Based on previous discussion[0], we determined that it would be beneficial to rework bpf_redirect_neigh() so the caller can supply the nexthop information (e.g., from a previous call to bpf_fib_lookup()). This way, the two helpers can be combined without incurring a second FIB lookup to find the nexthop, and bpf_fib_lookup() becomes usable even if no nexthop entry currently exists. This patch (and accompanying selftest update) accomplishes this by way of an optional paramter to bpf_redirect_neigh(). This series is against the -bpf tree, since we need to change this call signature before it becomes API. As a companion change, it also adds a flag to bpf_fib_lookup() that will make it skip the neighbour lookup, for cases where the caller knows it is likely for fail anyway, and wants to go straight to bpf_redirect_neigh(). [0] https://lore.kernel.org/bpf/393e17fc-d187-3a8d-2f0d-a627c7c63fca@xxxxxxxxxxxxx/ Changelog: v2: - Add 'unused' member to fill hole in bpf_redir_neigh struct (David Ahern) - Fix compilation with INET/INET6 disabled - properly this time (kbot) - Add back the BPF_FIB_LOOKUP_SKIP_NEIGH flag as new patch 2 (Daniel) v1: - Rebase on -bpf tree - Fix compilation with INET/INET6 disabled (kbot) - Keep v4/v6 signatures similar, use internal flag (Daniel) - Use a separate selftest BPF program instead of modifying existing one (Daniel) - Fix a few style nits (David Ahern) --- Toke Høiland-Jørgensen (3): bpf_redirect_neigh: Support supplying the nexthop as a helper parameter bpf_fib_lookup: optionally skip neighbour lookup selftests: Update test_tc_redirect.sh to use the modified bpf_redirect_neigh() include/uapi/linux/bpf.h | 10 +- net/core/filter.c | 16 +- tools/include/uapi/linux/bpf.h | 10 +- .../selftests/bpf/progs/test_tc_neigh.c | 5 +- .../selftests/bpf/progs/test_tc_neigh_fib.c | 153 ++++++++++++++++++ .../testing/selftests/bpf/test_tc_redirect.sh | 18 ++- 6 files changed, 197 insertions(+), 15 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/test_tc_neigh_fib.c
