1/* SPDX-License-Identifier: GPL-2.0 */
2/* Copyright (c) 2020 Facebook */
3#include <linux/bpf.h>
4#include <bpf/bpf_helpers.h>
5
6struct inner_map {
7 __uint(type, BPF_MAP_TYPE_ARRAY);
8 __uint(max_entries, 1);
9 __type(key, int);
10 __type(value, int);
11} inner_map1 SEC(".maps"),
12 inner_map2 SEC(".maps");
13
14struct inner_map_sz2 {
15 __uint(type, BPF_MAP_TYPE_ARRAY);
16 __uint(max_entries, 2);
17 __type(key, int);
18 __type(value, int);
19} inner_map_sz2 SEC(".maps");
20
21struct outer_arr {
22 __uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
23 __uint(max_entries, 3);
24 __type(key, int);
25 __type(value, int);
26 /* it's possible to use anonymous struct as inner map definition here */
27 __array(values, struct {
28 __uint(type, BPF_MAP_TYPE_ARRAY);
29 /* changing max_entries to 2 will fail during load
30 * due to incompatibility with inner_map definition */
31 __uint(max_entries, 1);
32 __type(key, int);
33 __type(value, int);
34 });
35} outer_arr SEC(".maps") = {
36 /* (void *) cast is necessary because we didn't use `struct inner_map`
37 * in __inner(values, ...)
38 * Actually, a conscious effort is required to screw up initialization
39 * of inner map slots, which is a great thing!
40 */
41 .values = { (void *)&inner_map1, 0, (void *)&inner_map2 },
42};
43
44struct inner_map_sz3 {
45 __uint(type, BPF_MAP_TYPE_ARRAY);
46 __uint(map_flags, BPF_F_INNER_MAP);
47 __uint(max_entries, 3);
48 __type(key, int);
49 __type(value, int);
50} inner_map3 SEC(".maps"),
51 inner_map4 SEC(".maps");
52
53struct inner_map_sz4 {
54 __uint(type, BPF_MAP_TYPE_ARRAY);
55 __uint(map_flags, BPF_F_INNER_MAP);
56 __uint(max_entries, 5);
57 __type(key, int);
58 __type(value, int);
59} inner_map5 SEC(".maps");
60
61struct outer_arr_dyn {
62 __uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
63 __uint(max_entries, 3);
64 __type(key, int);
65 __type(value, int);
66 __array(values, struct {
67 __uint(type, BPF_MAP_TYPE_ARRAY);
68 __uint(map_flags, BPF_F_INNER_MAP);
69 __uint(max_entries, 1);
70 __type(key, int);
71 __type(value, int);
72 });
73} outer_arr_dyn SEC(".maps") = {
74 .values = {
75 [0] = (void *)&inner_map3,
76 [1] = (void *)&inner_map4,
77 [2] = (void *)&inner_map5,
78 },
79};
80
81struct outer_hash {
82 __uint(type, BPF_MAP_TYPE_HASH_OF_MAPS);
83 __uint(max_entries, 5);
84 __type(key, int);
85 /* Here everything works flawlessly due to reuse of struct inner_map
86 * and compiler will complain at the attempt to use non-inner_map
87 * references below. This is great experience.
88 */
89 __array(values, struct inner_map);
90} outer_hash SEC(".maps") = {
91 .values = {
92 [0] = &inner_map2,
93 [4] = &inner_map1,
94 },
95};
96
97struct sockarr_sz1 {
98 __uint(type, BPF_MAP_TYPE_REUSEPORT_SOCKARRAY);
99 __uint(max_entries, 1);
100 __type(key, int);
101 __type(value, int);
102} sockarr_sz1 SEC(".maps");
103
104struct sockarr_sz2 {
105 __uint(type, BPF_MAP_TYPE_REUSEPORT_SOCKARRAY);
106 __uint(max_entries, 2);
107 __type(key, int);
108 __type(value, int);
109} sockarr_sz2 SEC(".maps");
110
111struct outer_sockarr_sz1 {
112 __uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
113 __uint(max_entries, 1);
114 __type(key, int);
115 __type(value, int);
116 __array(values, struct sockarr_sz1);
117} outer_sockarr SEC(".maps") = {
118 .values = { (void *)&sockarr_sz1 },
119};
120
121int input = 0;
122
123SEC("raw_tp/sys_enter")
124int handle__sys_enter(void *ctx)
125{
126 struct inner_map *inner_map;
127 int key = 0, val;
128
129 inner_map = bpf_map_lookup_elem(&outer_arr, &key);
130 if (!inner_map)
131 return 1;
132 val = input;
133 bpf_map_update_elem(inner_map, &key, &val, 0);
134
135 inner_map = bpf_map_lookup_elem(&outer_hash, &key);
136 if (!inner_map)
137 return 1;
138 val = input + 1;
139 bpf_map_update_elem(inner_map, &key, &val, 0);
140
141 inner_map = bpf_map_lookup_elem(&outer_arr_dyn, &key);
142 if (!inner_map)
143 return 1;
144 val = input + 2;
145 bpf_map_update_elem(inner_map, &key, &val, 0);
146
147 return 0;
148}
149
150char _license[] SEC("license") = "GPL";
151

source code of linux/tools/testing/selftests/bpf/progs/test_btf_map_in_map.c