From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2D821C3B186 for ; Wed, 12 Feb 2020 12:31:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 04FC420873 for ; Wed, 12 Feb 2020 12:31:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="GqhNMcnQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727781AbgBLMbt (ORCPT ); Wed, 12 Feb 2020 07:31:49 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:28958 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725887AbgBLMbt (ORCPT ); Wed, 12 Feb 2020 07:31:49 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1581510708; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=DkuFJgCWon69tEItX6xkmXrSdlha2NBDOEqvvQkjjyw=; b=GqhNMcnQuGUHkJdaQdxa3AF2+52cpMsyHoPTBNWFLl39rZWubhxjUFxEP/+kJCoJSKocA2 i/APKlLlr18A2/rk7+94CxCrLcOLtUW0VXjLQ3N6z0xiEhihzdZ42GwkBe7Byg/tgtuQAP WMC266RckfESC+dpkRvCeAeRjo3PB7g= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-341-coPtXN7cN3qSXUd7zsoJqQ-1; Wed, 12 Feb 2020 07:31:46 -0500 X-MC-Unique: coPtXN7cN3qSXUd7zsoJqQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id DCD1F107ACCA; Wed, 12 Feb 2020 12:31:44 +0000 (UTC) Received: from localhost.localdomain (wsfd-netdev76.ntdv.lab.eng.bos.redhat.com [10.19.188.157]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0A65C27061; Wed, 12 Feb 2020 12:31:40 +0000 (UTC) From: Eelco Chaudron To: bpf@vger.kernel.org Cc: davem@davemloft.net, netdev@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net, kafai@fb.com, songliubraving@fb.com, yhs@fb.com, andriin@fb.com, toke@redhat.com Subject: [PATCH bpf-next] libbpf: Add support for dynamic program attach target Date: Wed, 12 Feb 2020 12:31:22 +0000 Message-Id: <158151067149.71757.2222114135650741733.stgit@xdp-tutorial> User-Agent: StGit/0.19 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Content-Transfer-Encoding: quoted-printable Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Currently when you want to attach a trace program to a bpf program the section name needs to match the tracepoint/function semantics. However the addition of the bpf_program__set_attach_target() API allows you to specify the tracepoint/function dynamically. The call flow would look something like this: xdp_fd =3D bpf_prog_get_fd_by_id(id); trace_obj =3D bpf_object__open_file("func.o", NULL); prog =3D bpf_object__find_program_by_title(trace_obj, "fentry/myfunc"); bpf_program__set_attach_target(prog, xdp_fd, "fentry/xdpfilt_blk_all"); bpf_object__load(trace_obj) Signed-off-by: Eelco Chaudron --- tools/lib/bpf/libbpf.c | 41 +++++++++++++++++++++++++++++++++++-----= - tools/lib/bpf/libbpf.h | 4 ++++ tools/lib/bpf/libbpf.map | 1 + 3 files changed, 40 insertions(+), 6 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 514b1a524abb..2ce879c301bb 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -4933,15 +4933,16 @@ load_program(struct bpf_program *prog, struct bpf= _insn *insns, int insns_cnt, return ret; } =20 -static int libbpf_find_attach_btf_id(struct bpf_program *prog); +static int libbpf_find_attach_btf_id(struct bpf_program *prog, + const char *name); =20 int bpf_program__load(struct bpf_program *prog, char *license, __u32 ker= n_ver) { int err =3D 0, fd, i, btf_id; =20 - if (prog->type =3D=3D BPF_PROG_TYPE_TRACING || - prog->type =3D=3D BPF_PROG_TYPE_EXT) { - btf_id =3D libbpf_find_attach_btf_id(prog); + if ((prog->type =3D=3D BPF_PROG_TYPE_TRACING || + prog->type =3D=3D BPF_PROG_TYPE_EXT) && !prog->attach_btf_id) { + btf_id =3D libbpf_find_attach_btf_id(prog, NULL); if (btf_id <=3D 0) return btf_id; prog->attach_btf_id =3D btf_id; @@ -6202,6 +6203,31 @@ void bpf_program__set_expected_attach_type(struct = bpf_program *prog, prog->expected_attach_type =3D type; } =20 +int bpf_program__set_attach_target(struct bpf_program *prog, + int attach_prog_fd, + const char *attach_func_name) +{ + __u32 org_attach_prog_fd; + int btf_id; + + if (!prog || attach_prog_fd < 0 || !attach_func_name) + return -EINVAL; + + org_attach_prog_fd =3D prog->attach_prog_fd; + prog->attach_prog_fd =3D attach_prog_fd; + + btf_id =3D libbpf_find_attach_btf_id(prog, + attach_func_name); + + if (btf_id < 0) { + prog->attach_prog_fd =3D org_attach_prog_fd; + return btf_id; + } + + prog->attach_btf_id =3D btf_id; + return 0; +} + #define BPF_PROG_SEC_IMPL(string, ptype, eatype, is_attachable, btf, aty= pe) \ { string, sizeof(string) - 1, ptype, eatype, is_attachable, btf, atype = } =20 @@ -6633,13 +6659,16 @@ static int libbpf_find_prog_btf_id(const char *na= me, __u32 attach_prog_fd) return err; } =20 -static int libbpf_find_attach_btf_id(struct bpf_program *prog) +static int libbpf_find_attach_btf_id(struct bpf_program *prog, + const char *name) { enum bpf_attach_type attach_type =3D prog->expected_attach_type; __u32 attach_prog_fd =3D prog->attach_prog_fd; - const char *name =3D prog->section_name; int i, err; =20 + if (!name) + name =3D prog->section_name; + if (!name) return -EINVAL; =20 diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index 3fe12c9d1f92..02fc58a21a7f 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -334,6 +334,10 @@ LIBBPF_API void bpf_program__set_expected_attach_type(struct bpf_program *prog, enum bpf_attach_type type); =20 +LIBBPF_API int +bpf_program__set_attach_target(struct bpf_program *prog, int attach_prog= _fd, + const char *attach_func_name); + LIBBPF_API bool bpf_program__is_socket_filter(const struct bpf_program *= prog); LIBBPF_API bool bpf_program__is_tracepoint(const struct bpf_program *pro= g); LIBBPF_API bool bpf_program__is_raw_tracepoint(const struct bpf_program = *prog); diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index b035122142bb..8aba5438a3f0 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -230,6 +230,7 @@ LIBBPF_0.0.7 { bpf_program__name; bpf_program__is_extension; bpf_program__is_struct_ops; + bpf_program__set_attach_target; bpf_program__set_extension; bpf_program__set_struct_ops; btf__align_of;