This series adds unstable conntrack lookup helpers using BPF kfunc support. The patch adding the lookup helper is based off of Maxim's recent patch to aid in rebasing their series on top of this, all adjusted to work with module kfuncs [0]. [0]: https://lore.kernel.org/bpf/20211019144655.3483197-8-maximmi@xxxxxxxxxx To enable returning a reference to struct nf_conn, the verifier is extended to support reference tracking for PTR_TO_BTF_ID, and kfunc is extended with support for working as acquire/release functions, similar to existing BPF helpers. kfunc returning pointer (limited to PTR_TO_BTF_ID in the kernel) can also return a PTR_TO_BTF_ID_OR_NULL now, typically needed when acquiring a resource can fail. kfunc can also receive PTR_TO_CTX and PTR_TO_MEM (with some limitations) as arguments now. There is also support for passing a mem, len pair as argument to kfunc now. In such cases, passing pointer to unsized type (void) is also permitted. Please see individual commits for details. Note 1: Patch 1 in this series makes the same change as b12f03104324 ("bpf: Fix bpf_check_mod_kfunc_call for built-in modules") in bpf tree, so there will be a conflict if patch 1 is applied against that commit. I incorporated the same diff change so that testing this set is possible (tests in patch 9 rely on it), but before applying this, I'll rebase and resend, after bpf tree is merged into bpf-next. Note 2: BPF CI needs to add the following to config to test the set. I did update the selftests config in patch 9, but not sure if that is enough. CONFIG_NETFILTER=y CONFIG_NF_DEFRAG_IPV4=y CONFIG_NF_DEFRAG_IPV6=y CONFIG_NF_CONNTRACK=y Changelog: ---------- v2 -> v3: v2: https://lore.kernel.org/bpf/20211209170929.3485242-1-memxor@xxxxxxxxx * Fix build error for !CONFIG_BPF_SYSCALL (Patchwork) RFC v1 -> v2: v1: https://lore.kernel.org/bpf/20211030144609.263572-1-memxor@xxxxxxxxx * Limit PTR_TO_MEM support to pointer to scalar, or struct with scalars (Alexei) * Use btf_id_set for checking acquire, release, ret type null (Alexei) * Introduce opts struct for CT helpers, move int err parameter to it * Add l4proto as parameter to CT helper's opts, remove separate tcp/udp helpers * Add support for mem, len argument pair to kfunc * Allow void * as pointer type for mem, len argument pair * Extend selftests to cover new additions to kfuncs * Copy ref_obj_id to PTR_TO_BTF_ID dst_reg on btf_struct_access, test it * Fix other misc nits, bugs, and expand commit messages Kumar Kartikeya Dwivedi (9): bpf: Refactor bpf_check_mod_kfunc_call bpf: Remove DEFINE_KFUNC_BTF_ID_SET bpf: Extend kfunc with PTR_TO_CTX, PTR_TO_MEM argument support bpf: Introduce mem, size argument pair support for kfunc bpf: Add reference tracking support to kfunc bpf: Track provenance for pointers formed from referenced PTR_TO_BTF_ID net/netfilter: Add unstable CT lookup helpers for XDP and TC-BPF selftests/bpf: Extend kfunc selftests selftests/bpf: Add test for unstable CT lookup API include/linux/bpf.h | 27 +- include/linux/bpf_verifier.h | 12 + include/linux/btf.h | 45 +++- kernel/bpf/btf.c | 218 ++++++++++++--- kernel/bpf/verifier.c | 232 +++++++++++----- net/bpf/test_run.c | 147 ++++++++++ net/core/filter.c | 27 ++ net/core/net_namespace.c | 1 + net/ipv4/tcp_bbr.c | 5 +- net/ipv4/tcp_cubic.c | 5 +- net/ipv4/tcp_dctcp.c | 5 +- net/netfilter/nf_conntrack_core.c | 252 ++++++++++++++++++ .../selftests/bpf/bpf_testmod/bpf_testmod.c | 5 +- tools/testing/selftests/bpf/config | 4 + .../testing/selftests/bpf/prog_tests/bpf_nf.c | 48 ++++ .../selftests/bpf/prog_tests/kfunc_call.c | 28 ++ .../selftests/bpf/progs/kfunc_call_test.c | 52 +++- .../bpf/progs/kfunc_call_test_fail1.c | 16 ++ .../bpf/progs/kfunc_call_test_fail2.c | 16 ++ .../bpf/progs/kfunc_call_test_fail3.c | 16 ++ .../bpf/progs/kfunc_call_test_fail4.c | 16 ++ .../bpf/progs/kfunc_call_test_fail5.c | 16 ++ .../bpf/progs/kfunc_call_test_fail6.c | 16 ++ .../bpf/progs/kfunc_call_test_fail7.c | 24 ++ .../bpf/progs/kfunc_call_test_fail8.c | 22 ++ .../testing/selftests/bpf/progs/test_bpf_nf.c | 113 ++++++++ 26 files changed, 1258 insertions(+), 110 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/bpf_nf.c create mode 100644 tools/testing/selftests/bpf/progs/kfunc_call_test_fail1.c create mode 100644 tools/testing/selftests/bpf/progs/kfunc_call_test_fail2.c create mode 100644 tools/testing/selftests/bpf/progs/kfunc_call_test_fail3.c create mode 100644 tools/testing/selftests/bpf/progs/kfunc_call_test_fail4.c create mode 100644 tools/testing/selftests/bpf/progs/kfunc_call_test_fail5.c create mode 100644 tools/testing/selftests/bpf/progs/kfunc_call_test_fail6.c create mode 100644 tools/testing/selftests/bpf/progs/kfunc_call_test_fail7.c create mode 100644 tools/testing/selftests/bpf/progs/kfunc_call_test_fail8.c create mode 100644 tools/testing/selftests/bpf/progs/test_bpf_nf.c -- 2.34.1
