1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2020 Facebook */
3 #include "bpf_iter.h"
4 #include <bpf/bpf_helpers.h>
5
6 char _license[] SEC("license") = "GPL";
7
8 struct key_t {
9 int a;
10 int b;
11 int c;
12 };
13
14 struct {
15 __uint(type, BPF_MAP_TYPE_HASH);
16 __uint(max_entries, 3);
17 __type(key, struct key_t);
18 __type(value, __u64);
19 } hashmap1 SEC(".maps");
20
21 struct {
22 __uint(type, BPF_MAP_TYPE_HASH);
23 __uint(max_entries, 3);
24 __type(key, __u64);
25 __type(value, __u64);
26 } hashmap2 SEC(".maps");
27
28 struct {
29 __uint(type, BPF_MAP_TYPE_HASH);
30 __uint(max_entries, 3);
31 __type(key, struct key_t);
32 __type(value, __u32);
33 } hashmap3 SEC(".maps");
34
35 /* will set before prog run */
36 bool in_test_mode = 0;
37
38 /* will collect results during prog run */
39 __u32 key_sum_a = 0, key_sum_b = 0, key_sum_c = 0;
40 __u64 val_sum = 0;
41
42 SEC("iter/bpf_map_elem")
dump_bpf_hash_map(struct bpf_iter__bpf_map_elem * ctx)43 int dump_bpf_hash_map(struct bpf_iter__bpf_map_elem *ctx)
44 {
45 struct seq_file *seq = ctx->meta->seq;
46 __u32 seq_num = ctx->meta->seq_num;
47 struct bpf_map *map = ctx->map;
48 struct key_t *key = ctx->key;
49 struct key_t tmp_key;
50 __u64 *val = ctx->value;
51 __u64 tmp_val = 0;
52 int ret;
53
54 if (in_test_mode) {
55 /* test mode is used by selftests to
56 * test functionality of bpf_hash_map iter.
57 *
58 * the above hashmap1 will have correct size
59 * and will be accepted, hashmap2 and hashmap3
60 * should be rejected due to smaller key/value
61 * size.
62 */
63 if (key == (void *)0 || val == (void *)0)
64 return 0;
65
66 /* update the value and then delete the <key, value> pair.
67 * it should not impact the existing 'val' which is still
68 * accessible under rcu.
69 */
70 __builtin_memcpy(&tmp_key, key, sizeof(struct key_t));
71 ret = bpf_map_update_elem(&hashmap1, &tmp_key, &tmp_val, 0);
72 if (ret)
73 return 0;
74 ret = bpf_map_delete_elem(&hashmap1, &tmp_key);
75 if (ret)
76 return 0;
77
78 key_sum_a += key->a;
79 key_sum_b += key->b;
80 key_sum_c += key->c;
81 val_sum += *val;
82 return 0;
83 }
84
85 /* non-test mode, the map is prepared with the
86 * below bpftool command sequence:
87 * bpftool map create /sys/fs/bpf/m1 type hash \
88 * key 12 value 8 entries 3 name map1
89 * bpftool map update id 77 key 0 0 0 1 0 0 0 0 0 0 0 1 \
90 * value 0 0 0 1 0 0 0 1
91 * bpftool map update id 77 key 0 0 0 1 0 0 0 0 0 0 0 2 \
92 * value 0 0 0 1 0 0 0 2
93 * The bpftool iter command line:
94 * bpftool iter pin ./bpf_iter_bpf_hash_map.o /sys/fs/bpf/p1 \
95 * map id 77
96 * The below output will be:
97 * map dump starts
98 * 77: (1000000 0 2000000) (200000001000000)
99 * 77: (1000000 0 1000000) (100000001000000)
100 * map dump ends
101 */
102 if (seq_num == 0)
103 BPF_SEQ_PRINTF(seq, "map dump starts\n");
104
105 if (key == (void *)0 || val == (void *)0) {
106 BPF_SEQ_PRINTF(seq, "map dump ends\n");
107 return 0;
108 }
109
110 BPF_SEQ_PRINTF(seq, "%d: (%x %d %x) (%llx)\n", map->id,
111 key->a, key->b, key->c, *val);
112
113 return 0;
114 }
115
116 SEC("iter.s/bpf_map_elem")
sleepable_dummy_dump(struct bpf_iter__bpf_map_elem * ctx)117 int sleepable_dummy_dump(struct bpf_iter__bpf_map_elem *ctx)
118 {
119 if (ctx->meta->seq_num == 0)
120 BPF_SEQ_PRINTF(ctx->meta->seq, "map dump starts\n");
121
122 return 0;
123 }
124