selftests/bpf: Add bloom filter map test cases

This patch adds test cases for bpf bloom filter maps. They include tests
checking against invalid operations by userspace, tests for using the
bloom filter map as an inner map, and a bpf program that queries the
bloom filter map for values added by a userspace program.
Signed-off-by: Joanne Koong <joannekoong@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211027234504.30744-4-joannekoong@fb.com

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

+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021 Facebook */
+
+#include <sys/syscall.h>
+#include <test_progs.h>
+#include "bloom_filter_map.skel.h"
+
+static void test_fail_cases(void)
+{
+	struct bpf_create_map_attr xattr = {
+		.name = "bloom_filter_map",
+		.map_type = BPF_MAP_TYPE_BLOOM_FILTER,
+		.max_entries = 100,
+		.value_size = 11,
+	};
+	__u32 value;
+	int fd, err;
+
+	/* Invalid key size */
+	xattr.key_size = 4;
+	fd = bpf_create_map_xattr(&xattr);
+	if (!ASSERT_LT(fd, 0, "bpf_create_map bloom filter invalid key size"))
+		close(fd);
+	xattr.key_size = 0;
+
+	/* Invalid value size */
+	xattr.value_size = 0;
+	fd = bpf_create_map_xattr(&xattr);
+	if (!ASSERT_LT(fd, 0, "bpf_create_map bloom filter invalid value size 0"))
+		close(fd);
+	xattr.value_size = 11;
+
+	/* Invalid max entries size */
+	xattr.max_entries = 0;
+	fd = bpf_create_map_xattr(&xattr);
+	if (!ASSERT_LT(fd, 0, "bpf_create_map bloom filter invalid max entries size"))
+		close(fd);
+	xattr.max_entries = 100;
+
+	/* Bloom filter maps do not support BPF_F_NO_PREALLOC */
+	xattr.map_flags = BPF_F_NO_PREALLOC;
+	fd = bpf_create_map_xattr(&xattr);
+	if (!ASSERT_LT(fd, 0, "bpf_create_map bloom filter invalid flags"))
+		close(fd);
+	xattr.map_flags = 0;
+
+	fd = bpf_create_map_xattr(&xattr);
+	if (!ASSERT_GE(fd, 0, "bpf_create_map bloom filter"))
+		return;
+
+	/* Test invalid flags */
+	err = bpf_map_update_elem(fd, NULL, &value, -1);
+	ASSERT_EQ(err, -EINVAL, "bpf_map_update_elem bloom filter invalid flags");
+
+	err = bpf_map_update_elem(fd, NULL, &value, BPF_EXIST);
+	ASSERT_EQ(err, -EINVAL, "bpf_map_update_elem bloom filter invalid flags");
+
+	err = bpf_map_update_elem(fd, NULL, &value, BPF_F_LOCK);
+	ASSERT_EQ(err, -EINVAL, "bpf_map_update_elem bloom filter invalid flags");
+
+	err = bpf_map_update_elem(fd, NULL, &value, BPF_NOEXIST);
+	ASSERT_EQ(err, -EINVAL, "bpf_map_update_elem bloom filter invalid flags");
+
+	err = bpf_map_update_elem(fd, NULL, &value, 10000);
+	ASSERT_EQ(err, -EINVAL, "bpf_map_update_elem bloom filter invalid flags");
+
+	close(fd);
+}
+
+static void check_bloom(struct bloom_filter_map *skel)
+{
+	struct bpf_link *link;
+
+	link = bpf_program__attach(skel->progs.check_bloom);
+	if (!ASSERT_OK_PTR(link, "link"))
+		return;
+
+	syscall(SYS_getpgid);
+
+	ASSERT_EQ(skel->bss->error, 0, "error");
+
+	bpf_link__destroy(link);
+}
+
+static void test_inner_map(struct bloom_filter_map *skel, const __u32 *rand_vals,
+			   __u32 nr_rand_vals)
+{
+	int outer_map_fd, inner_map_fd, err, i, key = 0;
+	struct bpf_create_map_attr xattr = {
+		.name = "bloom_filter_inner_map",
+		.map_type = BPF_MAP_TYPE_BLOOM_FILTER,
+		.value_size = sizeof(__u32),
+		.max_entries = nr_rand_vals,
+	};
+	struct bpf_link *link;
+
+	/* Create a bloom filter map that will be used as the inner map */
+	inner_map_fd = bpf_create_map_xattr(&xattr);
+	if (!ASSERT_GE(inner_map_fd, 0, "bpf_create_map bloom filter inner map"))
+		return;
+
+	for (i = 0; i < nr_rand_vals; i++) {
+		err = bpf_map_update_elem(inner_map_fd, NULL, rand_vals + i, BPF_ANY);
+		if (!ASSERT_OK(err, "Add random value to inner_map_fd"))
+			goto done;
+	}
+
+	/* Add the bloom filter map to the outer map */
+	outer_map_fd = bpf_map__fd(skel->maps.outer_map);
+	err = bpf_map_update_elem(outer_map_fd, &key, &inner_map_fd, BPF_ANY);
+	if (!ASSERT_OK(err, "Add bloom filter map to outer map"))
+		goto done;
+
+	/* Attach the bloom_filter_inner_map prog */
+	link = bpf_program__attach(skel->progs.inner_map);
+	if (!ASSERT_OK_PTR(link, "link"))
+		goto delete_inner_map;
+
+	syscall(SYS_getpgid);
+
+	ASSERT_EQ(skel->bss->error, 0, "error");
+
+	bpf_link__destroy(link);
+
+delete_inner_map:
+	/* Ensure the inner bloom filter map can be deleted */
+	err = bpf_map_delete_elem(outer_map_fd, &key);
+	ASSERT_OK(err, "Delete inner bloom filter map");
+
+done:
+	close(inner_map_fd);
+}
+
+static int setup_progs(struct bloom_filter_map **out_skel, __u32 **out_rand_vals,
+		       __u32 *out_nr_rand_vals)
+{
+	struct bloom_filter_map *skel;
+	int random_data_fd, bloom_fd;
+	__u32 *rand_vals = NULL;
+	__u32 map_size, val;
+	int err, i;
+
+	/* Set up a bloom filter map skeleton */
+	skel = bloom_filter_map__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "bloom_filter_map__open_and_load"))
+		return -EINVAL;
+
+	/* Set up rand_vals */
+	map_size = bpf_map__max_entries(skel->maps.map_random_data);
+	rand_vals = malloc(sizeof(*rand_vals) * map_size);
+	if (!rand_vals) {
+		err = -ENOMEM;
+		goto error;
+	}
+
+	/* Generate random values and populate both skeletons */
+	random_data_fd = bpf_map__fd(skel->maps.map_random_data);
+	bloom_fd = bpf_map__fd(skel->maps.map_bloom);
+	for (i = 0; i < map_size; i++) {
+		val = rand();
+
+		err = bpf_map_update_elem(random_data_fd, &i, &val, BPF_ANY);
+		if (!ASSERT_OK(err, "Add random value to map_random_data"))
+			goto error;
+
+		err = bpf_map_update_elem(bloom_fd, NULL, &val, BPF_ANY);
+		if (!ASSERT_OK(err, "Add random value to map_bloom"))
+			goto error;
+
+		rand_vals[i] = val;
+	}
+
+	*out_skel = skel;
+	*out_rand_vals = rand_vals;
+	*out_nr_rand_vals = map_size;
+
+	return 0;
+
+error:
+	bloom_filter_map__destroy(skel);
+	if (rand_vals)
+		free(rand_vals);
+	return err;
+}
+
+void test_bloom_filter_map(void)
+{
+	__u32 *rand_vals, nr_rand_vals;
+	struct bloom_filter_map *skel;
+	int err;
+
+	test_fail_cases();
+
+	err = setup_progs(&skel, &rand_vals, &nr_rand_vals);
+	if (err)
+		return;
+
+	test_inner_map(skel, rand_vals, nr_rand_vals);
+	free(rand_vals);
+
+	check_bloom(skel);
+
+	bloom_filter_map__destroy(skel);
+}

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

+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021 Facebook */
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+char _license[] SEC("license") = "GPL";
+
+struct bpf_map;
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__type(key, __u32);
+	__type(value, __u32);
+	__uint(max_entries, 1000);
+} map_random_data SEC(".maps");
+
+struct map_bloom_type {
+	__uint(type, BPF_MAP_TYPE_BLOOM_FILTER);
+	__type(value, __u32);
+	__uint(max_entries, 10000);
+	__uint(map_extra, 5);
+} map_bloom SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
+	__type(key, int);
+	__type(value, int);
+	__uint(max_entries, 1);
+	__array(values, struct map_bloom_type);
+} outer_map SEC(".maps");
+
+struct callback_ctx {
+	struct bpf_map *map;
+};
+
+int error = 0;
+
+static __u64
+check_elem(struct bpf_map *map, __u32 *key, __u32 *val,
+	   struct callback_ctx *data)
+{
+	int err;
+
+	err = bpf_map_peek_elem(data->map, val);
+	if (err) {
+		error |= 1;
+		return 1; /* stop the iteration */
+	}
+
+	return 0;
+}
+
+SEC("fentry/__x64_sys_getpgid")
+int inner_map(void *ctx)
+{
+	struct bpf_map *inner_map;
+	struct callback_ctx data;
+	int key = 0;
+
+	inner_map = bpf_map_lookup_elem(&outer_map, &key);
+	if (!inner_map) {
+		error |= 2;
+		return 0;
+	}
+
+	data.map = inner_map;
+	bpf_for_each_map_elem(&map_random_data, check_elem, &data, 0);
+
+	return 0;
+}
+
+SEC("fentry/__x64_sys_getpgid")
+int check_bloom(void *ctx)
+{
+	struct callback_ctx data;
+
+	data.map = (struct bpf_map *)&map_bloom;
+	bpf_for_each_map_elem(&map_random_data, check_elem, &data, 0);
+
+	return 0;
+}