Move BpfUtils -- add JNI wrapper for libtcutils

This CL adds the copied JNI wrappers for tcutils.

Bug: 202086915
Bug: 157552970
Test: atest TetheringTests
Change-Id: Ib3f8b24a12a18f1ba64fd17304274c4dba37fc47

staticlibs/native/bpfmapjni/Android.bp

@@ -18,7 +18,10 @@ package {
 
 cc_library_static {
     name: "libnet_utils_device_common_bpfjni",
-    srcs: ["com_android_net_module_util_BpfMap.cpp"],
+    srcs: [
+        "com_android_net_module_util_BpfMap.cpp",
+        "com_android_net_module_util_TcUtils.cpp",
+    ],
     header_libs: [
         "bpf_syscall_wrappers",
         "jni_headers",
@@ -27,6 +30,9 @@ cc_library_static {
         "liblog",
         "libnativehelper_compat_libc++",
     ],
+    static_libs: [
+        "libtcutils",
+    ],
     cflags: [
         "-Wall",
         "-Werror",

staticlibs/native/bpfmapjni/com_android_net_module_util_TcUtils.cpp

@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2022 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 <jni.h>
+#include <nativehelper/JNIHelp.h>
+#include <nativehelper/scoped_utf_chars.h>
+#include <tcutils/tcutils.h>
+
+namespace android {
+
+static void throwIOException(JNIEnv *env, const char *msg, int error) {
+  jniThrowExceptionFmt(env, "java/io/IOException", "%s: %s", msg,
+                       strerror(error));
+}
+
+static jboolean com_android_net_module_util_TcUtils_isEthernet(JNIEnv *env,
+                                                               jobject clazz,
+                                                               jstring iface) {
+  ScopedUtfChars interface(env, iface);
+  bool result = false;
+  int error = isEthernet(interface.c_str(), result);
+  if (error) {
+    throwIOException(
+        env, "com_android_net_module_util_TcUtils_isEthernet error: ", error);
+  }
+  // result is not touched when error is returned; leave false.
+  return result;
+}
+
+// tc filter add dev .. in/egress prio 1 protocol ipv6/ip bpf object-pinned
+// /sys/fs/bpf/... direct-action
+static void com_android_net_module_util_TcUtils_tcFilterAddDevBpf(
+    JNIEnv *env, jobject clazz, jint ifIndex, jboolean ingress, jshort prio,
+    jshort proto, jstring bpfProgPath) {
+  ScopedUtfChars pathname(env, bpfProgPath);
+  int error = tcAddBpfFilter(ifIndex, ingress, prio, proto, pathname.c_str());
+  if (error) {
+    throwIOException(
+        env,
+        "com_android_net_module_util_TcUtils_tcFilterAddDevBpf error: ", error);
+  }
+}
+
+// tc filter del dev .. in/egress prio .. protocol ..
+static void com_android_net_module_util_TcUtils_tcFilterDelDev(
+    JNIEnv *env, jobject clazz, jint ifIndex, jboolean ingress, jshort prio,
+    jshort proto) {
+  int error = tcDeleteFilter(ifIndex, ingress, prio, proto);
+  if (error) {
+    throwIOException(
+        env,
+        "com_android_net_module_util_TcUtils_tcFilterDelDev error: ", error);
+  }
+}
+
+/*
+ * JNI registration.
+ */
+static const JNINativeMethod gMethods[] = {
+    /* name, signature, funcPtr */
+    {"isEthernet", "(Ljava/lang/String;)Z",
+     (void *)com_android_net_module_util_TcUtils_isEthernet},
+    {"tcFilterAddDevBpf", "(IZSSLjava/lang/String;)V",
+     (void *)com_android_net_module_util_TcUtils_tcFilterAddDevBpf},
+    {"tcFilterDelDev", "(IZSS)V",
+     (void *)com_android_net_module_util_TcUtils_tcFilterDelDev},
+};
+
+int register_com_android_net_module_util_TcUtils(JNIEnv *env,
+                                                 char const *class_name) {
+  return jniRegisterNativeMethods(env, class_name, gMethods, NELEM(gMethods));
+}
+
+}; // namespace android