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_tcp_helpers.h"
8
9char _license[] SEC("license") = "GPL";
10struct hmap_elem {
11	int pad; /* unused */
12	struct bpf_timer timer;
13};
14
15struct 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
25struct 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
39static int timer_cb1(void *map, int *key, struct hmap_elem *val);
40
41static 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 */
52static 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
64SEC("fentry/bpf_fentry_test1")
65int 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