Commit d42d1cc4 authored by YiFei Zhu's avatar YiFei Zhu Committed by Alexei Starovoitov
Browse files

selftests/bpf: Test load and dump metadata with btftool and skel 



This is a simple test to check that loading and dumping metadata
in btftool works, whether or not metadata contents are used by the
program.

A C test is also added to make sure the skeleton code can read the
metadata values.

Signed-off-by: default avatarYiFei Zhu <zhuyifei@google.com>
Signed-off-by: default avatarStanislav Fomichev <sdf@google.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarAndrii Nakryiko <andriin@fb.com>
Cc: YiFei Zhu <zhuyifei1999@gmail.com>
Link: https://lore.kernel.org/bpf/20200915234543.3220146-6-sdf@google.com
parent aff52e68

tools/testing/selftests/bpf/Makefile

+2 −1
Original line number Diff line number Diff line
@@ -68,7 +68,8 @@ TEST_PROGS := test_kmod.sh \ 
	test_tc_edt.sh \

	test_xdping.sh \

	test_bpftool_build.sh \

	test_bpftool.sh

	test_bpftool.sh \

	test_bpftool_metadata.sh \



TEST_PROGS_EXTENDED := with_addr.sh \

	with_tunnels.sh \

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

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+141 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only



/*

 * Copyright 2020 Google LLC.

 */



#include <test_progs.h>

#include <cgroup_helpers.h>

#include <network_helpers.h>



#include "metadata_unused.skel.h"

#include "metadata_used.skel.h"



static int duration;



static int prog_holds_map(int prog_fd, int map_fd)

{

	struct bpf_prog_info prog_info = {};

	struct bpf_prog_info map_info = {};

	__u32 prog_info_len;

	__u32 map_info_len;

	__u32 *map_ids;

	int nr_maps;

	int ret;

	int i;



	map_info_len = sizeof(map_info);

	ret = bpf_obj_get_info_by_fd(map_fd, &map_info, &map_info_len);

	if (ret)

		return -errno;



	prog_info_len = sizeof(prog_info);

	ret = bpf_obj_get_info_by_fd(prog_fd, &prog_info, &prog_info_len);

	if (ret)

		return -errno;



	map_ids = calloc(prog_info.nr_map_ids, sizeof(__u32));

	if (!map_ids)

		return -ENOMEM;



	nr_maps = prog_info.nr_map_ids;

	memset(&prog_info, 0, sizeof(prog_info));

	prog_info.nr_map_ids = nr_maps;

	prog_info.map_ids = ptr_to_u64(map_ids);

	prog_info_len = sizeof(prog_info);



	ret = bpf_obj_get_info_by_fd(prog_fd, &prog_info, &prog_info_len);

	if (ret) {

		ret = -errno;

		goto free_map_ids;

	}



	ret = -ENOENT;

	for (i = 0; i < prog_info.nr_map_ids; i++) {

		if (map_ids[i] == map_info.id) {

			ret = 0;

			break;

		}

	}



free_map_ids:

	free(map_ids);

	return ret;

}



static void test_metadata_unused(void)

{

	struct metadata_unused *obj;

	int err;



	obj = metadata_unused__open_and_load();

	if (CHECK(!obj, "skel-load", "errno %d", errno))

		return;



	err = prog_holds_map(bpf_program__fd(obj->progs.prog),

			     bpf_map__fd(obj->maps.rodata));

	if (CHECK(err, "prog-holds-rodata", "errno: %d", err))

		return;



	/* Assert that we can access the metadata in skel and the values are

	 * what we expect.

	 */

	if (CHECK(strncmp(obj->rodata->bpf_metadata_a, "foo",

			  sizeof(obj->rodata->bpf_metadata_a)),

		  "bpf_metadata_a", "expected \"foo\", value differ"))

		goto close_bpf_object;

	if (CHECK(obj->rodata->bpf_metadata_b != 1, "bpf_metadata_b",

		  "expected 1, got %d", obj->rodata->bpf_metadata_b))

		goto close_bpf_object;



	/* Assert that binding metadata map to prog again succeeds. */

	err = bpf_prog_bind_map(bpf_program__fd(obj->progs.prog),

				bpf_map__fd(obj->maps.rodata), NULL);

	CHECK(err, "rebind_map", "errno %d, expected 0", errno);



close_bpf_object:

	metadata_unused__destroy(obj);

}



static void test_metadata_used(void)

{

	struct metadata_used *obj;

	int err;



	obj = metadata_used__open_and_load();

	if (CHECK(!obj, "skel-load", "errno %d", errno))

		return;



	err = prog_holds_map(bpf_program__fd(obj->progs.prog),

			     bpf_map__fd(obj->maps.rodata));

	if (CHECK(err, "prog-holds-rodata", "errno: %d", err))

		return;



	/* Assert that we can access the metadata in skel and the values are

	 * what we expect.

	 */

	if (CHECK(strncmp(obj->rodata->bpf_metadata_a, "bar",

			  sizeof(obj->rodata->bpf_metadata_a)),

		  "metadata_a", "expected \"bar\", value differ"))

		goto close_bpf_object;

	if (CHECK(obj->rodata->bpf_metadata_b != 2, "metadata_b",

		  "expected 2, got %d", obj->rodata->bpf_metadata_b))

		goto close_bpf_object;



	/* Assert that binding metadata map to prog again succeeds. */

	err = bpf_prog_bind_map(bpf_program__fd(obj->progs.prog),

				bpf_map__fd(obj->maps.rodata), NULL);

	CHECK(err, "rebind_map", "errno %d, expected 0", errno);



close_bpf_object:

	metadata_used__destroy(obj);

}



void test_metadata(void)

{

	if (test__start_subtest("unused"))

		test_metadata_unused();



	if (test__start_subtest("used"))

		test_metadata_used();

}

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

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+15 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only



#include <linux/bpf.h>

#include <bpf/bpf_helpers.h>



volatile const char bpf_metadata_a[] SEC(".rodata") = "foo";

volatile const int bpf_metadata_b SEC(".rodata") = 1;



SEC("cgroup_skb/egress")

int prog(struct xdp_md *ctx)

{

	return 0;

}



char _license[] SEC("license") = "GPL";

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

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+15 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only



#include <linux/bpf.h>

#include <bpf/bpf_helpers.h>



volatile const char bpf_metadata_a[] SEC(".rodata") = "bar";

volatile const int bpf_metadata_b SEC(".rodata") = 2;



SEC("cgroup_skb/egress")

int prog(struct xdp_md *ctx)

{

	return bpf_metadata_b ? 1 : 0;

}



char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/test_bpftool_metadata.sh

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Original line number Diff line number Diff line 
#!/bin/sh

# SPDX-License-Identifier: GPL-2.0



# Kselftest framework requirement - SKIP code is 4.

ksft_skip=4



TESTNAME=bpftool_metadata

BPF_FS=$(awk '$3 == "bpf" {print $2; exit}' /proc/mounts)

BPF_DIR=$BPF_FS/test_$TESTNAME



_cleanup()

{

	set +e

	rm -rf $BPF_DIR 2> /dev/null

}



cleanup_skip()

{

	echo "selftests: $TESTNAME [SKIP]"

	_cleanup



	exit $ksft_skip

}



cleanup()

{

	if [ "$?" = 0 ]; then

		echo "selftests: $TESTNAME [PASS]"

	else

		echo "selftests: $TESTNAME [FAILED]"

	fi

	_cleanup

}



if [ $(id -u) -ne 0 ]; then

	echo "selftests: $TESTNAME [SKIP] Need root privileges"

	exit $ksft_skip

fi



if [ -z "$BPF_FS" ]; then

	echo "selftests: $TESTNAME [SKIP] Could not run test without bpffs mounted"

	exit $ksft_skip

fi



if ! bpftool version > /dev/null 2>&1; then

	echo "selftests: $TESTNAME [SKIP] Could not run test without bpftool"

	exit $ksft_skip

fi



set -e



trap cleanup_skip EXIT



mkdir $BPF_DIR



trap cleanup EXIT



bpftool prog load metadata_unused.o $BPF_DIR/unused



METADATA_PLAIN="$(bpftool prog)"

echo "$METADATA_PLAIN" | grep 'a = "foo"' > /dev/null

echo "$METADATA_PLAIN" | grep 'b = 1' > /dev/null



bpftool prog --json | grep '"metadata":{"a":"foo","b":1}' > /dev/null



bpftool map | grep 'metadata.rodata' > /dev/null



rm $BPF_DIR/unused



bpftool prog load metadata_used.o $BPF_DIR/used



METADATA_PLAIN="$(bpftool prog)"

echo "$METADATA_PLAIN" | grep 'a = "bar"' > /dev/null

echo "$METADATA_PLAIN" | grep 'b = 2' > /dev/null



bpftool prog --json | grep '"metadata":{"a":"bar","b":2}' > /dev/null



bpftool map | grep 'metadata.rodata' > /dev/null



rm $BPF_DIR/used



exit 0