This patchset adds two kfunc helpers, bpf_xdp_get_xfrm_state() and bpf_xdp_xfrm_state_release() that wrap xfrm_state_lookup() and xfrm_state_put(). The intent is to support software RSS (via XDP) for the ongoing/upcoming ipsec pcpu work [0]. Recent experiments performed on (hopefully) reproducible AWS testbeds indicate that single tunnel pcpu ipsec can reach line rate on 100G ENA nics.
Note this patchset only tests/shows generic xfrm_state access. The "secret sauce" (if you can really even call it that) involves accessing a soon-to-be-upstreamed pcpu_num field in xfrm_state. Early example is available here [1].
[0]: https://datatracker.ietf.org/doc/draft-ietf-ipsecme-multi-sa-performance/03/ [1]: https://github.com/danobi/xdp-tools/blob/e89a1c617aba3b50d990f779357d6ce2863...
Changes from v4: * Fixup commit message for selftest * Set opts->error -ENOENT for !x * Revert single file xfrm + bpf
Changes from v3: * Place all xfrm bpf integrations in xfrm_bpf.c * Avoid using nval as a temporary * Rebase to bpf-next * Remove extraneous __failure_unpriv annotation for verifier tests
Changes from v2: * Fix/simplify BPF_CORE_WRITE_BITFIELD() algorithm * Added verifier tests for bitfield writes * Fix state leakage across test_tunnel subtests
Changes from v1: * Move xfrm tunnel tests to test_progs * Fix writing to opts->error when opts is invalid * Use __bpf_kfunc_start_defs() * Remove unused vxlanhdr definition * Add and use BPF_CORE_WRITE_BITFIELD() macro * Make series bisect clean
Changes from RFCv2: * Rebased to ipsec-next * Fix netns leak
Changes from RFCv1: * Add Antony's commit tags * Add KF_ACQUIRE and KF_RELEASE semantics
Daniel Xu (9): bpf: xfrm: Add bpf_xdp_get_xfrm_state() kfunc bpf: xfrm: Add bpf_xdp_xfrm_state_release() kfunc libbpf: Add BPF_CORE_WRITE_BITFIELD() macro bpf: selftests: test_loader: Support __btf_path() annotation bpf: selftests: Add verifier tests for CO-RE bitfield writes bpf: selftests: test_tunnel: Setup fresh topology for each subtest bpf: selftests: test_tunnel: Use vmlinux.h declarations bpf: selftests: Move xfrm tunnel test to test_progs bpf: xfrm: Add selftest for bpf_xdp_get_xfrm_state()
include/net/xfrm.h | 9 + net/xfrm/Makefile | 1 + net/xfrm/xfrm_policy.c | 2 + net/xfrm/xfrm_state_bpf.c | 130 ++++++++++++++ tools/lib/bpf/bpf_core_read.h | 32 ++++ .../selftests/bpf/prog_tests/test_tunnel.c | 162 +++++++++++++++++- .../selftests/bpf/prog_tests/verifier.c | 2 + tools/testing/selftests/bpf/progs/bpf_misc.h | 1 + .../selftests/bpf/progs/bpf_tracing_net.h | 1 + .../selftests/bpf/progs/test_tunnel_kern.c | 138 ++++++++------- .../bpf/progs/verifier_bitfield_write.c | 100 +++++++++++ tools/testing/selftests/bpf/test_loader.c | 7 + tools/testing/selftests/bpf/test_tunnel.sh | 92 ---------- 13 files changed, 522 insertions(+), 155 deletions(-) create mode 100644 net/xfrm/xfrm_state_bpf.c create mode 100644 tools/testing/selftests/bpf/progs/verifier_bitfield_write.c