content: /*
   * Copyright (C) 2015 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.
   */
  
  package android.net.util;
  
  import static android.system.OsConstants.SOL_SOCKET;
  import static android.system.OsConstants.SO_BINDTODEVICE;
  
  import android.annotation.NonNull;
  import android.annotation.Nullable;
  import android.annotation.SystemApi;
  import android.annotation.TestApi;
  import android.net.NetworkUtils;
  import android.system.ErrnoException;
  import android.system.NetlinkSocketAddress;
  import android.system.Os;
  import android.system.PacketSocketAddress;
  
  import libcore.io.IoBridge;
  
  import java.io.FileDescriptor;
  import java.io.IOException;
  import java.net.SocketAddress;
  
  /**
   * Collection of utilities to interact with raw sockets.
   * @hide
   */
  @SystemApi
  @TestApi
  public final class SocketUtils {
      /**
       * Create a raw datagram socket that is bound to an interface.
       *
       * <p>Data sent through the socket will go directly to the underlying network, ignoring VPNs.
       */
      public static void bindSocketToInterface(@NonNull FileDescriptor socket, @NonNull String iface)
              throws ErrnoException {
          // SO_BINDTODEVICE actually takes a string. This works because the first member
          // of struct ifreq is a NULL-terminated interface name.
          // TODO: add a setsockoptString()
          Os.setsockoptIfreq(socket, SOL_SOCKET, SO_BINDTODEVICE, iface);
          NetworkUtils.protectFromVpn(socket);
      }
  
      /**
       * Make a socket address to communicate with netlink.
       */
      @NonNull
      public static SocketAddress makeNetlinkSocketAddress(int portId, int groupsMask) {
          return new NetlinkSocketAddress(portId, groupsMask);
      }
  
      /**
       * Make socket address that packet sockets can bind to.
       */
      @NonNull
      public static SocketAddress makePacketSocketAddress(int protocol, int ifIndex) {
          return new PacketSocketAddress((short) protocol, ifIndex);
      }
  
      /**
       * Make a socket address that packet socket can send packets to.
       */
      @NonNull
      public static SocketAddress makePacketSocketAddress(int ifIndex, @NonNull byte[] hwAddr) {
          return new PacketSocketAddress(ifIndex, hwAddr);
      }
  
      /**
       * @see IoBridge#closeAndSignalBlockedThreads(FileDescriptor)
       */
      public static void closeSocket(@Nullable FileDescriptor fd) throws IOException {
          IoBridge.closeAndSignalBlockedThreads(fd);
      }
  
      private SocketUtils() {}
  }
  