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 30 static int timer_cb(void *map, u64 *key, struct timer_value *value) 31 { 32 return 0; 33 } 34 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 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") 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") 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