Check for first api level before turn on eBPF

The api check will ensure the device is running 4.9 or above kernel and
is shipped originally with P release. Also add some test to make sure
eligible devices always have eBPF turned on.

Test: ./netd_integration_test
Bug: 79408692
Change-Id: Ief56a95aab892c92276a5b4ac74b03f9f32f5b54
diff --git a/tests/bpf_base_test.cpp b/tests/bpf_base_test.cpp
new file mode 100644
index 0000000..41945e2
--- /dev/null
+++ b/tests/bpf_base_test.cpp
@@ -0,0 +1,140 @@
+/*
+ * Copyright (C) 2018 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.
+ */
+
+#include <string>
+
+#include <fcntl.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <linux/inet_diag.h>
+#include <linux/sock_diag.h>
+#include <net/if.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <gtest/gtest.h>
+
+#include <cutils/qtaguid.h>
+
+#include <android-base/stringprintf.h>
+#include <android-base/strings.h>
+
+#include "bpf/BpfUtils.h"
+
+using namespace android::bpf;
+
+using android::base::unique_fd;
+using android::netdutils::status::ok;
+
+namespace android {
+namespace bpf {
+
+// Use the upper limit of uid to avoid conflict with real app uids. We can't use UID_MAX because
+// it's -1, which is INVALID_UID.
+constexpr uid_t TEST_UID = UID_MAX - 1;
+constexpr uint32_t TEST_TAG = 42;
+constexpr int TEST_COUNTERSET = 1;
+constexpr int DEFAULT_COUNTERSET = 0;
+
+class BpfBasicTest : public testing::Test {
+  protected:
+    BpfBasicTest() {}
+};
+
+TEST_F(BpfBasicTest, TestCgroupMounted) {
+    SKIP_IF_BPF_NOT_SUPPORTED;
+
+    ASSERT_EQ(0, access(CGROUP_ROOT_PATH, R_OK));
+    ASSERT_EQ(0, access("/dev/cg2_bpf/cgroup.controllers", R_OK));
+}
+
+TEST_F(BpfBasicTest, TestTrafficControllerSetUp) {
+    SKIP_IF_BPF_NOT_SUPPORTED;
+
+    ASSERT_EQ(0, access(BPF_EGRESS_PROG_PATH, R_OK));
+    ASSERT_EQ(0, access(BPF_INGRESS_PROG_PATH, R_OK));
+    ASSERT_EQ(0, access(XT_BPF_INGRESS_PROG_PATH, R_OK));
+    ASSERT_EQ(0, access(XT_BPF_EGRESS_PROG_PATH, R_OK));
+    ASSERT_EQ(0, access(COOKIE_TAG_MAP_PATH, R_OK));
+    ASSERT_EQ(0, access(UID_COUNTERSET_MAP_PATH, R_OK));
+    ASSERT_EQ(0, access(UID_STATS_MAP_PATH, R_OK));
+    ASSERT_EQ(0, access(TAG_STATS_MAP_PATH, R_OK));
+    ASSERT_EQ(0, access(IFACE_INDEX_NAME_MAP_PATH, R_OK));
+    ASSERT_EQ(0, access(IFACE_STATS_MAP_PATH, R_OK));
+    ASSERT_EQ(0, access(DOZABLE_UID_MAP_PATH, R_OK));
+    ASSERT_EQ(0, access(STANDBY_UID_MAP_PATH, R_OK));
+    ASSERT_EQ(0, access(POWERSAVE_UID_MAP_PATH, R_OK));
+}
+
+TEST_F(BpfBasicTest, TestTagSocket) {
+    SKIP_IF_BPF_NOT_SUPPORTED;
+
+    unique_fd cookieTagMap = unique_fd(mapRetrieve(COOKIE_TAG_MAP_PATH, 0));
+    ASSERT_LE(0, cookieTagMap);
+    int sock = socket(AF_INET6, SOCK_STREAM, 0);
+    ASSERT_LE(0, sock);
+    uint64_t cookie = getSocketCookie(sock);
+    ASSERT_NE(NONEXISTENT_COOKIE, cookie);
+    ASSERT_EQ(0, qtaguid_tagSocket(sock, TEST_TAG, TEST_UID));
+    struct UidTag tagResult;
+    ASSERT_EQ(0, findMapEntry(cookieTagMap, &cookie, &tagResult));
+    ASSERT_EQ(TEST_UID, tagResult.uid);
+    ASSERT_EQ(TEST_TAG, tagResult.tag);
+    ASSERT_EQ(0, qtaguid_untagSocket(sock));
+    ASSERT_EQ(-1, findMapEntry(cookieTagMap, &cookie, &tagResult));
+    ASSERT_EQ(ENOENT, errno);
+}
+
+TEST_F(BpfBasicTest, TestChangeCounterSet) {
+    SKIP_IF_BPF_NOT_SUPPORTED;
+
+    unique_fd uidCounterSetMap = unique_fd(mapRetrieve(UID_COUNTERSET_MAP_PATH, 0));
+    ASSERT_LE(0, uidCounterSetMap);
+    ASSERT_EQ(0, qtaguid_setCounterSet(TEST_COUNTERSET, TEST_UID));
+    uid_t uid = TEST_UID;
+    int counterSetResult;
+    ASSERT_EQ(0, findMapEntry(uidCounterSetMap, &uid, &counterSetResult));
+    ASSERT_EQ(TEST_COUNTERSET, counterSetResult);
+    ASSERT_EQ(0, qtaguid_setCounterSet(DEFAULT_COUNTERSET, TEST_UID));
+    ASSERT_EQ(-1, findMapEntry(uidCounterSetMap, &uid, &counterSetResult));
+    ASSERT_EQ(ENOENT, errno);
+}
+
+TEST_F(BpfBasicTest, TestDeleteTagData) {
+    SKIP_IF_BPF_NOT_SUPPORTED;
+
+    unique_fd uidStatsMap = unique_fd(mapRetrieve(UID_STATS_MAP_PATH, 0));
+    ASSERT_LE(0, uidStatsMap);
+    unique_fd tagStatsMap = unique_fd(mapRetrieve(TAG_STATS_MAP_PATH, 0));
+    ASSERT_LE(0, tagStatsMap);
+
+    StatsKey key = {.uid = TEST_UID, .tag = TEST_TAG, .counterSet = TEST_COUNTERSET,
+                    .ifaceIndex = 1};
+    StatsValue statsMapValue = {.rxPackets = 1, .rxBytes = 100};
+    EXPECT_EQ(0, writeToMapEntry(tagStatsMap, &key, &statsMapValue, BPF_ANY));
+    key.tag = 0;
+    EXPECT_EQ(0, writeToMapEntry(uidStatsMap, &key, &statsMapValue, BPF_ANY));
+    ASSERT_EQ(0, qtaguid_deleteTagData(0, TEST_UID));
+    ASSERT_EQ(-1, findMapEntry(uidStatsMap, &key, &statsMapValue));
+    ASSERT_EQ(ENOENT, errno);
+    key.tag = TEST_TAG;
+    ASSERT_EQ(-1, findMapEntry(tagStatsMap, &key, &statsMapValue));
+    ASSERT_EQ(ENOENT, errno);
+}
+
+}
+}