1 // SPDX-License-Identifier: GPL-2.0
2
3 #include <vmlinux.h>
4 #include <errno.h>
5 #include <bpf/bpf_helpers.h>
6
7 #define CLOCK_MONOTONIC 1
8 #define TIMER_NSEC (60ULL * 1000 * 1000 * 1000)
9
10 struct timer_value {
11 struct bpf_timer timer;
12 u64 data;
13 };
14
15 struct {
16 __uint(type, BPF_MAP_TYPE_RHASH);
17 __uint(map_flags, BPF_F_NO_PREALLOC);
18 __uint(max_entries, 1);
19 __type(key, u64);
20 __type(value, struct timer_value);
21 } timer_map SEC(".maps");
22
23 u64 armed;
24 u64 cancelled;
25 long timer_init_err;
26 long timer_set_callback_err;
27 long timer_start_err;
28 long timer_cancel_err;
29
timer_cb(void * map,u64 * key,struct timer_value * value)30 static int timer_cb(void *map, u64 *key, struct timer_value *value)
31 {
32 return 0;
33 }
34
arm_timer_cb(struct bpf_map * map,u64 * key,struct timer_value * value,void * ctx)35 static long arm_timer_cb(struct bpf_map *map, u64 *key,
36 struct timer_value *value, void *ctx)
37 {
38 u64 key_copy = *key;
39 long err;
40
41 err = bpf_map_delete_elem(map, &key_copy);
42 if (err)
43 return 1;
44
45 err = bpf_timer_init(&value->timer, map, CLOCK_MONOTONIC);
46 if (err) {
47 timer_init_err = err;
48 return 1;
49 }
50
51 err = bpf_timer_set_callback(&value->timer, timer_cb);
52 if (err) {
53 timer_set_callback_err = err;
54 return 1;
55 }
56
57 err = bpf_timer_start(&value->timer, TIMER_NSEC, BPF_F_TIMER_CPU_PIN);
58 if (err) {
59 timer_start_err = err;
60 return 1;
61 }
62
63 __sync_fetch_and_add(&armed, 1);
64 return 1;
65 }
66
cancel_timer_cb(struct bpf_map * map,u64 * key,struct timer_value * value,void * ctx)67 static long cancel_timer_cb(struct bpf_map *map, u64 *key,
68 struct timer_value *value, void *ctx)
69 {
70 long err;
71
72 err = bpf_timer_cancel(&value->timer);
73 if (err == -EINVAL)
74 return 1;
75 if (err < 0) {
76 timer_cancel_err = err;
77 return 1;
78 }
79
80 __sync_fetch_and_add(&cancelled, 1);
81 return 1;
82 }
83
84 SEC("syscall")
arm_deleted_timer(void * ctx)85 int arm_deleted_timer(void *ctx)
86 {
87 bpf_for_each_map_elem(&timer_map, arm_timer_cb, NULL, 0);
88 return 0;
89 }
90
91 SEC("syscall")
cancel_recycled_timer(void * ctx)92 int cancel_recycled_timer(void *ctx)
93 {
94 bpf_for_each_map_elem(&timer_map, cancel_timer_cb, NULL, 0);
95 return 0;
96 }
97
98 char _license[] SEC("license") = "GPL";
99