1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2021 Facebook */
3
4#include <linux/bpf.h>
5#include <bpf/bpf_helpers.h>
6#include "bpf_misc.h"
7
8char _license[] SEC("license") = "GPL";
9
10struct bpf_map;
11
12struct {
13	__uint(type, BPF_MAP_TYPE_ARRAY);
14	__type(key, __u32);
15	__type(value, __u32);
16	__uint(max_entries, 1000);
17} map_random_data SEC(".maps");
18
19struct map_bloom_type {
20	__uint(type, BPF_MAP_TYPE_BLOOM_FILTER);
21	__type(value, __u32);
22	__uint(max_entries, 10000);
23	__uint(map_extra, 5);
24} map_bloom SEC(".maps");
25
26struct {
27	__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
28	__type(key, int);
29	__type(value, int);
30	__uint(max_entries, 1);
31	__array(values, struct map_bloom_type);
32} outer_map SEC(".maps");
33
34struct callback_ctx {
35	struct bpf_map *map;
36};
37
38int error = 0;
39
40static __u64
41check_elem(struct bpf_map *map, __u32 *key, __u32 *val,
42	   struct callback_ctx *data)
43{
44	int err;
45
46	err = bpf_map_peek_elem(data->map, val);
47	if (err) {
48		error |= 1;
49		return 1; /* stop the iteration */
50	}
51
52	return 0;
53}
54
55SEC("fentry/" SYS_PREFIX "sys_getpgid")
56int inner_map(void *ctx)
57{
58	struct bpf_map *inner_map;
59	struct callback_ctx data;
60	int key = 0;
61
62	inner_map = bpf_map_lookup_elem(&outer_map, &key);
63	if (!inner_map) {
64		error |= 2;
65		return 0;
66	}
67
68	data.map = inner_map;
69	bpf_for_each_map_elem(&map_random_data, check_elem, &data, 0);
70
71	return 0;
72}
73
74SEC("fentry/" SYS_PREFIX "sys_getpgid")
75int check_bloom(void *ctx)
76{
77	struct callback_ctx data;
78
79	data.map = (struct bpf_map *)&map_bloom;
80	bpf_for_each_map_elem(&map_random_data, check_elem, &data, 0);
81
82	return 0;
83}
84