Add support for testing of eBPF programs

Bug: 171262763
Test: this is just a header file
Change-Id: Id25846f91d2da698717a9cc0d8d9091022dd7233
diff --git a/progs/include/test/mock_bpf_helpers.h b/progs/include/test/mock_bpf_helpers.h
new file mode 100644
index 0000000..ffe8951
--- /dev/null
+++ b/progs/include/test/mock_bpf_helpers.h
@@ -0,0 +1,92 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+/* Mock BPF helpers to be used for testing of BPF programs loaded by Android */
+
+#include <linux/bpf.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+typedef void* mock_bpf_map_t;
+
+/* type safe macro to declare a map and related accessor functions */
+#define DEFINE_BPF_MAP_UGM(the_map, TYPE, TypeOfKey, TypeOfValue, num_entries, usr, grp, md)     \
+    mock_bpf_map_t mock_bpf_map_##the_map;                                                       \
+                                                                                                 \
+    mock_bpf_map_t get_mock_bpf_map_##the_map() {                                                \
+        if (mock_bpf_map_##the_map == 0) {                                                       \
+            mock_bpf_map_##the_map = mock_bpf_map_create(sizeof(TypeOfKey), sizeof(TypeOfValue), \
+                                                         BPF_MAP_TYPE_##TYPE);                   \
+        }                                                                                        \
+        return mock_bpf_map_##the_map;                                                           \
+    }                                                                                            \
+    __unused TypeOfValue* bpf_##the_map##_lookup_elem(const TypeOfKey* k) {                      \
+        return (TypeOfValue*)mock_bpf_lookup_elem(get_mock_bpf_map_##the_map(), (void*)k);       \
+    };                                                                                           \
+                                                                                                 \
+    __unused int bpf_##the_map##_update_elem(const TypeOfKey* k, const TypeOfValue* v,           \
+                                             uint64_t flags) {                                   \
+        return mock_bpf_update_elem(get_mock_bpf_map_##the_map(), (void*)k, (void*)v, flags);    \
+    };                                                                                           \
+                                                                                                 \
+    __unused int bpf_##the_map##_delete_elem(const TypeOfKey* k) {                               \
+        return mock_bpf_delete_elem(get_mock_bpf_map_##the_map(), (void*)k);                     \
+    };
+
+#define DEFINE_BPF_MAP(the_map, TYPE, TypeOfKey, TypeOfValue, num_entries) \
+    DEFINE_BPF_MAP_UGM(the_map, TYPE, TypeOfKey, TypeOfValue, num_entries, AID_ROOT, AID_ROOT, 0600)
+
+#define DEFINE_BPF_MAP_GWO(the_map, TYPE, TypeOfKey, TypeOfValue, num_entries, gid) \
+    DEFINE_BPF_MAP_UGM(the_map, TYPE, TypeOfKey, TypeOfValue, num_entries, AID_ROOT, gid, 0620)
+
+#define DEFINE_BPF_MAP_GRO(the_map, TYPE, TypeOfKey, TypeOfValue, num_entries, gid) \
+    DEFINE_BPF_MAP_UGM(the_map, TYPE, TypeOfKey, TypeOfValue, num_entries, AID_ROOT, gid, 0640)
+
+#define DEFINE_BPF_MAP_GRW(the_map, TYPE, TypeOfKey, TypeOfValue, num_entries, gid) \
+    DEFINE_BPF_MAP_UGM(the_map, TYPE, TypeOfKey, TypeOfValue, num_entries, AID_ROOT, gid, 0660)
+
+#define DEFINE_BPF_PROG(section, owner, group, name) int name
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+mock_bpf_map_t mock_bpf_map_create(uint32_t key_size, uint32_t value_size, uint32_t type);
+void* mock_bpf_lookup_elem(mock_bpf_map_t map, void* key);
+int mock_bpf_update_elem(mock_bpf_map_t map, void* key, void* value, uint64_t flags);
+int mock_bpf_delete_elem(mock_bpf_map_t map, void* key);
+
+uint64_t bpf_ktime_get_ns();
+uint64_t bpf_get_smp_processor_id();
+uint64_t bpf_get_current_uid_gid();
+uint64_t bpf_get_current_pid_tgid();
+
+void mock_bpf_set_ktime_ns(uint64_t time_ns);
+void mock_bpf_set_smp_processor_id(uint32_t cpu);
+void mock_bpf_set_current_uid_gid(uint32_t uid);
+void mock_bpf_set_current_pid_tgid(uint64_t pid_tgid);
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
+/* place things in different elf sections */
+#define SEC(NAME) __attribute__((section(NAME), used))
+
+/* Example use: LICENSE("GPL"); or LICENSE("Apache 2.0"); */
+#define LICENSE(NAME) char _license[] SEC("license") = (NAME)