selftest/bpf: Simple test for fentry/fexit (e41074d3) · Commits · 戴 / test

tools/testing/selftests/bpf/prog_tests/kfree_skb.c

+36 −3

Original line number	Diff line number	Diff line
		@@ -60,15 +60,17 @@ void test_kfree_skb(void)
		.file = "./kfree_skb.o",
		};

		struct bpf_link link = NULL, link_fentry = NULL, *link_fexit = NULL;
		struct bpf_map perf_buf_map, global_data;
		struct bpf_program prog, fentry, *fexit;
		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;
		int err, kfree_skb_fd;
		bool passed = false;
		__u32 duration = 0;
		const int zero = 0;
		bool test_ok[2];

		err = bpf_prog_load("./test_pkt_access.o", BPF_PROG_TYPE_SCHED_CLS,
		&obj, &tattr.prog_fd);
		@@ -82,9 +84,28 @@ void test_kfree_skb(void)
		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;
		fentry = bpf_object__find_program_by_title(obj2, "fentry/eth_type_trans");
		if (CHECK(!fentry, "find_prog", "prog eth_type_trans not found\n"))
		goto close_prog;
		fexit = bpf_object__find_program_by_title(obj2, "fexit/eth_type_trans");
		if (CHECK(!fexit, "find_prog", "prog eth_type_trans not found\n"))
		goto close_prog;

		global_data = bpf_object__find_map_by_name(obj2, "kfree_sk.bss");
		if (CHECK(!global_data, "find global data", "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;
		link_fentry = bpf_program__attach_trace(fentry);
		if (CHECK(IS_ERR(link_fentry), "attach fentry", "err %ld\n",
		PTR_ERR(link_fentry)))
		goto close_prog;
		link_fexit = bpf_program__attach_trace(fexit);
		if (CHECK(IS_ERR(link_fexit), "attach fexit", "err %ld\n",
		PTR_ERR(link_fexit)))
		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"))
		@@ -108,14 +129,26 @@ void test_kfree_skb(void)
		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);

		err = bpf_map_lookup_elem(bpf_map__fd(global_data), &zero, test_ok);
		if (CHECK(err, "get_result",
		"failed to get output data: %d\n", err))
		goto close_prog;

		CHECK_FAIL(!test_ok[0] \|\| !test_ok[1]);
		close_prog:
		perf_buffer__free(pb);
		if (!IS_ERR_OR_NULL(link))
		bpf_link__destroy(link);
		if (!IS_ERR_OR_NULL(link_fentry))
		bpf_link__destroy(link_fentry);
		if (!IS_ERR_OR_NULL(link_fexit))
		bpf_link__destroy(link_fexit);
		bpf_object__close(obj);
		bpf_object__close(obj2);
		}

tools/testing/selftests/bpf/progs/kfree_skb.c

+52 −0

Original line number	Diff line number	Diff line
		// SPDX-License-Identifier: GPL-2.0
		// Copyright (c) 2019 Facebook
		#include <linux/bpf.h>
		#include <stdbool.h>
		#include "bpf_helpers.h"
		#include "bpf_endian.h"

		@@ -116,3 +117,54 @@ int trace_kfree_skb(struct trace_kfree_skb *ctx)
		&meta, sizeof(meta));
		return 0;
		}

		static volatile struct {
		bool fentry_test_ok;
		bool fexit_test_ok;
		} result;

		struct eth_type_trans_args {
		struct sk_buff *skb;
		struct net_device *dev;
		unsigned short protocol; /* return value available to fexit progs */
		};

		SEC("fentry/eth_type_trans")
		int fentry_eth_type_trans(struct eth_type_trans_args *ctx)
		{
		struct sk_buff *skb = ctx->skb;
		struct net_device *dev = ctx->dev;
		int len, ifindex;

		__builtin_preserve_access_index(({
		len = skb->len;
		ifindex = dev->ifindex;
		}));

		/* fentry sees full packet including L2 header */
		if (len != 74 \|\| ifindex != 1)
		return 0;
		result.fentry_test_ok = true;
		return 0;
		}

		SEC("fexit/eth_type_trans")
		int fexit_eth_type_trans(struct eth_type_trans_args *ctx)
		{
		struct sk_buff *skb = ctx->skb;
		struct net_device *dev = ctx->dev;
		int len, ifindex;

		__builtin_preserve_access_index(({
		len = skb->len;
		ifindex = dev->ifindex;
		}));

		/* fexit sees packet without L2 header that eth_type_trans should have
		* consumed.
		*/
		if (len != 60 \|\| ctx->protocol != bpf_htons(0x86dd) \|\| ifindex != 1)
		return 0;
		result.fexit_test_ok = true;
		return 0;
		}

Admin message