1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2021 Facebook */
3 #include "vmlinux.h"
4 #include <bpf/bpf_helpers.h>
5
6 char _license[] SEC("license") = "GPL";
7
8 struct {
9 __uint(type, BPF_MAP_TYPE_HASH);
10 __uint(max_entries, 3);
11 __type(key, __u32);
12 __type(value, __u64);
13 } hashmap SEC(".maps");
14
15 struct {
16 __uint(type, BPF_MAP_TYPE_PERCPU_HASH);
17 __uint(max_entries, 1);
18 __type(key, __u32);
19 __type(value, __u64);
20 } percpu_map SEC(".maps");
21
22 struct callback_ctx {
23 struct __sk_buff *ctx;
24 int input;
25 int output;
26 };
27
28 static __u64
check_hash_elem(struct bpf_map * map,__u32 * key,__u64 * val,struct callback_ctx * data)29 check_hash_elem(struct bpf_map *map, __u32 *key, __u64 *val,
30 struct callback_ctx *data)
31 {
32 struct __sk_buff *skb = data->ctx;
33 __u32 k;
34 __u64 v;
35
36 if (skb) {
37 k = *key;
38 v = *val;
39 if (skb->len == 10000 && k == 10 && v == 10)
40 data->output = 3; /* impossible path */
41 else
42 data->output = 4;
43 } else {
44 data->output = data->input;
45 bpf_map_delete_elem(map, key);
46 }
47
48 return 0;
49 }
50
51 __u32 cpu = 0;
52 __u32 percpu_called = 0;
53 __u32 percpu_key = 0;
54 __u64 percpu_val = 0;
55 int percpu_output = 0;
56
57 static __u64
check_percpu_elem(struct bpf_map * map,__u32 * key,__u64 * val,struct callback_ctx * unused)58 check_percpu_elem(struct bpf_map *map, __u32 *key, __u64 *val,
59 struct callback_ctx *unused)
60 {
61 struct callback_ctx data;
62
63 percpu_called++;
64 cpu = bpf_get_smp_processor_id();
65 percpu_key = *key;
66 percpu_val = *val;
67
68 data.ctx = 0;
69 data.input = 100;
70 data.output = 0;
71 bpf_for_each_map_elem(&hashmap, check_hash_elem, &data, 0);
72 percpu_output = data.output;
73
74 return 0;
75 }
76
77 int hashmap_output = 0;
78 int hashmap_elems = 0;
79 int percpu_map_elems = 0;
80
81 SEC("tc")
test_pkt_access(struct __sk_buff * skb)82 int test_pkt_access(struct __sk_buff *skb)
83 {
84 struct callback_ctx data;
85
86 data.ctx = skb;
87 data.input = 10;
88 data.output = 0;
89 hashmap_elems = bpf_for_each_map_elem(&hashmap, check_hash_elem, &data, 0);
90 hashmap_output = data.output;
91
92 percpu_map_elems = bpf_for_each_map_elem(&percpu_map, check_percpu_elem,
93 (void *)0, 0);
94 return 0;
95 }
96