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