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=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 7FE67C433ED for ; Wed, 21 Apr 2021 22:41:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 36112613C2 for ; Wed, 21 Apr 2021 22:41:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235693AbhDUWmQ (ORCPT ); Wed, 21 Apr 2021 18:42:16 -0400 Received: from www62.your-server.de ([213.133.104.62]:42730 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229706AbhDUWmQ (ORCPT ); Wed, 21 Apr 2021 18:42:16 -0400 Received: from sslproxy01.your-server.de ([78.46.139.224]) by www62.your-server.de with esmtpsa (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92.3) (envelope-from ) id 1lZLXP-000Cs0-2c; Thu, 22 Apr 2021 00:41:39 +0200 Received: from [85.7.101.30] (helo=linux.home) by sslproxy01.your-server.de with esmtpsa (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lZLXO-0001R9-Oa; Thu, 22 Apr 2021 00:41:38 +0200 Subject: Re: [PATCH bpf-next v3 3/3] libbpf: add selftests for TC-BPF API To: =?UTF-8?Q?Toke_H=c3=b8iland-J=c3=b8rgensen?= , Kumar Kartikeya Dwivedi , Andrii Nakryiko Cc: bpf , Alexei Starovoitov , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , "David S. Miller" , Jakub Kicinski , Jesper Dangaard Brouer , Networking References: <20210420193740.124285-1-memxor@gmail.com> <20210420193740.124285-4-memxor@gmail.com> <20210421195643.tduqyyfr5xubxfgn@apollo> <87o8e7gypg.fsf@toke.dk> From: Daniel Borkmann Message-ID: <67563477-49b4-a475-7002-a27f30c1d3e4@iogearbox.net> Date: Thu, 22 Apr 2021 00:41:38 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <87o8e7gypg.fsf@toke.dk> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-Authenticated-Sender: daniel@iogearbox.net X-Virus-Scanned: Clear (ClamAV 0.102.4/26147/Wed Apr 21 13:06:05 2021) Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On 4/21/21 10:38 PM, Toke Høiland-Jørgensen wrote: > Kumar Kartikeya Dwivedi writes: > >> On Wed, Apr 21, 2021 at 11:54:18PM IST, Andrii Nakryiko wrote: >>> On Tue, Apr 20, 2021 at 12:37 PM Kumar Kartikeya Dwivedi >>> wrote: >>>> >>>> This adds some basic tests for the low level bpf_tc_* API. >>>> >>>> Reviewed-by: Toke Høiland-Jørgensen >>>> Signed-off-by: Kumar Kartikeya Dwivedi >>>> --- >>>> .../selftests/bpf/prog_tests/test_tc_bpf.c | 169 ++++++++++++++++++ >>>> .../selftests/bpf/progs/test_tc_bpf_kern.c | 12 ++ >>>> 2 files changed, 181 insertions(+) >>>> create mode 100644 tools/testing/selftests/bpf/prog_tests/test_tc_bpf.c >>> >>> we normally don't call prog_test's files with "test_" prefix, it can >>> be just tc_bpf.c (or just tc.c) >>> >> >> Ok, will rename. >> >>>> create mode 100644 tools/testing/selftests/bpf/progs/test_tc_bpf_kern.c >>> >>> we also don't typically call BPF source code files with _kern suffix, >>> just test_tc_bpf.c would be more in line with most common case >>> >> >> Will rename. >> >>>> >>>> diff --git a/tools/testing/selftests/bpf/prog_tests/test_tc_bpf.c b/tools/testing/selftests/bpf/prog_tests/test_tc_bpf.c >>>> new file mode 100644 >>>> index 000000000000..563a3944553c >>>> --- /dev/null >>>> +++ b/tools/testing/selftests/bpf/prog_tests/test_tc_bpf.c >>>> @@ -0,0 +1,169 @@ >>>> +// SPDX-License-Identifier: GPL-2.0 >>>> + >>>> +#include >>>> +#include >>>> +#include >>>> +#include >>>> +#include >>>> +#include >>>> +#include >>>> +#include >>>> +#include >>>> + >>>> +#define LO_IFINDEX 1 >>>> + >>>> +static int test_tc_internal(int fd, __u32 parent_id) >>>> +{ >>>> + DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts, .handle = 1, .priority = 10, >>>> + .class_id = TC_H_MAKE(1UL << 16, 1)); >>>> + struct bpf_tc_attach_id id = {}; >>>> + struct bpf_tc_info info = {}; >>>> + int ret; >>>> + >>>> + ret = bpf_tc_attach(fd, LO_IFINDEX, parent_id, &opts, &id); >>>> + if (!ASSERT_EQ(ret, 0, "bpf_tc_attach")) >>>> + return ret; >>>> + >>>> + ret = bpf_tc_get_info(LO_IFINDEX, parent_id, &id, &info); >>>> + if (!ASSERT_EQ(ret, 0, "bpf_tc_get_info")) >>>> + goto end; >>>> + >>>> + if (!ASSERT_EQ(info.id.handle, id.handle, "handle mismatch") || >>>> + !ASSERT_EQ(info.id.priority, id.priority, "priority mismatch") || >>>> + !ASSERT_EQ(info.id.handle, 1, "handle incorrect") || >>>> + !ASSERT_EQ(info.chain_index, 0, "chain_index incorrect") || >>>> + !ASSERT_EQ(info.id.priority, 10, "priority incorrect") || >>>> + !ASSERT_EQ(info.class_id, TC_H_MAKE(1UL << 16, 1), >>>> + "class_id incorrect") || >>>> + !ASSERT_EQ(info.protocol, ETH_P_ALL, "protocol incorrect")) >>>> + goto end; >>>> + >>>> + opts.replace = true; >>>> + ret = bpf_tc_attach(fd, LO_IFINDEX, parent_id, &opts, &id); >>>> + if (!ASSERT_EQ(ret, 0, "bpf_tc_attach in replace mode")) >>>> + return ret; >>>> + >>>> + /* Demonstrate changing attributes */ >>>> + opts.class_id = TC_H_MAKE(1UL << 16, 2); >>>> + >>>> + ret = bpf_tc_attach(fd, LO_IFINDEX, parent_id, &opts, &id); >>>> + if (!ASSERT_EQ(ret, 0, "bpf_tc attach in replace mode")) >>>> + goto end; >>>> + >>>> + ret = bpf_tc_get_info(LO_IFINDEX, parent_id, &id, &info); >>>> + if (!ASSERT_EQ(ret, 0, "bpf_tc_get_info")) >>>> + goto end; >>>> + >>>> + if (!ASSERT_EQ(info.class_id, TC_H_MAKE(1UL << 16, 2), >>>> + "class_id incorrect after replace")) >>>> + goto end; >>>> + if (!ASSERT_EQ(info.bpf_flags & TCA_BPF_FLAG_ACT_DIRECT, 1, >>>> + "direct action mode not set")) >>>> + goto end; >>>> + >>>> +end: >>>> + ret = bpf_tc_detach(LO_IFINDEX, parent_id, &id); >>>> + ASSERT_EQ(ret, 0, "detach failed"); >>>> + return ret; >>>> +} >>>> + >>>> +int test_tc_info(int fd) >>>> +{ >>>> + DECLARE_LIBBPF_OPTS(bpf_tc_opts, opts, .handle = 1, .priority = 10, >>>> + .class_id = TC_H_MAKE(1UL << 16, 1)); >>>> + struct bpf_tc_attach_id id = {}, old; >>>> + struct bpf_tc_info info = {}; >>>> + int ret; >>>> + >>>> + ret = bpf_tc_attach(fd, LO_IFINDEX, BPF_TC_CLSACT_INGRESS, &opts, &id); >>>> + if (!ASSERT_EQ(ret, 0, "bpf_tc_attach")) >>>> + return ret; >>>> + old = id; >>>> + >>>> + ret = bpf_tc_get_info(LO_IFINDEX, BPF_TC_CLSACT_INGRESS, &id, &info); >>>> + if (!ASSERT_EQ(ret, 0, "bpf_tc_get_info")) >>>> + goto end_old; >>>> + >>>> + if (!ASSERT_EQ(info.id.handle, id.handle, "handle mismatch") || >>>> + !ASSERT_EQ(info.id.priority, id.priority, "priority mismatch") || >>>> + !ASSERT_EQ(info.id.handle, 1, "handle incorrect") || >>>> + !ASSERT_EQ(info.chain_index, 0, "chain_index incorrect") || >>>> + !ASSERT_EQ(info.id.priority, 10, "priority incorrect") || >>>> + !ASSERT_EQ(info.class_id, TC_H_MAKE(1UL << 16, 1), >>>> + "class_id incorrect") || >>>> + !ASSERT_EQ(info.protocol, ETH_P_ALL, "protocol incorrect")) >>>> + goto end_old; >>>> + >>>> + /* choose a priority */ >>>> + opts.priority = 0; >>>> + ret = bpf_tc_attach(fd, LO_IFINDEX, BPF_TC_CLSACT_INGRESS, &opts, &id); >>>> + if (!ASSERT_EQ(ret, 0, "bpf_tc_attach")) >>>> + goto end_old; >>>> + >>>> + ret = bpf_tc_get_info(LO_IFINDEX, BPF_TC_CLSACT_INGRESS, &id, &info); >>>> + if (!ASSERT_EQ(ret, 0, "bpf_tc_get_info")) >>>> + goto end; >>>> + >>>> + if (!ASSERT_NEQ(id.priority, old.priority, "filter priority mismatch")) >>>> + goto end; >>>> + if (!ASSERT_EQ(info.id.priority, id.priority, "priority mismatch")) >>>> + goto end; >>>> + >>>> +end: >>>> + ret = bpf_tc_detach(LO_IFINDEX, BPF_TC_CLSACT_INGRESS, &id); >>>> + ASSERT_EQ(ret, 0, "detach failed"); >>>> +end_old: >>>> + ret = bpf_tc_detach(LO_IFINDEX, BPF_TC_CLSACT_INGRESS, &old); >>>> + ASSERT_EQ(ret, 0, "detach failed"); >>>> + return ret; >>>> +} >>>> + >>>> +void test_test_tc_bpf(void) >>> >>> test_test_ tautology, drop one test? >>> >> >> Ok. >> >>>> +{ >>>> + const char *file = "./test_tc_bpf_kern.o"; >>> >>> please use BPF skeleton instead, see lots of other selftests doing >>> that already. You won't even need find_program_by_{name,title}, among >>> other things. >>> >> >> Sounds good, will change. >> >>>> + struct bpf_program *clsp; >>>> + struct bpf_object *obj; >>>> + int cls_fd, ret; >>>> + >>>> + obj = bpf_object__open(file); >>>> + if (!ASSERT_OK_PTR(obj, "bpf_object__open")) >>>> + return; >>>> + >>>> + clsp = bpf_object__find_program_by_title(obj, "classifier"); >>>> + if (!ASSERT_OK_PTR(clsp, "bpf_object__find_program_by_title")) >>>> + goto end; >>>> + >>>> + ret = bpf_object__load(obj); >>>> + if (!ASSERT_EQ(ret, 0, "bpf_object__load")) >>>> + goto end; >>>> + >>>> + cls_fd = bpf_program__fd(clsp); >>>> + >>>> + system("tc qdisc del dev lo clsact"); >>> >>> can this fail? also why is this necessary? it's still not possible to >> >> This is just removing any existing clsact qdisc since it will be setup by the >> attach call, which is again removed later (where we do check if it fails, if it >> does clsact qdisc was not setup, and something was wrong in that it returned 0 >> when the attach point was one of the clsact hooks). >> >> We don't care about failure initially, since if it isn't present we'd just move >> on to running the test. >> >>> do anything with only libbpf APIs? >> >> I don't think so, I can do the qdisc teardown using netlink in the selftest, >> but that would mean duplicating a lot of code. I think expecting tc to be >> present on the system is a reasonable assumption for this test. > > So this stems from the fact that bpf_tc_detach() doesn't clean up the > clsact qdisc that is added by bpf_tc_attach(). I think we should fix > this. I was wondering whether it would make sense to add a bpf_tc_ctx_init() and bpf_tc_ctx_destroy() API which would auto-create the sch_clsact qdisc, plus provide a 'handle' for bpf_tc_attach() and bpf_tc_detach(), and for the other one, it would delete the qdisc. Otoh, if an empty sch_clsact obj is sitting around while not being great (given minor effect on fast-path), it also doesn't harm /overly/ much. Maybe a /poor/ analogy could be that if you open a v6 socket, it pulls in the ipv6 module, but also doesn't remove it when you close() it. Anyway, but for the test itself, given you can define prio etc, I don't think it would even need the system() call? Thanks, Daniel