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 HASH_KEY 1234
24
25 struct outer_arr {
26 __uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
27 __uint(max_entries, 2);
28 __uint(key_size, sizeof(int));
29 __uint(value_size, sizeof(int));
30 __array(values, struct inner_map);
31 } outer_arr SEC(".maps") = {
32 .values = { [ARRAY_KEY] = &inner_htab },
33 };
34
35 __u64 err;
36 __u64 ok;
37 __u64 cnt;
38
39 static int timer_cb1(void *map, int *key, struct hmap_elem *val);
40
41 static int timer_cb2(void *map, int *key, struct hmap_elem *val)
42 {
43 cnt++;
44 bpf_timer_set_callback(&val->timer, timer_cb1);
45 if (bpf_timer_start(&val->timer, 1000, 0))
46 err |= 1;
47 ok |= 1;
48 return 0;
49 }
50
51 /* callback for inner hash map */
52 static int timer_cb1(void *map, int *key, struct hmap_elem *val)
53 {
54 cnt++;
55 bpf_timer_set_callback(&val->timer, timer_cb2);
56 if (bpf_timer_start(&val->timer, 1000, 0))
57 err |= 2;
58 /* Do a lookup to make sure 'map' and 'key' pointers are correct */
59 bpf_map_lookup_elem(map, key);
60 ok |= 2;
61 return 0;
62 }
63
64 SEC("fentry/bpf_fentry_test1")
65 int BPF_PROG(test1, int a)
66 {
67 struct hmap_elem init = {};
68 struct bpf_map *inner_map;
69 struct hmap_elem *val;
70 int array_key = ARRAY_KEY;
71 int hash_key = HASH_KEY;
72
73 inner_map = bpf_map_lookup_elem(&outer_arr, &array_key);
74 if (!inner_map)
75 return 0;
76
77 bpf_map_update_elem(inner_map, &hash_key, &init, 0);
78 val = bpf_map_lookup_elem(inner_map, &hash_key);
79 if (!val)
80 return 0;
81
82 bpf_timer_init(&val->timer, inner_map, CLOCK_MONOTONIC);
83 if (bpf_timer_set_callback(&val->timer, timer_cb1))
84 err |= 4;
85 if (bpf_timer_start(&val->timer, 0, 0))
86 err |= 8;
87 return 0;
88 }
89
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