1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2021 Facebook */
3 #include <linux/bpf.h>
4 #include <time.h>
5 #include <errno.h>
6 #include <bpf/bpf_helpers.h>
7 #include <bpf/bpf_tracing.h>
8
9 char _license[] SEC("license") = "GPL";
10 struct hmap_elem {
11 int pad; /* unused */
12 struct bpf_timer timer;
13 };
14
15 struct inner_map {
16 __uint(type, BPF_MAP_TYPE_HASH);
17 __uint(max_entries, 1024);
18 __type(key, int);
19 __type(value, struct hmap_elem);
20 } inner_htab SEC(".maps");
21
22 #define ARRAY_KEY 1
23 #define ARRAY_KEY2 2
24 #define HASH_KEY 1234
25
26 struct outer_arr {
27 __uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
28 __uint(max_entries, 2);
29 __uint(key_size, sizeof(int));
30 __uint(value_size, sizeof(int));
31 __array(values, struct inner_map);
32 } outer_arr SEC(".maps") = {
33 .values = { [ARRAY_KEY] = &inner_htab },
34 };
35
36 __u64 err;
37 __u64 ok;
38 __u64 cnt;
39
40 /* callback for inner hash map */
41 static int timer_cb(void *map, int *key, struct hmap_elem *val)
42 {
43 return 0;
44 }
45
46 SEC("fentry/bpf_fentry_test1")
47 int BPF_PROG(test1, int a)
48 {
49 struct hmap_elem init = {};
50 struct bpf_map *inner_map, *inner_map2;
51 struct hmap_elem *val;
52 int array_key = ARRAY_KEY;
53 int array_key2 = ARRAY_KEY2;
54 int hash_key = HASH_KEY;
55
56 inner_map = bpf_map_lookup_elem(&outer_arr, &array_key);
57 if (!inner_map)
58 return 0;
59
60 inner_map2 = bpf_map_lookup_elem(&outer_arr, &array_key2);
61 if (!inner_map2)
62 return 0;
63 bpf_map_update_elem(inner_map, &hash_key, &init, 0);
64 val = bpf_map_lookup_elem(inner_map, &hash_key);
65 if (!val)
66 return 0;
67
68 bpf_timer_init(&val->timer, inner_map2, CLOCK_MONOTONIC);
69 if (bpf_timer_set_callback(&val->timer, timer_cb))
70 err |= 4;
71 if (bpf_timer_start(&val->timer, 0, 0))
72 err |= 8;
73 return 0;
74 }
75
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