From patchwork Thu May 25 11:00:59 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Westphal X-Patchwork-Id: 13255081 X-Patchwork-Delegate: bpf@iogearbox.net Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6D07BFBF2; Thu, 25 May 2023 11:01:23 +0000 (UTC) Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:237:300::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 81BC7C5; Thu, 25 May 2023 04:01:21 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1q28id-0004ic-LO; Thu, 25 May 2023 13:01:19 +0200 From: Florian Westphal To: Cc: andrii.nakryiko@gmail.com, ast@kernel.org, , dxu@dxuuu.xyz, qde@naccy.de, Florian Westphal Subject: [PATCH bpf-next 1/2] tools: libbpf: add netfilter link attach helper Date: Thu, 25 May 2023 13:00:59 +0200 Message-Id: <20230525110100.8212-2-fw@strlen.de> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20230525110100.8212-1-fw@strlen.de> References: <20230525110100.8212-1-fw@strlen.de> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-4.0 required=5.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_MED,SPF_HELO_PASS,SPF_PASS, T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: bpf@iogearbox.net Add new api function: bpf_program__attach_netfilter_opts. It takes a bpf program (netfilter type), and a pointer to a option struct that contains the desired attachment (protocol family, priority, hook location, ...). It returns a pointer to a 'bpf_link' structure or NULL on error. Next patch adds new netfilter_basic test that uses this function to attach a program to a few pf/hook/priority combinations. Suggested-by: Andrii Nakryiko Signed-off-by: Florian Westphal --- tools/lib/bpf/libbpf.c | 51 ++++++++++++++++++++++++++++++++++++++++ tools/lib/bpf/libbpf.h | 15 ++++++++++++ tools/lib/bpf/libbpf.map | 1 + 3 files changed, 67 insertions(+) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 5cca00979aae..033447aa0773 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -11811,6 +11811,57 @@ static int attach_iter(const struct bpf_program *prog, long cookie, struct bpf_l return libbpf_get_error(*link); } +struct bpf_link *bpf_program__attach_netfilter_opts(const struct bpf_program *prog, + const struct bpf_netfilter_opts *opts) +{ + const size_t attr_sz = offsetofend(union bpf_attr, link_create); + struct bpf_link *link; + int prog_fd, link_fd; + union bpf_attr attr; + + if (!OPTS_VALID(opts, bpf_netfilter_opts)) + return libbpf_err_ptr(-EINVAL); + + prog_fd = bpf_program__fd(prog); + if (prog_fd < 0) { + pr_warn("prog '%s': can't attach before loaded\n", prog->name); + return libbpf_err_ptr(-EINVAL); + } + + link = calloc(1, sizeof(*link)); + if (!link) + return libbpf_err_ptr(-ENOMEM); + link->detach = &bpf_link__detach_fd; + + memset(&attr, 0, attr_sz); + + attr.link_create.prog_fd = prog_fd; + attr.link_create.netfilter.pf = OPTS_GET(opts, pf, 0); + attr.link_create.netfilter.hooknum = OPTS_GET(opts, hooknum, 0); + attr.link_create.netfilter.priority = OPTS_GET(opts, priority, 0); + attr.link_create.netfilter.flags = OPTS_GET(opts, flags, 0); + + link_fd = syscall(__NR_bpf, BPF_LINK_CREATE, &attr, attr_sz); + + link->fd = ensure_good_fd(link_fd); + + if (link->fd < 0) { + char errmsg[STRERR_BUFSIZE]; + + link_fd = -errno; + free(link); + pr_warn("prog '%s': failed to attach to pf:%d,hooknum:%d:prio:%d: %s\n", + prog->name, + OPTS_GET(opts, pf, 0), + OPTS_GET(opts, hooknum, 0), + OPTS_GET(opts, priority, 0), + libbpf_strerror_r(link_fd, errmsg, sizeof(errmsg))); + return libbpf_err_ptr(link_fd); + } + + return link; +} + struct bpf_link *bpf_program__attach(const struct bpf_program *prog) { struct bpf_link *link = NULL; diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index 754da73c643b..081beb95a097 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -718,6 +718,21 @@ LIBBPF_API struct bpf_link * bpf_program__attach_freplace(const struct bpf_program *prog, int target_fd, const char *attach_func_name); +struct bpf_netfilter_opts { + /* size of this struct, for forward/backward compatibility */ + size_t sz; + + __u32 pf; + __u32 hooknum; + __s32 priority; + __u32 flags; +}; +#define bpf_netfilter_opts__last_field flags + +LIBBPF_API struct bpf_link * +bpf_program__attach_netfilter_opts(const struct bpf_program *prog, + const struct bpf_netfilter_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 7521a2fb7626..e13d60608bf3 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -395,4 +395,5 @@ LIBBPF_1.2.0 { LIBBPF_1.3.0 { global: bpf_obj_pin_opts; + bpf_program__attach_netfilter_opts; } LIBBPF_1.2.0;