1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* Copyright (c) 2020 Facebook */
3 #include <linux/bpf.h>
4 #include <bpf/bpf_helpers.h>
5 
6 struct 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 
14 struct 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 
21 struct 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 
44 struct 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 
53 struct 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 
61 struct 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 
81 struct 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 
97 struct 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 
104 struct 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 
111 struct 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 
121 int input = 0;
122 
123 SEC("raw_tp/sys_enter")
handle__sys_enter(void * ctx)124 int 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 
150 char _license[] SEC("license") = "GPL";
151