From patchwork Wed Oct 16 03:25:05 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexei Starovoitov X-Patchwork-Id: 1177531 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: incoming-bpf@patchwork.ozlabs.org Delivered-To: patchwork-incoming-bpf@bilbo.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=bpf-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 46tHk906FGz9sPF for ; Wed, 16 Oct 2019 14:25:37 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390985AbfJPDZf (ORCPT ); Tue, 15 Oct 2019 23:25:35 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:40294 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2390974AbfJPDZb (ORCPT ); Tue, 15 Oct 2019 23:25:31 -0400 Received: from pps.filterd (m0089730.ppops.net [127.0.0.1]) by m0089730.ppops.net (8.16.0.42/8.16.0.42) with SMTP id x9G3Ow9b003719 for ; Tue, 15 Oct 2019 20:25:30 -0700 Received: from maileast.thefacebook.com ([163.114.130.16]) by m0089730.ppops.net with ESMTP id 2vnccac5fy-4 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 15 Oct 2019 20:25:30 -0700 Received: from 2401:db00:2050:5102:face:0:3b:0 (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::4) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Tue, 15 Oct 2019 20:25:29 -0700 Received: by devbig007.ftw2.facebook.com (Postfix, from userid 572438) id 2644B760F32; Tue, 15 Oct 2019 20:25:29 -0700 (PDT) Smtp-Origin-Hostprefix: devbig From: Alexei Starovoitov Smtp-Origin-Hostname: devbig007.ftw2.facebook.com To: CC: , , , , Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH v3 bpf-next 11/11] selftests/bpf: add kfree_skb raw_tp test Date: Tue, 15 Oct 2019 20:25:05 -0700 Message-ID: <20191016032505.2089704-12-ast@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20191016032505.2089704-1-ast@kernel.org> References: <20191016032505.2089704-1-ast@kernel.org> X-FB-Internal: Safe MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95,1.0.8 definitions=2019-10-16_01:2019-10-15,2019-10-16 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 clxscore=1015 bulkscore=0 priorityscore=1501 lowpriorityscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 malwarescore=0 suspectscore=4 phishscore=0 impostorscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1908290000 definitions=main-1910160029 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Load basic cls_bpf program. Load raw_tracepoint program and attach to kfree_skb raw tracepoint. Trigger cls_bpf via prog_test_run. At the end of test_run kernel will call kfree_skb which will trigger trace_kfree_skb tracepoint. Which will call our raw_tracepoint program. Which will take that skb and will dump it into perf ring buffer. Check that user space received correct packet. Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko --- .../selftests/bpf/prog_tests/kfree_skb.c | 89 +++++++++++++++ tools/testing/selftests/bpf/progs/kfree_skb.c | 103 ++++++++++++++++++ 2 files changed, 192 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/kfree_skb.c create mode 100644 tools/testing/selftests/bpf/progs/kfree_skb.c diff --git a/tools/testing/selftests/bpf/prog_tests/kfree_skb.c b/tools/testing/selftests/bpf/prog_tests/kfree_skb.c new file mode 100644 index 000000000000..430b50de1583 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/kfree_skb.c @@ -0,0 +1,89 @@ +// SPDX-License-Identifier: GPL-2.0 +#include + +static void on_sample(void *ctx, int cpu, void *data, __u32 size) +{ + int ifindex = *(int *)data, duration = 0; + struct ipv6_packet *pkt_v6 = data + 4; + + if (ifindex != 1) + /* spurious kfree_skb not on loopback device */ + return; + if (CHECK(size != 76, "check_size", "size %u != 76\n", size)) + return; + if (CHECK(pkt_v6->eth.h_proto != 0xdd86, "check_eth", + "h_proto %x\n", pkt_v6->eth.h_proto)) + return; + if (CHECK(pkt_v6->iph.nexthdr != 6, "check_ip", + "iph.nexthdr %x\n", pkt_v6->iph.nexthdr)) + return; + if (CHECK(pkt_v6->tcp.doff != 5, "check_tcp", + "tcp.doff %x\n", pkt_v6->tcp.doff)) + return; + + *(bool *)ctx = true; +} + +void test_kfree_skb(void) +{ + struct bpf_prog_load_attr attr = { + .file = "./kfree_skb.o", + }; + + struct bpf_object *obj, *obj2 = NULL; + struct perf_buffer_opts pb_opts = {}; + struct perf_buffer *pb = NULL; + struct bpf_link *link = NULL; + struct bpf_map *perf_buf_map; + struct bpf_program *prog; + __u32 duration, retval; + int err, pkt_fd, kfree_skb_fd; + bool passed = false; + + err = bpf_prog_load("./test_pkt_access.o", BPF_PROG_TYPE_SCHED_CLS, &obj, &pkt_fd); + if (CHECK(err, "prog_load sched cls", "err %d errno %d\n", err, errno)) + return; + + err = bpf_prog_load_xattr(&attr, &obj2, &kfree_skb_fd); + if (CHECK(err, "prog_load raw tp", "err %d errno %d\n", err, errno)) + goto close_prog; + + prog = bpf_object__find_program_by_title(obj2, "tp_btf/kfree_skb"); + if (CHECK(!prog, "find_prog", "prog kfree_skb not found\n")) + goto close_prog; + link = bpf_program__attach_raw_tracepoint(prog, NULL); + if (CHECK(IS_ERR(link), "attach_raw_tp", "err %ld\n", PTR_ERR(link))) + goto close_prog; + + perf_buf_map = bpf_object__find_map_by_name(obj2, "perf_buf_map"); + if (CHECK(!perf_buf_map, "find_perf_buf_map", "not found\n")) + goto close_prog; + + /* set up perf buffer */ + pb_opts.sample_cb = on_sample; + pb_opts.ctx = &passed; + pb = perf_buffer__new(bpf_map__fd(perf_buf_map), 1, &pb_opts); + if (CHECK(IS_ERR(pb), "perf_buf__new", "err %ld\n", PTR_ERR(pb))) + goto close_prog; + + err = bpf_prog_test_run(pkt_fd, 1, &pkt_v6, sizeof(pkt_v6), + NULL, NULL, &retval, &duration); + CHECK(err || retval, "ipv6", + "err %d errno %d retval %d duration %d\n", + err, errno, retval, duration); + + /* read perf buffer */ + err = perf_buffer__poll(pb, 100); + if (CHECK(err < 0, "perf_buffer__poll", "err %d\n", err)) + goto close_prog; + /* make sure kfree_skb program was triggered + * and it sent expected skb into ring buffer + */ + CHECK_FAIL(!passed); +close_prog: + perf_buffer__free(pb); + if (!IS_ERR_OR_NULL(link)) + bpf_link__destroy(link); + bpf_object__close(obj); + bpf_object__close(obj2); +} diff --git a/tools/testing/selftests/bpf/progs/kfree_skb.c b/tools/testing/selftests/bpf/progs/kfree_skb.c new file mode 100644 index 000000000000..89af8a921ee4 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/kfree_skb.c @@ -0,0 +1,103 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2019 Facebook +#include +#include "bpf_helpers.h" +#include "bpf_endian.h" + +char _license[] SEC("license") = "GPL"; +struct { + __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY); + __uint(key_size, sizeof(int)); + __uint(value_size, sizeof(int)); +} perf_buf_map SEC(".maps"); + +#define _(P) (__builtin_preserve_access_index(P)) + +/* define few struct-s that bpf program needs to access */ +struct callback_head { + struct callback_head *next; + void (*func)(struct callback_head *head); +}; +struct dev_ifalias { + struct callback_head rcuhead; +}; + +struct net_device /* same as kernel's struct net_device */ { + int ifindex; + struct dev_ifalias *ifalias; +}; + +typedef struct { + int counter; +} atomic_t; +typedef struct refcount_struct { + atomic_t refs; +} refcount_t; + +struct sk_buff { + /* field names and sizes should match to those in the kernel */ + unsigned int len, data_len; + __u16 mac_len, hdr_len, queue_mapping; + struct net_device *dev; + /* order of the fields doesn't matter */ + refcount_t users; + unsigned char *data; + char __pkt_type_offset[0]; +}; + +/* copy arguments from + * include/trace/events/skb.h: + * TRACE_EVENT(kfree_skb, + * TP_PROTO(struct sk_buff *skb, void *location), + * + * into struct below: + */ +struct trace_kfree_skb { + struct sk_buff *skb; + void *location; +}; + +SEC("tp_btf/kfree_skb") +int trace_kfree_skb(struct trace_kfree_skb *ctx) +{ + struct sk_buff *skb = ctx->skb; + struct net_device *dev; + int ifindex; + struct callback_head *ptr; + void *func; + int users; + unsigned char *data; + unsigned short pkt_data; + char pkt_type; + + __builtin_preserve_access_index(({ + users = skb->users.refs.counter; + data = skb->data; + dev = skb->dev; + ifindex = dev->ifindex; + ptr = dev->ifalias->rcuhead.next; + func = ptr->func; + })); + + bpf_probe_read(&pkt_type, sizeof(pkt_type), _(&skb->__pkt_type_offset)); + pkt_type &= 7; + + /* read eth proto */ + bpf_probe_read(&pkt_data, sizeof(pkt_data), data + 12); + + bpf_printk("rcuhead.next %llx func %llx\n", ptr, func); + bpf_printk("skb->len %d users %d pkt_type %x\n", + _(skb->len), users, pkt_type); + bpf_printk("skb->queue_mapping %d\n", _(skb->queue_mapping)); + bpf_printk("dev->ifindex %d data %llx pkt_data %x\n", + ifindex, data, pkt_data); + + if (users != 1 || pkt_data != bpf_htons(0x86dd) || ifindex != 1) + /* raw tp ignores return value */ + return 0; + + /* send first 72 byte of the packet to user space */ + bpf_skb_output(skb, &perf_buf_map, (72ull << 32) | BPF_F_CURRENT_CPU, + &ifindex, sizeof(ifindex)); + return 0; +}