From patchwork Mon Feb 17 11:01:49 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Eelco Chaudron X-Patchwork-Id: 1239114 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=LsFOb7Fg; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 48Lh08390yz9sRR for ; Mon, 17 Feb 2020 22:02:32 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728563AbgBQLCa (ORCPT ); Mon, 17 Feb 2020 06:02:30 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:58611 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728516AbgBQLCa (ORCPT ); Mon, 17 Feb 2020 06:02:30 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1581937349; 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=jKUCIeprTRWb1KGKCWqYWiN5G08eSGkYzc2Y5TKQIOA=; b=LsFOb7FgCxYJaQqxGl+VIUNz3KDiKYKIMYJpaFGAMJTZO6+WztIbJK25oQeiI8YAWwa0SG lwILSCLQ5g/dSRSXuLvxUROwla4dWgblQNZWxHsT0nyg1zgyGUjggA70bNXQN+Bk+xF1qG DIKOuJ+DH8p93eafoOX+mnUBKG4ZLw8= 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-307-ZqqOYk9PM5CAWLJpsI-KeA-1; Mon, 17 Feb 2020 06:02:24 -0500 X-MC-Unique: ZqqOYk9PM5CAWLJpsI-KeA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 3A3A2DB6D; Mon, 17 Feb 2020 11:02:22 +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 E9AAB9053C; Mon, 17 Feb 2020 11:02:17 +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 v3] libbpf: Add support for dynamic program attach target Date: Mon, 17 Feb 2020 11:01:49 +0000 Message-Id: <158193725120.96608.9449808053785640511.stgit@xdp-tutorial> User-Agent: StGit/0.19 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 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 = bpf_prog_get_fd_by_id(id); trace_obj = bpf_object__open_file("func.o", NULL); prog = bpf_object__find_program_by_title(trace_obj, "fentry/myfunc"); bpf_program__set_expected_attach_type(prog, BPF_TRACE_FENTRY); bpf_program__set_attach_target(prog, xdp_fd, "xdpfilt_blk_all"); bpf_object__load(trace_obj) Signed-off-by: Eelco Chaudron Acked-by: Toke Høiland-Jørgensen --- v1 -> v2: Remove requirement for attach type hint in API v2 -> v3: Moved common warning to __find_vmlinux_btf_id, requested by Andrii Updated the xdp_bpf2bpf test to use this new API tools/lib/bpf/libbpf.c | 34 ++++++++++++++++++-- tools/lib/bpf/libbpf.h | 4 ++ tools/lib/bpf/libbpf.map | 1 + .../testing/selftests/bpf/prog_tests/xdp_bpf2bpf.c | 16 ++++++++- .../testing/selftests/bpf/progs/test_xdp_bpf2bpf.c | 4 +- 5 files changed, 50 insertions(+), 9 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 514b1a524abb..0c25d78fb5d8 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -4939,8 +4939,8 @@ int bpf_program__load(struct bpf_program *prog, char *license, __u32 kern_ver) { int err = 0, fd, i, btf_id; - if (prog->type == BPF_PROG_TYPE_TRACING || - prog->type == BPF_PROG_TYPE_EXT) { + if ((prog->type == BPF_PROG_TYPE_TRACING || + prog->type == BPF_PROG_TYPE_EXT) && !prog->attach_btf_id) { btf_id = libbpf_find_attach_btf_id(prog); if (btf_id <= 0) return btf_id; @@ -6583,6 +6583,9 @@ static inline int __find_vmlinux_btf_id(struct btf *btf, const char *name, else err = btf__find_by_name_kind(btf, name, BTF_KIND_FUNC); + if (err <= 0) + pr_warn("%s is not found in vmlinux BTF\n", name); + return err; } @@ -6655,8 +6658,6 @@ static int libbpf_find_attach_btf_id(struct bpf_program *prog) err = __find_vmlinux_btf_id(prog->obj->btf_vmlinux, name + section_defs[i].len, attach_type); - if (err <= 0) - pr_warn("%s is not found in vmlinux BTF\n", name); return err; } pr_warn("failed to identify btf_id based on ELF section name '%s'\n", name); @@ -8132,6 +8133,31 @@ void bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear) } } +int bpf_program__set_attach_target(struct bpf_program *prog, + int attach_prog_fd, + const char *attach_func_name) +{ + int btf_id; + + if (!prog || attach_prog_fd < 0 || !attach_func_name) + return -EINVAL; + + if (attach_prog_fd) + btf_id = libbpf_find_prog_btf_id(attach_func_name, + attach_prog_fd); + else + btf_id = __find_vmlinux_btf_id(prog->obj->btf_vmlinux, + attach_func_name, + prog->expected_attach_type); + + if (btf_id <= 0) + return btf_id; + + prog->attach_btf_id = btf_id; + prog->attach_prog_fd = attach_prog_fd; + return 0; +} + int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz) { int err = 0, n, len, start, end = -1; 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); +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 *prog); 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; diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_bpf2bpf.c b/tools/testing/selftests/bpf/prog_tests/xdp_bpf2bpf.c index 6b56bdc73ebc..513fdbf02b81 100644 --- a/tools/testing/selftests/bpf/prog_tests/xdp_bpf2bpf.c +++ b/tools/testing/selftests/bpf/prog_tests/xdp_bpf2bpf.c @@ -14,7 +14,7 @@ void test_xdp_bpf2bpf(void) struct test_xdp *pkt_skel = NULL; struct test_xdp_bpf2bpf *ftrace_skel = NULL; struct vip key4 = {.protocol = 6, .family = AF_INET}; - DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts); + struct bpf_program *prog; /* Load XDP program to introspect */ pkt_skel = test_xdp__open_and_load(); @@ -27,11 +27,21 @@ void test_xdp_bpf2bpf(void) bpf_map_update_elem(map_fd, &key4, &value4, 0); /* Load trace program */ - opts.attach_prog_fd = pkt_fd, - ftrace_skel = test_xdp_bpf2bpf__open_opts(&opts); + ftrace_skel = test_xdp_bpf2bpf__open(); if (CHECK(!ftrace_skel, "__open", "ftrace skeleton failed\n")) goto out; + /* Demonstrate the bpf_program__set_attach_target() API rather than + * the load with options, i.e. opts.attach_prog_fd. + */ + prog = *ftrace_skel->skeleton->progs[0].prog; + bpf_program__set_expected_attach_type(prog, BPF_TRACE_FENTRY); + bpf_program__set_attach_target(prog, pkt_fd, "_xdp_tx_iptunnel"); + + prog = *ftrace_skel->skeleton->progs[1].prog; + bpf_program__set_expected_attach_type(prog, BPF_TRACE_FEXIT); + bpf_program__set_attach_target(prog, pkt_fd, "_xdp_tx_iptunnel"); + err = test_xdp_bpf2bpf__load(ftrace_skel); if (CHECK(err, "__load", "ftrace skeleton failed\n")) goto out; diff --git a/tools/testing/selftests/bpf/progs/test_xdp_bpf2bpf.c b/tools/testing/selftests/bpf/progs/test_xdp_bpf2bpf.c index cb8a04ab7a78..b840fc9e3ed5 100644 --- a/tools/testing/selftests/bpf/progs/test_xdp_bpf2bpf.c +++ b/tools/testing/selftests/bpf/progs/test_xdp_bpf2bpf.c @@ -28,7 +28,7 @@ struct xdp_buff { } __attribute__((preserve_access_index)); __u64 test_result_fentry = 0; -SEC("fentry/_xdp_tx_iptunnel") +SEC("fentry/FUNC") int BPF_PROG(trace_on_entry, struct xdp_buff *xdp) { test_result_fentry = xdp->rxq->dev->ifindex; @@ -36,7 +36,7 @@ int BPF_PROG(trace_on_entry, struct xdp_buff *xdp) } __u64 test_result_fexit = 0; -SEC("fexit/_xdp_tx_iptunnel") +SEC("fexit/FUNC") int BPF_PROG(trace_on_exit, struct xdp_buff *xdp, int ret) { test_result_fexit = ret;