentation of th_len in bpf_tcp_{gen,check}_syncookie bpf: Allow helpers to accept pointers with a fixed size bpf: Add helpers to issue and check SYN cookies in XDP selftests/bpf: Add selftests for raw syncookie helpers bpf: Allow the new syncookie helpers to work with SKBs selftests/bpf: Add selftests for raw syncookie helpers in TC mode
include/linux/bpf.h | 13 + include/net/tcp.h | 1 + include/uapi/linux/bpf.h | 88 +- kernel/bpf/verifier.c | 43 +- net/core/filter.c | 128 +++ net/ipv4/tcp_input.c | 3 +- scripts/bpf_doc.py | 4 + tools/include/uapi/linux/bpf.h | 88 +- tools/testing/selftests/bpf/.gitignore | 1 + tools/testing/selftests/bpf/Makefile | 3 +- .../selftests/bpf/prog_tests/xdp_synproxy.c | 183 ++++ .../selftests/bpf/progs/xdp_synproxy_kern.c | 833 ++++++++++++++++++ tools/testing/selftests/bpf/xdp_synproxy.c | 466 ++++++++++ 13 files changed, 1833 insertions(+), 21 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/xdp_synproxy.c create mode 100644 tools/testing/selftests/bpf/progs/xdp_synproxy_kern.c create mode 100644 tools/testing/selftests/bpf/xdp_synproxy.c