From 55cc3768473e139483be8f17796b50d21788953f Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Wed, 19 Jul 2023 16:08:54 +0200 Subject: libbpf: Add link-based API for tcx Implement tcx BPF link support for libbpf. The bpf_program__attach_fd() API has been refactored slightly in order to pass bpf_link_create_opts pointer as input. A new bpf_program__attach_tcx() has been added on top of this which allows for passing all relevant data via extensible struct bpf_tcx_opts. The program sections tcx/ingress and tcx/egress correspond to the hook locations for tc ingress and egress, respectively. For concrete usage examples, see the extensive selftests that have been developed as part of this series. Signed-off-by: Daniel Borkmann Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20230719140858.13224-5-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov --- tools/lib/bpf/bpf.c | 20 +++++++++++++++-- tools/lib/bpf/bpf.h | 5 +++++ tools/lib/bpf/libbpf.c | 58 ++++++++++++++++++++++++++++++++++++++++-------- tools/lib/bpf/libbpf.h | 15 +++++++++++++ tools/lib/bpf/libbpf.map | 1 + 5 files changed, 88 insertions(+), 11 deletions(-) (limited to 'tools') diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index 4131d3a1484b..c9b6b311a441 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -719,9 +719,9 @@ int bpf_link_create(int prog_fd, int target_fd, const struct bpf_link_create_opts *opts) { const size_t attr_sz = offsetofend(union bpf_attr, link_create); - __u32 target_btf_id, iter_info_len; + __u32 target_btf_id, iter_info_len, relative_id; + int fd, err, relative_fd; union bpf_attr attr; - int fd, err; if (!OPTS_VALID(opts, bpf_link_create_opts)) return libbpf_err(-EINVAL); @@ -783,6 +783,22 @@ int bpf_link_create(int prog_fd, int target_fd, if (!OPTS_ZEROED(opts, netfilter)) return libbpf_err(-EINVAL); break; + case BPF_TCX_INGRESS: + case BPF_TCX_EGRESS: + relative_fd = OPTS_GET(opts, tcx.relative_fd, 0); + relative_id = OPTS_GET(opts, tcx.relative_id, 0); + if (relative_fd && relative_id) + return libbpf_err(-EINVAL); + if (relative_id) { + attr.link_create.tcx.relative_id = relative_id; + attr.link_create.flags |= BPF_F_ID; + } else { + attr.link_create.tcx.relative_fd = relative_fd; + } + attr.link_create.tcx.expected_revision = OPTS_GET(opts, tcx.expected_revision, 0); + if (!OPTS_ZEROED(opts, tcx)) + return libbpf_err(-EINVAL); + break; default: if (!OPTS_ZEROED(opts, flags)) return libbpf_err(-EINVAL); diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h index 49e9d88fd9cf..044a74ffc38a 100644 --- a/tools/lib/bpf/bpf.h +++ b/tools/lib/bpf/bpf.h @@ -401,6 +401,11 @@ struct bpf_link_create_opts { __s32 priority; __u32 flags; } netfilter; + struct { + __u32 relative_fd; + __u32 relative_id; + __u64 expected_revision; + } tcx; }; size_t :0; }; diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 0f6913e1059b..17883f5a44b9 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -134,6 +134,7 @@ static const char * const link_type_name[] = { [BPF_LINK_TYPE_KPROBE_MULTI] = "kprobe_multi", [BPF_LINK_TYPE_STRUCT_OPS] = "struct_ops", [BPF_LINK_TYPE_NETFILTER] = "netfilter", + [BPF_LINK_TYPE_TCX] = "tcx", }; static const char * const map_type_name[] = { @@ -11854,11 +11855,10 @@ static int attach_lsm(const struct bpf_program *prog, long cookie, struct bpf_li } static struct bpf_link * -bpf_program__attach_fd(const struct bpf_program *prog, int target_fd, int btf_id, - const char *target_name) +bpf_program_attach_fd(const struct bpf_program *prog, + int target_fd, const char *target_name, + const struct bpf_link_create_opts *opts) { - DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts, - .target_btf_id = btf_id); enum bpf_attach_type attach_type; char errmsg[STRERR_BUFSIZE]; struct bpf_link *link; @@ -11876,7 +11876,7 @@ bpf_program__attach_fd(const struct bpf_program *prog, int target_fd, int btf_id link->detach = &bpf_link__detach_fd; attach_type = bpf_program__expected_attach_type(prog); - link_fd = bpf_link_create(prog_fd, target_fd, attach_type, &opts); + link_fd = bpf_link_create(prog_fd, target_fd, attach_type, opts); if (link_fd < 0) { link_fd = -errno; free(link); @@ -11892,19 +11892,54 @@ bpf_program__attach_fd(const struct bpf_program *prog, int target_fd, int btf_id struct bpf_link * bpf_program__attach_cgroup(const struct bpf_program *prog, int cgroup_fd) { - return bpf_program__attach_fd(prog, cgroup_fd, 0, "cgroup"); + return bpf_program_attach_fd(prog, cgroup_fd, "cgroup", NULL); } struct bpf_link * bpf_program__attach_netns(const struct bpf_program *prog, int netns_fd) { - return bpf_program__attach_fd(prog, netns_fd, 0, "netns"); + return bpf_program_attach_fd(prog, netns_fd, "netns", NULL); } struct bpf_link *bpf_program__attach_xdp(const struct bpf_program *prog, int ifindex) { /* target_fd/target_ifindex use the same field in LINK_CREATE */ - return bpf_program__attach_fd(prog, ifindex, 0, "xdp"); + return bpf_program_attach_fd(prog, ifindex, "xdp", NULL); +} + +struct bpf_link * +bpf_program__attach_tcx(const struct bpf_program *prog, int ifindex, + const struct bpf_tcx_opts *opts) +{ + LIBBPF_OPTS(bpf_link_create_opts, link_create_opts); + __u32 relative_id; + int relative_fd; + + if (!OPTS_VALID(opts, bpf_tcx_opts)) + return libbpf_err_ptr(-EINVAL); + + relative_id = OPTS_GET(opts, relative_id, 0); + relative_fd = OPTS_GET(opts, relative_fd, 0); + + /* validate we don't have unexpected combinations of non-zero fields */ + if (!ifindex) { + pr_warn("prog '%s': target netdevice ifindex cannot be zero\n", + prog->name); + return libbpf_err_ptr(-EINVAL); + } + if (relative_fd && relative_id) { + pr_warn("prog '%s': relative_fd and relative_id cannot be set at the same time\n", + prog->name); + return libbpf_err_ptr(-EINVAL); + } + + link_create_opts.tcx.expected_revision = OPTS_GET(opts, expected_revision, 0); + link_create_opts.tcx.relative_fd = relative_fd; + link_create_opts.tcx.relative_id = relative_id; + link_create_opts.flags = OPTS_GET(opts, flags, 0); + + /* target_fd/target_ifindex use the same field in LINK_CREATE */ + return bpf_program_attach_fd(prog, ifindex, "tcx", &link_create_opts); } struct bpf_link *bpf_program__attach_freplace(const struct bpf_program *prog, @@ -11926,11 +11961,16 @@ struct bpf_link *bpf_program__attach_freplace(const struct bpf_program *prog, } if (target_fd) { + LIBBPF_OPTS(bpf_link_create_opts, target_opts); + btf_id = libbpf_find_prog_btf_id(attach_func_name, target_fd); if (btf_id < 0) return libbpf_err_ptr(btf_id); - return bpf_program__attach_fd(prog, target_fd, btf_id, "freplace"); + target_opts.target_btf_id = btf_id; + + return bpf_program_attach_fd(prog, target_fd, "freplace", + &target_opts); } else { /* no target, so use raw_tracepoint_open for compatibility * with old kernels diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index 674e5788eb10..55b97b208754 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -733,6 +733,21 @@ LIBBPF_API struct bpf_link * bpf_program__attach_netfilter(const struct bpf_program *prog, const struct bpf_netfilter_opts *opts); +struct bpf_tcx_opts { + /* size of this struct, for forward/backward compatibility */ + size_t sz; + __u32 flags; + __u32 relative_fd; + __u32 relative_id; + __u64 expected_revision; + size_t :0; +}; +#define bpf_tcx_opts__last_field expected_revision + +LIBBPF_API struct bpf_link * +bpf_program__attach_tcx(const struct bpf_program *prog, int ifindex, + const struct bpf_tcx_opts *opts); + struct bpf_map; LIBBPF_API struct bpf_link *bpf_map__attach_struct_ops(const struct bpf_map *map); diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 8d1608643c33..9c7538dd5835 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -397,4 +397,5 @@ LIBBPF_1.3.0 { bpf_obj_pin_opts; bpf_prog_detach_opts; bpf_program__attach_netfilter; + bpf_program__attach_tcx; } LIBBPF_1.2.0; -- cgit v1.2.3