bpf_loop.c

// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2021 Facebook */

#include <test_progs.h>
#include <network_helpers.h>
#include "bpf_loop.skel.h"

static void check_nr_loops(struct bpf_loop *skel)
{
	struct bpf_link *link;

	link = bpf_program__attach(skel->progs.test_prog);
	if (!ASSERT_OK_PTR(link, "link"))
		return;

	/* test 0 loops */
	skel->bss->nr_loops = 0;

	usleep(1);

	ASSERT_EQ(skel->bss->nr_loops_returned, skel->bss->nr_loops,
		  "0 loops");

	/* test 500 loops */
	skel->bss->nr_loops = 500;

	usleep(1);

	ASSERT_EQ(skel->bss->nr_loops_returned, skel->bss->nr_loops,
		  "500 loops");
	ASSERT_EQ(skel->bss->g_output, (500 * 499) / 2, "g_output");

	/* test exceeding the max limit */
	skel->bss->nr_loops = -1;

	usleep(1);

	ASSERT_EQ(skel->bss->err, -E2BIG, "over max limit");

	bpf_link__destroy(link);
}

static void check_callback_fn_stop(struct bpf_loop *skel)
{
	struct bpf_link *link;

	link = bpf_program__attach(skel->progs.test_prog);
	if (!ASSERT_OK_PTR(link, "link"))
		return;

	/* testing that loop is stopped when callback_fn returns 1 */
	skel->bss->nr_loops = 400;
	skel->data->stop_index = 50;

	usleep(1);

	ASSERT_EQ(skel->bss->nr_loops_returned, skel->data->stop_index + 1,
		  "nr_loops_returned");
	ASSERT_EQ(skel->bss->g_output, (50 * 49) / 2,
		  "g_output");

	bpf_link__destroy(link);
}

static void check_null_callback_ctx(struct bpf_loop *skel)
{
	struct bpf_link *link;

	/* check that user is able to pass in a null callback_ctx */
	link = bpf_program__attach(skel->progs.prog_null_ctx);
	if (!ASSERT_OK_PTR(link, "link"))
		return;

	skel->bss->nr_loops = 10;

	usleep(1);

	ASSERT_EQ(skel->bss->nr_loops_returned, skel->bss->nr_loops,
		  "nr_loops_returned");

	bpf_link__destroy(link);
}

static void check_invalid_flags(struct bpf_loop *skel)
{
	struct bpf_link *link;

	/* check that passing in non-zero flags returns -EINVAL */
	link = bpf_program__attach(skel->progs.prog_invalid_flags);
	if (!ASSERT_OK_PTR(link, "link"))
		return;

	usleep(1);

	ASSERT_EQ(skel->bss->err, -EINVAL, "err");

	bpf_link__destroy(link);
}

static void check_nested_calls(struct bpf_loop *skel)
{
	__u32 nr_loops = 100, nested_callback_nr_loops = 4;
	struct bpf_link *link;

	/* check that nested calls are supported */
	link = bpf_program__attach(skel->progs.prog_nested_calls);
	if (!ASSERT_OK_PTR(link, "link"))
		return;

	skel->bss->nr_loops = nr_loops;
	skel->bss->nested_callback_nr_loops = nested_callback_nr_loops;

	usleep(1);

	ASSERT_EQ(skel->bss->nr_loops_returned, nr_loops * nested_callback_nr_loops
		  * nested_callback_nr_loops, "nr_loops_returned");
	ASSERT_EQ(skel->bss->g_output, (4 * 3) / 2 * nested_callback_nr_loops
		* nr_loops, "g_output");

	bpf_link__destroy(link);
}

static void check_non_constant_callback(struct bpf_loop *skel)
{
	struct bpf_link *link =
		bpf_program__attach(skel->progs.prog_non_constant_callback);

	if (!ASSERT_OK_PTR(link, "link"))
		return;

	skel->bss->callback_selector = 0x0F;
	usleep(1);
	ASSERT_EQ(skel->bss->g_output, 0x0F, "g_output #1");

	skel->bss->callback_selector = 0xF0;
	usleep(1);
	ASSERT_EQ(skel->bss->g_output, 0xF0, "g_output #2");

	bpf_link__destroy(link);
}

static void check_stack(struct bpf_loop *skel)
{
	struct bpf_link *link = bpf_program__attach(skel->progs.stack_check);
	const int max_key = 12;
	int key;
	int map_fd;

	if (!ASSERT_OK_PTR(link, "link"))
		return;

	map_fd = bpf_map__fd(skel->maps.map1);

	if (!ASSERT_GE(map_fd, 0, "bpf_map__fd"))
		goto out;

	for (key = 1; key <= max_key; ++key) {
		int val = key;
		int err = bpf_map_update_elem(map_fd, &key, &val, BPF_NOEXIST);

		if (!ASSERT_OK(err, "bpf_map_update_elem"))
			goto out;
	}

	usleep(1);

	for (key = 1; key <= max_key; ++key) {
		int val;
		int err = bpf_map_lookup_elem(map_fd, &key, &val);

		if (!ASSERT_OK(err, "bpf_map_lookup_elem"))
			goto out;
		if (!ASSERT_EQ(val, key + 1, "bad value in the map"))
			goto out;
	}

out:
	bpf_link__destroy(link);
}

void test_bpf_loop(void)
{
	struct bpf_loop *skel;

	skel = bpf_loop__open_and_load();
	if (!ASSERT_OK_PTR(skel, "bpf_loop__open_and_load"))
		return;

	skel->bss->pid = getpid();

	if (test__start_subtest("check_nr_loops"))
		check_nr_loops(skel);
	if (test__start_subtest("check_callback_fn_stop"))
		check_callback_fn_stop(skel);
	if (test__start_subtest("check_null_callback_ctx"))
		check_null_callback_ctx(skel);
	if (test__start_subtest("check_invalid_flags"))
		check_invalid_flags(skel);
	if (test__start_subtest("check_nested_calls"))
		check_nested_calls(skel);
	if (test__start_subtest("check_non_constant_callback"))
		check_non_constant_callback(skel);
	if (test__start_subtest("check_stack"))
		check_stack(skel);

	bpf_loop__destroy(skel);
}