1 /*
2  * Copyright (C) 2021 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #pragma once
18 
19 /* Mock BPF helpers to be used for testing of BPF programs loaded by Android */
20 
21 #include <linux/bpf.h>
22 #include <stdbool.h>
23 #include <stdint.h>
24 
25 #include <cutils/android_filesystem_config.h>
26 
27 typedef void* mock_bpf_map_t;
28 
29 /* type safe macro to declare a map and related accessor functions */
30 #define DEFINE_BPF_MAP_UGM(the_map, TYPE, TypeOfKey, TypeOfValue, num_entries, usr, grp, md)     \
31     mock_bpf_map_t mock_bpf_map_##the_map;                                                       \
32                                                                                                  \
33     mock_bpf_map_t get_mock_bpf_map_##the_map() {                                                \
34         if (mock_bpf_map_##the_map == 0) {                                                       \
35             mock_bpf_map_##the_map = mock_bpf_map_create(sizeof(TypeOfKey), sizeof(TypeOfValue), \
36                                                          BPF_MAP_TYPE_##TYPE);                   \
37         }                                                                                        \
38         return mock_bpf_map_##the_map;                                                           \
39     }                                                                                            \
40     __unused TypeOfValue* bpf_##the_map##_lookup_elem(const TypeOfKey* k) {                      \
41         return (TypeOfValue*)mock_bpf_lookup_elem(get_mock_bpf_map_##the_map(), (void*)k);       \
42     };                                                                                           \
43                                                                                                  \
44     __unused int bpf_##the_map##_update_elem(const TypeOfKey* k, const TypeOfValue* v,           \
45                                              uint64_t flags) {                                   \
46         return mock_bpf_update_elem(get_mock_bpf_map_##the_map(), (void*)k, (void*)v, flags);    \
47     };                                                                                           \
48                                                                                                  \
49     __unused int bpf_##the_map##_delete_elem(const TypeOfKey* k) {                               \
50         return mock_bpf_delete_elem(get_mock_bpf_map_##the_map(), (void*)k);                     \
51     };
52 
53 #define DEFINE_BPF_MAP(the_map, TYPE, TypeOfKey, TypeOfValue, num_entries) \
54     DEFINE_BPF_MAP_UGM(the_map, TYPE, TypeOfKey, TypeOfValue, num_entries, AID_ROOT, AID_ROOT, 0600)
55 
56 #define DEFINE_BPF_MAP_GWO(the_map, TYPE, TypeOfKey, TypeOfValue, num_entries, gid) \
57     DEFINE_BPF_MAP_UGM(the_map, TYPE, TypeOfKey, TypeOfValue, num_entries, AID_ROOT, gid, 0620)
58 
59 #define DEFINE_BPF_MAP_GRO(the_map, TYPE, TypeOfKey, TypeOfValue, num_entries, gid) \
60     DEFINE_BPF_MAP_UGM(the_map, TYPE, TypeOfKey, TypeOfValue, num_entries, AID_ROOT, gid, 0640)
61 
62 #define DEFINE_BPF_MAP_GRW(the_map, TYPE, TypeOfKey, TypeOfValue, num_entries, gid) \
63     DEFINE_BPF_MAP_UGM(the_map, TYPE, TypeOfKey, TypeOfValue, num_entries, AID_ROOT, gid, 0660)
64 
65 #define DEFINE_BPF_PROG(section, owner, group, name) int name
66 
67 #ifdef __cplusplus
68 extern "C" {
69 #endif
70 
71 mock_bpf_map_t mock_bpf_map_create(uint32_t key_size, uint32_t value_size, uint32_t type);
72 void* mock_bpf_lookup_elem(mock_bpf_map_t map, void* key);
73 int mock_bpf_update_elem(mock_bpf_map_t map, void* key, void* value, uint64_t flags);
74 int mock_bpf_delete_elem(mock_bpf_map_t map, void* key);
75 
76 uint64_t bpf_ktime_get_ns();
77 uint64_t bpf_get_smp_processor_id();
78 uint64_t bpf_get_current_uid_gid();
79 uint64_t bpf_get_current_pid_tgid();
80 
81 void mock_bpf_set_ktime_ns(uint64_t time_ns);
82 void mock_bpf_set_smp_processor_id(uint32_t cpu);
83 void mock_bpf_set_current_uid_gid(uint32_t uid);
84 void mock_bpf_set_current_pid_tgid(uint64_t pid_tgid);
85 
86 #ifdef __cplusplus
87 }  // extern "C"
88 #endif
89 
90 /* place things in different elf sections */
91 #define SECTION(NAME) __attribute__((section(NAME), used))
92 
93 /* Example use: LICENSE("GPL"); or LICENSE("Apache 2.0"); */
94 #define LICENSE(NAME) char _license[] SECTION("license") = (NAME)
95